1b (V2.0) Softswitch Control Equipment Technical Manual

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ZXSS10 SS1a/1b (V2.0) Softswitch Control Equipment

Technical Manual

ZTE CORPORATION

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ZXSS10 SS1a/1b (V2.0) Softswitch Control Equipment Technical Manual

Manual Version 20031020-R1.0 Product Version V2.0

Copyright ©ZTE Corporation

All rights reserved.

No part of this documentation may be excerpted, reproduced, translated, annotated or

duplicated, in any form or by any means without the prior written permission of ZTE

Corporation.

ZTE CORPORATION

ZTE Plaza, Keji Road South, Hi-Tech Industrial Park, Nanshan District, Shenzhen, P.R.China

Website: http://www.zte.com.cn

Postcode: 518057

Customer Support Center: (+86755) 26771900 800-9830-9830

Fax: (+86755) 26770801

Email: [email protected]

* * * *

S.N.: sjzl20040211

Preface

About This Manual

This manual intends to enable users to have a systematic and complete understanding

of the ZTE Softswitch core control equipment: ZXSS10 SS1a/1b. It lays a foundation

for using other supporting manuals such as the Operation Manual, Maintenance

Manual, Command Manual and Interface Manual and conducting operation &

maintenance on the equipment.

The Technical Manual is the core of the whole set of attached manuals of the

softswitch product. All other manuals provide further descriptions on the foundation of

the Technical Manual. This technical manual primarily describes the architecture,

operating principle, software structure, performance indices, external interfaces,

service functions and application examples of the softswitch product.

Major modules:

1. Basic knowledge: describes knowledge related to the softswitch system;

2. Architecture: describes the total structure and functions of the Softswitch

product and composition of the system;

3. Technical indices: describes technical indices of the softswitch product;

4. Interfaces and protocols: describes external interfaces and communication

protocols of the softswitch system;

5. Service functions: describes the service provisioning mode and capability of the

softswitch product.

6. Networking and configuration: describes the softswitch networking mode and

application.

This Technical Manual consists of the preface, contents, text and appendix.

How to Use This Manual

This manual includes six chapters. “Chapter 1 Basic Knowledge” describes the basic

conceptions of the data communication network and knowledge about the packet

switching technology; “Chapter 2 Architecture” simply describes the composition of

the softswitch system as well as the location of the softswitch control equipment in the

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system and its functions; “Chapter 3 Technical Indices” describes technical indices

related to ZXSS10 SS1a/1b; “Chapter 4 Interfaces and Protocols” describes interfaces

and communication protocols of ZXSS10 SS1a/1b; “Chapter 5 Service Functions”

describe service functions of ZXSS10 SS1a/1b; and “Chapter 6 Networking Mode and

Configuration” describes the networking application, configuration principles and

configuration examples of ZXSS10 SS1a/1b. In addition, the appendix describes

knowledge about the common technical index analysis methods, system protocol stacks,

small-capacity core equipment ZXSS10 SS1c and abbreviations.

This technical manual is intended for deployment engineering technical personnel as

well as daily maintenance personnel and maintenance management personnel of the

equipment room. You can either select relevant chapters according to the title of each

chapter such as “Architecture”, “Interfaces and Protocols”, “Service Functions” and

“Networking Mode and System Configuration” or study the manual systematically.

The technical manual is applicable to ZTE softswitch control equipment ZXSS10 SS1a

/1b (V2.0). In actual applications, if the manual differs from the actual system version,

the contents in the actual version should apply.

Related manuals also include:

ZXSS10 SS1a/1b (V2.0) Softswitch Control Equipment Operation Manual

ZXSS10 SS1a/1b (V2.0) Softswitch Control Equipment Maintenance Manual

ZXSS10 SS1a/1b (V2.0) Softswitch Control Equipment Installation Manual-Hardware

SS1a/1b (V2.0) Softswitch Control Equipment Installation Manual-Software

ZXSS10 SS1a/1b (V2.0) Softswitch Control Equipment Hardware Manual

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Contents

1 Basic Knowledge ......................................................................................................................................1-1

1.1 Basic Conceptions of Data Communication ..................................................................................1-1

1.2 Network Switching Technology.....................................................................................................1-5

1.3 Packet Switching............................................................................................................................1-7

1.4 IP Telephony Technology...............................................................................................................1-8

1.5 Common IP Voice Coding and Compression Modes .....................................................................1-9

1.6 IP Address ....................................................................................................................................1-10

2 System Overview ......................................................................................................................................2-1

2.1 System Introduction .......................................................................................................................2-1

2.1.1 Background of Softswitch...................................................................................................2-1

2.1.2 ZXSS10 Softswitch Architecture ........................................................................................2-2

2.2 Architecture....................................................................................................................................2-4

2.2.1 Hardware Structure .............................................................................................................2-4

2.2.2 Software Structure...............................................................................................................2-4

2.3 Operating Principles of ZXSS10 SS1a/1b System......................................................................2-6

2.4 System Functions ...........................................................................................................................2-7

2.5 System Features ........................................................................................................................... 2-11

2.6 Main Functions and Applicable Scope.........................................................................................2-14

2.7 Working Conditions .....................................................................................................................2-15

3 Technical Indices.......................................................................................................................................3-1

3.1 Processing Capability.....................................................................................................................3-1

3.1.1 BHCA..................................................................................................................................3-1

3.1.2 Maximum Subscriber Capacity of System..........................................................................3-1

3.1.3 System Expansion ...............................................................................................................3-2

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3.1.4 Others.................................................................................................................................. 3-2

3.2 Charging Performance ................................................................................................................... 3-2

3.3 Time Monitoring and Load Capacity............................................................................................. 3-2

3.4 Reliability and Availability ............................................................................................................ 3-3

4 Interfaces and Protocols............................................................................................................................ 4-1

4.1 Overview ....................................................................................................................................... 4-1

4.2 Physical Interface........................................................................................................................... 4-1

4.3 Protocol Interface........................................................................................................................... 4-1

5 Service Functions ..................................................................................................................................... 5-1

5.1 Overview ....................................................................................................................................... 5-1

5.2 Basic Voice Service ....................................................................................................................... 5-3

5.2.1 Basic PSTN Voice Service and Supplementary Service ..................................................... 5-3

5.2.2 IP Centrex ........................................................................................................................... 5-9

5.2.3 IP Public Phone................................................................................................................. 5-14

5.3 Traditional Intelligent Service ..................................................................................................... 5-17

5.4 IP Value-added Service ................................................................................................................ 5-19

5.5 Multimedia Service...................................................................................................................... 5-20

6 Networking Mode and System Configuration .......................................................................................... 6-1

6.1 Networking Mode.......................................................................................................................... 6-1

6.1.1 Networking Mode of Backbone Network........................................................................... 6-1

6.1.2 Networking Mode of Local Network.................................................................................. 6-2

6.2 System Configuration .................................................................................................................... 6-6

AppendixA Analysis of Common Technical Indices .................................................................................. A-1

A.1 Delay Analysis ............................................................................................................................. A-1

A.2 Traffic Analysis............................................................................................................................ A-3

A.2.1 Network Traffic Analysis .................................................................................................. A-3

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A.2.2 Traffic Analysis of Softswitch Control Equipment ...........................................................A-5

AppendixB ZXSS10 SS1a/1b Protocol Stack............................................................................................. B-1

B.1 Megaco/H248 Protocol................................................................................................................. B-1

B.2 MGCP Protocol ............................................................................................................................ B-2

B.3 SCTP Protocol .............................................................................................................................. B-3

B.4 M3UA Protocol ............................................................................................................................ B-4

B.5 SIP Protocol.................................................................................................................................. B-6

B.6 No.7 UP Protocol.......................................................................................................................... B-7

AppendixC Abbreviations........................................................................................................................... C-1

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A List of Figures

Fig. 1.2-1 A Simple Communication Network .........................................................................................1-6

Fig. 1.3-1 Packet .......................................................................................................................................1-7

Fig. 2.1-1 Next-generation Network Based on the Softswitch Technology..............................................2-2

Fig. 2.2-1 System Architecture Connection of Softswitch Control Equipment ........................................2-4

Fig. 2.2-2 Software System of Softswitch Control Equipment .................................................................2-5

Fig. 2.3-1 ZXSS10 SS1a/1b Platform.......................................................................................................2-6

Fig. 4.3-1 Typical Application of Protocols ..............................................................................................4-2

Fig. 5.1-1 Service Provisioning Mode of Softswitch Network .................................................................5-2

Fig. 5.2-1 Provisioning Mode of IP Centrex Service ..............................................................................5-10

Fig. 5.2-2 Simplified IP Public Phone.....................................................................................................5-15

Fig. 5.2-3 Standard IP Public Phone .......................................................................................................5-16

Fig. 6.1-1 Class 4 Solution........................................................................................................................6-2

Fig. 6.1-2 Solution Integrating Home Data and Voice ..............................................................................6-3

Fig. 6.1-3 Pure Voice Solution of the Office (corridor).............................................................................6-4

Fig. 6.1-4 Community Solution ................................................................................................................6-5

Fig. 6.1-5 Intelligent Terminal Solution....................................................................................................6-6

Fig. B.1-1 Relationship between Transactions, Contexts and Commands............................................... B-2

Fig. B.4-1 M3UA Application.................................................................................................................. B-4

Fig. B.5-1 Typical SIP Session/Call Setup Process.................................................................................. B-6

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A list of Tables

Table 5.2-1 Supplementary Services.........................................................................................................5-3

Table 5.2-2 Centrex Service Functions ...................................................................................................5-10

Table 5.2-3 Functions of Operator Console ............................................................................................5-13

Table 5.3-1 Traditional Intelligent Service..............................................................................................5-18

Table 5.4-1 IP Value-added Service ........................................................................................................5-19

Table 6.1-1 Various Solutions ...................................................................................................................6-2

Table 6.2-1 ZXSS10 SS1a Hardware Configuration List 1 ......................................................................6-7

Table 6.2-2 ZXSS10 SS1b Hardware Configuration List 2 ......................................................................6-8

Table 6.2-3 ZXSS10 SS1a Background Configuration List......................................................................6-8

Table 6.2-4 ZXSS10 SS1b Hardware Configuration List 1 ......................................................................6-9

Table 6.2-5 ZXSS10 SS1b Hardware Configuration List 2 ....................................................................6-10

Table 6.2-6 ZXSS10 SS1b Background Configuration List ................................................................... 6-11

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1 Basic Knowledge

Summary

This chapter describes basic knowledge related to the softswitch product, including the

basic conceptions of data communication, network switching technology, packet

switching, IP telephony technology, common IP voice codes and compression modes as

well as definition of and division principles for IP addresses. To understand the above

basic knowledge can help users to better learn the softswitch technology.

1.1 Basic Conceptions of Data Communication

Data communication is a new communication mode combining the computer and

communication, which is the foundation upon which various computer networks can be

set up. The data communication network has been developing for 30 years. In the

course when human beings enter the information society, data communication is

playing a more and more important role.

There are many conceptual terms involved in data communication. We can actually

grasp the essence of data communication only after understanding these terms.

1. Channel

The path where the transmission information is to pass is called “channel”. In

computers, channels are further divided into physical channels and logic

channels. The physical channel refers to the physical path used to transmit

signals or data. The physical path between two termination points in a network

is called a communication link. A physical channel is composed of transmission

media and relevant devices. The logic channel is also a kind of path. However,

there is no physical transmission media between the signal receiving and

transmitting points. In this case, the transmission is made possible via the “edge”

within the termination on the foundation of the physical channel. Generally, a

logic channel is called as “connection”.

2. Code element


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The code element is known as each bit in binary numbers transmitted over a

network, e.g.: 10101010.

3. Data

There are two types of data: analog data and digital data.

For analog data, both the time and amplitude are continuous. Its level varies

continuously with the time. For example: voices are typical analog signals.

Other signals received by analog sensors such temperature, pressure and traffic

are also analog signals. For digital data, the time is discrete while the amplitude

is quantized. It is generally a numeric sequence composed of binary codes of 0

and 1. In the communication system, signals represented with analog data are

called analog signals will those represented with numeric data are called digital

signals. They can be transformed to each other.

4. Modem

The traditional telephone communication channel is a kind of analog channel

that only transmits voice signals, which cannot directly transmit digital signals

of computers. To utilize the existing analog line for digital signal transmission, it

is required to transform digital signals to analog signals. This process is called

modulation. At the other end, the received analog signals need to be restored to

digital signals. This process is called demodulation. Since data transmission is

bi-directional generally, modulation and demodulation are needed at both ends.

The device performing such functions is called MODEM.

5. Data transmission rate

It refers to the speed of information transmission over the communication line.

The data transmission rate is represented in two ways: signal rate and

modulation rate.

Signal rate S: refers to the valid bits of binary bit codes transmitted in the unit

time. Generally, its unit is bits per second, i.e., BPS.

Modulation rate B: is the transmission rate of modulated pulse signals. Its unit is

BAUD. Generally, it is used to represent the signal transmission rate between

modulators.

The relationship between signal rate S and modulation rate B is: S=B×log2N

Chapter 1 Basic Knowledge

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Here, N indicates the valid status of a pulse signal. In the binary system, there

are two types of status for a pulse: 0 or 1, i.e., n=2. More specifically, signal rate

S is consistent with modulation rate B.

6. Bit error ratio

It refers to the error ratio of the information transmission, which is an index for

judging system reliability. It is measured on the proportion of bits in received

information on the total transmission bits. Generally, the bit error ratio should be

under 10-6.

7. Information capacity

It refers to the highest capability of the channel in information transmission.

Generally, it is represented with the maximum number of information bits that

can be transmitted within the unit time. In actual application, the channel

capacity should be more than the transmission rate. Otherwise, it is impossible

to fully utilize the high transmission rate.

8. Baseband transmission

It refers to transmission of original 0 or 1 digital pulse signals generated by

computers or terminals over communication cables. In this way, the baseband of

a signal can be divided from a direct stream to several MHZs. The broader the

frequency band, the larger the influence of the capacitance and inductance of the

transmission line over waveform attenuation of transmission signals. Generally,

the transmission distance does not exceed 2km. If this distance is exceeded, it is

required to add relays to amplify signals, thus prolonging the transmission

distance.

9. Frequency band transmission

In long-distance communication, it is necessary to modulate digital signals to

audio signals before sending and transmitting them. The receiving end will then

demodulate received audio signals to digital signals. Therefore, when frequency

band transmission is adopted, it is required to mount modems at the transmitting

and receiving ends. This method not only solves the problem of digital signal

transmission over telephone lines but also realizes multi-channel multiplexing

and increasing the channel utilization efficiency.

10. Broadband transmission


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It refers to information transmission via media with higher bandwidth

(approximately 300-400MHz generally). During system design, this frequency

band is split into several sub-bands. With the “multi-channel multiplexing

technology”, multiple types of information such as sounds, images and data can

be transmitted simultaneously over one channel. In this way, the system is made

multipurpose.

11. Serial transmission

It refers to transmission of data bit by bit. In this case, only one transmission line

is needed between the transmitting and receiving ends. The advantage of this

mode is to save devices and reduce expenses. Its disadvantage is that the

transmission rate is low. The application of this transmission mode is

widespread in the current network.

12. Parallel transmission

In this case, one byte (8 bits) is transmitted each time and eight lines are used

between the transmitting and receiving ends.

At present, parallel transmission is generally used for operations within

computers. When the serial transmission is adopted, the transmitting end will

transform the parallel data stream to serial data stream via the parallel/serial

conversion device; while the receiving end will restore them to 8-bit parallel

data via the serial-parallel device.

13. Data exchange mode

Generally, computers in the network exchange data via the public

communication transmission line to increase the utilization efficiency of the

transmission equipment. The switching mode in LAN includes two categories:

line switching and storage switching. In storage switching, the packet switching

and packet group switching are commonly used.

14. Character coding

The data transmitted over the channel appear in the binary bit form. It deals with

how to combine two code elements: 0 and 1 so that they can represent different

data and information.

15. Error correction


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Errors are inevitable during the process or character code transmission and

receiving. How to detect errors in time and further correct them is also an

important topic of research for the digital communication system. The general

solutions include anti-interference coding or correction coding. At present, the

commonly solutions include adding polarity check codes, block codes, cycle

redundancy codes and so on.

16. Protocol

It refers to network communication rules, which define the mode of

communication between two computers via a network.

17. Synchronous transmission

It is a transmission mode with message and packet as the unit. Since a packet

may contain many characters, it can considerably reduce the amount of

information used in synchronization, this increasing the transmission rate. At

present, this transmission mode is adopted in most computer networks.

18. Asynchronous transmission

In this case, the unit of the data to be transmitted is character. Moreover, the

transmitting interval between characters is asynchronous, i.e., the transmitting

time of the next character is irrelevant to that of the previous character.

In the data communication system, according to the permitted transmission direction,

the following three data communication modes can be provided:

1. Simplex communication: data can be transmitted only along a fixed direction,

i.e., the transmission is unidirectional.

2. Semi-duplex communication: data can be transmitted along two directions.

However, at a moment, information can be only transmitted along one direction.

3. Duplex communication: information can be transmitted along two directions

simultaneously. This mode is commonly adopted in computer communication,

which can considerably increase the transmission rate.

1.2 Network Switching Technology

In a wide area, data communication is to transmit data from a source node to the

destination via the intermediate switching node network. Such a switching node does


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not care about contents of data. Its objective is to provide switching facilities for

mobile data between nodes. Fig. 1.2-1 shows a simple network. A termination device

for communication can be called a site. A site can be either a computer, terminal,

telephone or another communication device. A switching device providing

communication is called a node. They form a topology after being connected with each

other via transmission links. Each site can be connected with a node. The collection of

all nodes is called a communication network.

B

F

E

D

C

A

1

5

7

6

32

4

Network node

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Termination

Fig. 1.2-1 A Simple Communication Network

In a switching communication network, the data entering the network from a site via

inter-node switching is sent to the destination after being routed. In Fig. 1.2-1, the data

sent from site A to site F are transmitted to node 4. We can set whether to send them to

the destination via node 5 and 6 or node 7 and 6. From this simple network, we can see

that:

1. Some nodes are only connected to other nodes (e.g.: node 5 and 7). The sole task

of these nodes is to complete internal data exchange. Other nodes are connected

to one or more sites. Except the exchange function, these nodes also receive data

from the connected site and delivers data to the connected site.

2. Generally, the multi-channel multiplexing is adopted for inter-node links. We

can also adopt the frequency division multiplexing (FDM) or time division


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multiplexing (TDM) mode. In addition, the network is not all connected, i.e.,

there is no direct link between each possible node pair. However, it is always

hoped that there are more than one path between each pair of sites to increase

the network reliability.

In the wide area network, two utterly different technologies are adopted: circuit

switching and packet switching. Along the path from the source to destination, there

are distinct differences between the modes of switching information from one line to

another for different nodes. Since the major softswitch bearer network is based on the

packet switching network, we will primarily describe the packet switching mode

below.

1.3 Packet Switching

In the packet switching network, data are transmitted in short packets. The upper limit

for the typical packet length is 1,000 bytes (or octet). If a longer packet is to be sent

from a source site, this packet will be split into a series of shorter packets, as shown in

Fig. 1.3-1. Each packet contains a part of user data (or the whole of a shorter packet)

and some control information. The control information should at least contain routing

information needed by the network for sending packets to the destination. At each node

of a path, packets are received, stored for a short period of time and then transmitted to

the next node. Compared with circuit switching, packet switching has the following

advantages:

User data

Control informationPacket header

Packet

Fig. 1.3-1 Packet


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1. High line efficiency: a single inter-node link can be dynamically shared by

multiple packets. In this case, packets are queued and sent out from the relevant

link as soon as possible. However, in circuit switching, the time on the

inter-node link is allocated in advance with synchronous time division

multi-channel multiplexing. In this case, the time slot allocated to a connection

cannot be occupied by other connections even when it is idle.

2. The packet switching network can implement data rate conversion. In this case,

two sites with different data transmission rates can exchange packets with each

other since each site is connected to its communication node at the respective

rate. However, in circuit switching, the two sites connected with a circuit should

transmit and receive data at the same rate.

3. In a circuit switching network, when the traffic is high, some calls will be

blocked, i.e., the network will reject new connection requests before the load on

the network reduces. However, in a packet switching network, such packets will

still be received but the transmission delay is increased.

4. Priorities are used. If there are many packet queues to be transmitted for a node,

it can transmit packets with higher priorities in precedence. These packets will

have lower delay than those with lower priorities.

Generally, packet switching does not mean to send the whole packet of a user. Instead,

one packet is divided into several packets that can be saved in the memory. This

increases the switching speed. This mode is applicable to interactive data transmission.

According to services provided by the communication subnet for the termination

system, packet switching can be further divided into datagram and virtual circuit

switching.

1.4 IP Telephony Technology

The major objective of the IP telephony technology is to combine the IP network with

the telephony network. Moreover, IP telephones can be used by not only computer

users but also ordinary telephone users. The two networks have different characteristics:

the IP network is a kind of network transmitting data information, in which the packet

switching technology is applied; while the telephone network is a kind of network

transmitting analog voice signals, in which the circuit switching technology is applied.

As we know, the characteristic of circuit switching is that a circuit is occupied


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whenever a call is connected. It will be occupied all along as long as no party hangs up

no matter whether the two parties are talking to each other. Generally, a party is

listening while the other party is talking. Therefore, in this case, at least 50% of the

circuit is not utilized and the circuit utilization ratio is very low. The packet

transmission technology is to divide information data to be transmitted into groups

based on a certain length (i.e., cutting them to “packets”), add an address flag to each

“packet”, and then transmit them in the store-forward mode. In this case, each session

packet does not monopolize a circuit. Instead, it is sent only when the circuit is idle. In

this way, multiple sessions can share one channel asynchronously. Thus, the circuit

utilization ratio is considerably increased. Furthermore, the digital compression

technology is adopted in packet transmission. Therefore, the circuit utilization ratio is

many times higher than that of circuit switching. In addition, the charging mode of

packet transmission is irrelevant to the distance. This tremendously reduces the toll IP

cost.

At present, with the application of multiple QoS-ensuring technologies such as the

queue, priority, RSVP, VPN and MPLS, the IP network technology is developing

towards a higher rate and better QoS. Moreover, with the IP telephone technology, the

communication cost can be saved considerably. This determines its tremendous market

potential. With the driving of the market, more and more research institutes,

international standardization organizations, manufacturers etc. are devoting themselves

to the development of IP-related technologies, thus enabling it to reach the degree of

commercialization.

1.5 Common IP Voice Coding and Compression Modes

The transmission of realtime voices via the IP network is different from that of

ordinary data. In the former case, the relevant application devices must meet the

realtimeness of voices. The voice packet transmission requires the network to provide

sufficient bandwidth in time. Therefore, for most of the current IP networks that do not

provide so high rates, the voice compression technology is the key for implementing IP

voice communication. Now, we will present a brief description of the frequently used

voice coding and compression modes at present:

1. PCM


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Pulse code modulation (PCM) is the earliest digital voice technology, which

does not include any compression algorithm. It transmits voice signals with the

64kbps bandwidth, i.e., taking 8,000 samples per second and acquiring an

8-digit voice signal per sample. PCM is the standard coding mode adopted in

G.711.

2. CELP

Code excited linear prediction (CELP) is the most advanced voice transmission

technology at present. The CELP algorithm is to compare analog signal samples

with curves in the predefined code book; send codes in the code book closest to

these analog signal samples to the receiving end; and regenerate original signals

after comparison again with the code book at the receiving end. The sampling

interval of original signals is very short. Therefore, the regenerated signals are

very close to the original signals after being filtered. CELP is the basis of

numerous advanced patented voice compression modes. Voices can be

compressed to 5.3kbps, 8kbps or 9kbps.

3. CS-ACELP

Conjugate structure algebra code excited linear prediction (CS-ACELP) or

G.729 is the 8kbps voice compression and coding standards of International

Telecommunications Union (ITU). CS-ACELP is a new algorithm, which is able

to encode 8kbps voice signal bit streams (while the rate of ordinary PCM signals

is 64kbps). The bandwidth efficiency is eight times as that of PCM and four

times as that of 32kbps ADPCM. At present, CS-ACELP is the most welcome

voice encoding/decoding plan.

When actually selecting a voice compression algorithm, it is necessary to take various

factors into consideration. For example: the pursue of higher bit rates guarantees sound

voice quality but requires to occupy more system resources. While lower bit rates will

influence voice quality and increase delay. Therefore, to keep better voice quality in the

precondition of lower bit rates is the principle for compression algorithm selection.

1.6 IP Address

For a node in the network, the Internet protocol address (IP address for short) is a logic

address. It is independent from any network hardware and network configuration. It

has the same format no matter the type of the physical network. An IP address is a


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4-byte number, which is actually composed of two parts: the first part is the IP network

No. while the second part is the host No. Generally, such a 4-byte IP address is

separated with small dots, in which each byte is indicated with a decimal number. For

example: for 130.130.71.1, the network No. is 130.130 and the host No. is 71.1.

IP addresses can be divided into five classes, i.e., Class A, Class B, Class C, Class D

and Class E. Indicates with binary codes, the highest bit of Class A addresses is 0; the

highest two bits of Class B addresses are 10; the highest three bits of Class C addresses

are 110; the highest four bits of Class D addresses are 1110; and the highest five bits of

Class E addresses are 11110. Since Class D addresses are only used in special

definition of the host group and Class E addresses are reserved for future use, only one

type in Class A, B and C addresses can be allocated for a specific network.

The IP addressing mechanism allows three types of possible network configuration. IP

addresses are the basis for inter-node communication that uses the IP protocol. This is

true for either the private TCP/IP network or public Internet.

If a user does not hope to add a network to the public Internet, the user can select IP

addresses by forced stipulation. If this method is adopted, the IP addresses for all nodes

on this network should meet the following stipulations:

1. The network No. part of each IP address is the same;

2. The IP address of each node on the network should be sole.

The highest bit 0 of a Class A address and its subsequent 7 bits belong to the network

No. part; while the remaining 24 bits indicate the intra-net host No. In this case, there

may be 126 Class A networks in an interconnected network (network No. ranging

between 1~126. 0 and 127 are reserved). While in a Class A network, there may be

16,000,000 nodes. Therefore, Class A addresses are only used in very large regional

networks, e.g., MLNET in the U.S. and some large-scale commercial networks.

The highest two bits 10 of a Class B address and the subsequent 14 bits belong to the

network No. part; while the remaining 16 bits indicate the intra-net host No. In this

case, there may be about 16,000 Class B networks. While in a Class B network, there

may be more than 65,000 nodes. Class B addresses are generally used in networks

constructed by large institutions and companies.

The highest three bits 110 of a Class C address and the subsequent 21 bits belong to the

network No. part; while the remaining 8 bits indicate the intra-net host no. In this case,


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an interconnected network is allowed to include 2,000,000 Class C networks. In each

Class network, there can be a maximum of 254 nodes. Class C addresses are used in

small-scale institutions and companies.

If you do not like to use the binary system, you can also divide the three types of

networks according to the decimal numbers of the first bytes of IP addresses. Class A

address range between 1~126; Class B addresses range between 128~191; and Class C

addresses range between 192~223.

As in the convention, when the binary codes of the entire network No. part (the first

byte for Class A; the first two bytes of Class B; and the first third bytes for Class C) are

all zeros, the network No. is considered as the local network; when the binary codes of

the host No. part (the last three bytes for Class A; the last two bytes for Class B; and

the last byte of Class C) are all ones, the host No. is considered as the broadcast

address within the local network.

2-1

2 System Overview

Summary

The chapter introduces the overall structure, operating principles, major functions,

characteristics, major purposes and applicable range of the ZXSS10 SS1a/1b softswitch

control equipment system.

2.1 System Introduction

2.1.1 Background of Softswitch

At present, two totally independent networks exist: the PSTN network and data

network, which provide the voice service and basic data service respectively.

Network separation and isolation of operation & maintenance have been keeping the

general network operation & maintenance costs on a high level, and furthermore, a

network cannot provide complicated convergence services, although the network

convergence has been an inevitable trend.

Since a traditional voice network is a closed network with monopolized resources, it

has become a common understanding in the telecom industry that the packet network

(typically, the Internet), with the advantages such as open architecture, low costs and

large scale, will replace the PSTN to become the basic frame of the next generation of

convergence networks and that the construction of the next generation of networks will

be based on current packet networks.

It is necessary for carriers to consider resource utilization and investment protection

during construction of future networks. On one hand, carriers should trace the latest

technologies; and on the other hand, they should try to utilize existing technologies and

resources. Thus, carriers can provide users with large numbers of services

economically and rapidly to make the highest profits, without the need of large-scale

network alteration.

The solution of smooth transition from existing networks to the next generation

networks is the key to the problem. The Softswitch solution based on softswitch

technology is just a mainstream solution to smooth network evolution.


2-2

2.1.2 ZXSS10 Softswitch Architecture

Hierarchical models are adopted for the Softswitch-based next generation network. The

entire network can be divided into four layers: Service Layer, Control Layer, Core

(Transport) Layer and Edge Access Layer, as shown in Fig. 2.1-1.

Service layer

Control layer

�

Core layer

Edge layerTGSG IP

PBXAG NAS MSAG WAG

No.7 Network

IAD

Broadband AccessWireless

IP Router/ATM SwtichCore Packet Network

ZXSS10 SSSoftswitch

SCP DatabaseAAA Server Application Server Policy Server

ZXSS10 SSSoftswitch

PSTN / ISDN

H.323GW

SG: signalling gateway TG: trunk gateway AG: access gateway

NAS: narrow-band access server IAD: integrated access device WAG: wireless access gateway

H.323GW: H.323 gateway IP PBX: IP-based private branch exchange MSAG: multi-service access gateway

Fig. 2.1-1 Next-generation Network Based on the Softswitch Technology

1. The edge access layer refers to various access gateways and new types of access

terminal devices related to the current network. It implements interworking with

the existing various types of communication networks and provides access of

Chapter 2 System Overview

��

various communication terminals (e.g., the analog phone, SIP Phone, PC Phone

visual terminal and intelligent terminal) to the IP core layer.

2. The Core (Transport) Layer refers to a packet switching network composed of

backbone transmission equipment such as IP router or broadband ATM switch,

which is the bearer basis of a softswitch network.

3. The Control Layer refers to Softswitch control units, which completes integrated

control processing functions such as call processing control, access protocol

adaptation, interconnection and interworking and provides an application

support platform for the entire network.

4. The Application Layer provides a network with various applications and

services, client-oriented integrated intelligent services and service

customization.

Where, standard interfaces are used for communication between layers. Under the

control of the core equipment (i.e., the Softswitch control equipment) and based on

division of labor and cooperation of work, the related NE equipment implements

various service functions of the system.

In softswitch architecture, the softswitch control equipment is the core, which is

independent of the bottom-layer bearer protocols and implements functions such as call

control media gateway access control, resource allocation, protocol processing, routing,

authentication and accounting. The softswitch control equipment can provide all basic

call services, supplementary services and point-to-point multimedia services a PSTN

can provide. Furthermore, with the cooperation of the Service Layer equipment (SCP)

and Application Server, the equipment also can provide users with traditional

intelligent services, value-added IP services, diverse third-party value added services

and new intelligent services.

ZXSS10 SS1a is a piece of softswitch control equipment with medium capacity, which

can process hundreds of thousands of calls. ZXSS10 SS1b is a piece of softswitch

control equipment with large capacity, which can process millions of calls.


2-4

2.2 Architecture

2.2.1 Hardware Structure

Compared with a traditional switch, the hardware structure of the softswitch control

equipment is relatively simple, which mainly includes the foreground realtime

processing part, the background (OSS and Database Server) and System Switching

Network (SSN) card interconnection all internal modules. The connection is shown

in Fig. 2.2-1.

DatabaseServer

IP

ZXSS10 SS1a/1b

Real-timeprocessing part

Operation & maintenance terminal

Fig. 2.2-1 System Architecture Connection of Softswitch Control Equipment

ZXSS10 SS1a/1b uses a dedicated hardware platform based on multi-processor cards.

Compared to PC platforms or commercial workstation platforms, ZXSS10 SS1a/1b is

characterized by advantages of large capacity, high density, high reliability and high

cost-performance ratio.

2.2.2 Software Structure

Designed in the distributed mode, the software system of ZXSS10 SS1a/1b has the

hierarchical and modular features. The software system is independent of the specific


��

hardware platform, so the upgrading is very convenient. The schematic diagram is

shown in Fig. 2.2-2.

Softswitch ZTE

ResourceManager

DataBase

Softswitch

Appl. Server

CallServer

BICC/SIP-T

ServiceManager

DataManager

NewDeviceAdapter

H.323DeviceAdapter

SIPDeviceAdapter

H.248DeviceAdapter

No.7DeviceAdapter

SG

SIPPhone

MGAccessServer

H.323GW

NewDevice

SG: signalling gateway MG: media gateway H.323GW: H.323 gateway

Fig. 2.2-2 Software System of Softswitch Control Equipment

Where, the Device (Protocol) Adaptation Layer is responsible for accessing various

external standard protocols such as H.248, MGCP, H.323 and No.7, converting them to

unified internal messages and sending them to the Call Server for proper processing.

For future protocols, we can implement the upgrading of the system smoothly just by

adding the corresponding software adaptation module to this layer.

As the control core of the system, the Call Server provides unified call control. The

Resource Manager is responsible for allocating various call-related media resources,


2-6

for example, controlling the media server to play service tones. The BICC/SIP-T

module supports interworking between peer entities (softswitch control equipment).

The Service Manager is responsible for providing interaction between the softswitch

control equipment and the upper-level SCP and Application Server. The Data Manager

provides a unified access interface to the internal database.

2.3 Operating Principles of ZXSS10 SS1a/1b System

The ZXSS10 SS1a/1b softswitch control equipment uses a dedicated hardware

platform based on the multi-processor card structure and taking high-speed serial data

bus as the core and the Ethernet structure as the foundation. It takes a set of switch

Ethernet bus as the communication and data bus within the system, as shown in Fig.

2.3-1.

Network interface

Network interface

Core switchingnetwork

Protocolprocessor card


System maincontrol

IP network


Fig. 2.3-1 ZXSS10 SS1a/1b Platform

As the system core, a processor module mainly implements core functions such as

network control and service generation. Processor modules are connected via a fast

Ethernet to form a parallel multi-processor system in the "loose coupling" mode. The

main control processor card at the system slot controls each processor card and

allocates different tasks. Multiple processor cards implement mutual communication

and message data forwarding via the Ethernet.

The network interface module provides external interfaces with various gateway

devices via an IP network and internal interfaces with various application servers,


��

database, AAA server, management maintenance terminal and intelligent network SCP.

In consideration of security, the two types of interfaces are physically independent. For

the convenience of networking, the external interfaces can provide the routing function

and configure some static routes so as to guarantee flexible and convenient access to

the IP core network.

2.4 System Functions

ZXSS10 SS1a/1b softswitch control equipment mainly completes the following

functions:

1. Call processing control

The equipment is responsible for completing the basic and enhanced call

processing.

The equipment controls setup, hold call release of basic calls, including call

processing, connection control, intelligent call triggering detection and resource

control. It supports the receiving of monitoring requests from the service

switching function and the processing of the call-related events. ZXSS10

SS1a/1b softswitch control equipment receives the information related to call

control from the service switching function and supports call setup and

monitoring.

ZXSS10 SS1a/1b softswitch control equipment supports basic two-party call

control and multi-party call control. The support of multi-party control functions

includes the control of special logical relationship between multi-party calls,

join/exit/isolation/audit of call members and mixing process. The equipment

also identifies events such as hook-off, dialing and hook-on reported by the

media gateway, controls the media gateway to send various signaling tones

(such as dialing tone, ringing tone, ring-back tone, etc.) to subscribers and

provides dial-up plan meeting the carriers’ requirements.

ZXSS10 SS1a/1b softswitch control equipment can cooperate with a signalling

gateway to complete the setup and release of a complete call. It uses the No.7/IP

protocol and mainly uses the bearer protocol of SCTP. Furthermore, the

equipment can control the media gateway to send IVR so as to implement

various services such as secondary dialing.


2-8

ZXSS10 SS1a/1b softswitch control equipment can be directly connected to

H.248 terminals, MGCP terminals and SIP Client to provide the corresponding

services.

If a ZXSS10 SS1a/1b softswitch control equipment is located on a local

PSTN/ISDN network, it has the call processing function of local telephone

switching equipment. If the softswitch control equipment is located on a

PSTN/ISDN toll network, it has the call processing function of toll telephone

switching equipment.

2. Adaptation of access protocols

ZXSS10 SS1a/1b softswitch control equipment is responsible for adaptation

processing of various access protocols (signaling).

The ZXSS10 SS1a/1b softswitch control equipment is an open and

multi-protocol entity, which communicates with various media gateways,

terminals and networks via standard protocols. These protocols include: H.248,

SCTP, ISUP/IP, TUP/IP, INAP/IP, H.323, RADIUS, SNMP, SIP, M3UA, MGCP

and SIP-T.

3. Service provisioning/interfacing

ZXSS10 SS1a/1b softswitch control equipment can provide services a

PSTN/ISDN switch can provide, including basic services and supplementary

services. The equipment can cooperate with the SCP on an existing intelligent

network to provide services the existing intelligent network can provide; and

also it can cooperate with the Application Server to provide various value-added

services.

ZXSS10 SS1a/1b provides standard INAP interface with an intelligent network

and provides interfaces with an interface with the Application Server for the

convenience of service development of the third-party service provider.

4. Interconnection and interworking

As an external interface of the softswitch system, ZXSS10 SS1a/1b softswitch

control equipment is responsible for completing the interconnection and

interworking with other peers.


��

ZXSS10 SS1a/1b softswitch control equipment supports the application of a

signalling gateway to implement the interworking between an existing packet

network and an existing SS7 network.

ZXSS10 SS1a/1b softswitch control equipment implements interworking with

an existing intelligent network via a media gateway and can provide users with

various intelligent services. The Media Server and media gateway under the

control of ZXSS10 SS1a/1b softswitch control equipment implement functions

such as IVR necessary for intelligent services.

By means of an interworking module and the H.323 protocol, ZXSS10 SS1a/1b

softswitch control equipment implements interworking with an IP telephone

network with the H.323 architecture.

ZXSS10 SS1a/1b softswitch control equipment implements interworking with

future SIP network architecture by means of the SIP protocol.

ZXSS10 SS1a/1b softswitch control equipment implements interworking and

interconnection with softswitch control equipment by means of the SIP-T

protocol.

ZXSS10 SS1a/1b softswitch control equipment supports the interworking

between H.248 terminals, SIP terminals and MGCP terminals in an IP network.

5. Application support

ZXSS10 SS1a/1b supports applications such as accounting, authentication,

operation and maintenance, etc.

ZXSS10 SS1a/1b softswitch control equipment does not provide a billing

system itself, which is only responsible for generating Call Detail Records

(CDRs). If a call ends, the equipment can output the corresponding charging

data immediately. For a call with long duration, the charging data can also be

output during the call.

By means of standard protocols, ZXSS10 SS1a/1b softswitch control equipment

can be connected to the Billing Center to transfer the charging data, i.e., CDRs.

Where, for ordinary services, the Billing Center can use the FTP protocol to

collect the charging data provided by the softswitch equipment periodically (the

minimum periodic data connection period is 5 minutes). For accounting card or

prepaid service, the softswitch control equipment uses the Radius protocol to


2-10

transfer the charging data to the Billing center in real time, with the realtime

disconnection function.

ZXSS10SS1a/1b softswitch control equipment and the accounting system can

transfer subscriber information such as account opening and cancellation via a

standard XML interface.

ZXSS10 SS1a/1b softswitch control equipment supports access authentication of

users and gateway equipment so as to prevent access of unauthorized users and

equipment.

ZXSS10 SS1a/1b softswitch control equipment provides perfect operation &

maintenance and supports local maintenance management. Furthermore,

ZXSS10 SS1a/1b softswitch control equipment supports SNMP-based network

management mechanism and centralized remote network management, which

can be included into the unified management of the network management center

with other NE equipment in the system.

6. Address resolution

ZXSS10 SS1a/1b softswitch control equipment is responsible for the translation

from E.164 addresses into IP addresses and supports the address resolution

function.

7. Voice processing

ZXSS10 SS1a/1b softswitch control equipment can control whether a media

gateway should use voice compression and can provide the optional voice

compression algorithms, such as G.711, G.723 and G.729.

ZXSS10 SS1a/1b softswitch control equipment can control whether a media

gateway should use the echo cancellation technology.

ZXSS10 SS1a/1b softswitch control equipment also can provide the media

gateway with the size of the voice packet buffer so as to reduce the influence of

jitter on voice quality.

8. Resource control

ZXSS10 SS1a/1b softswitch control equipment provides resource management

so as to perform centralized management over various system resources, such as

allocation, release and control of resources.


��

2.5 System Features

In the respect of design, the ZXSS10 SS1a/1b softswitch control equipment uses the

most advanced design method: distributed system design, which not only effectively

reduces the risk in running of the entire system but also increases the processing

capability and efficiency of the system. A dedicated communication equipment

platform serves as the hardware platform of the system and a realtime multi-task

operating system serves as the software platform, which completely guarantees the

requirements of carrier-class operation equipment for large capacity and high reliability.

Therefore, the products have very high cost-performance ratio.

As the core equipment of the next generation of networks, ZXSS10 SS1a/1b softswitch

control equipment is characterized by the following performances:

1. Powerful networking capability

1) With different combinations of ZXSS10 SS1a/1b softswitch control equipment

and gateway equipment, for example, SS + TG + SG, SS + AG and SS + IAD,

different toll networks and local networks can be organized to provide toll

solutions, local solution and integrated toll and local solutions.

2) The system depends upon widely distributed data networks as bearer networks

and supports various network topologies such as start, tree, ring, start + ring, etc.

3) The system has powerful penetration capability and supports various network

scales. Therefore, the system not only can provide services for a large number of

centralized users, but also can expand all services to scattered users on edges of

tones.

4) The system inherits the advantages from existing networks perfectly and

supports the complete interworking with PSTN/ISDN networks, No.7 signaling

networks and mobile communication networks.

5) ZXSS10 SS1a/1b softswitch control equipment provides perfect integrated

Network Management System (NMS) and standard network interfaces so that it

can be connected to the local network management center flexibly and

conveniently. ZXSS10 SS1a/1b provides detailed CDRs and sends the CDRs to

the Billing Center via a standard interface so as to implement centralized

settlement in the Billing Center.

2. Perfect integrated equipment access capability


2-12

1) ZXSS10 SS1a/1b softswitch control equipment supports direct access of various

types of gateway equipment, including trunk gateway, access gateway,

signalling gateway, media gateway, wireless access gateway, integrated access

device, etc.

2) The system supports the direct access of media server.

3) The system supports the direct access of various digital terminal devices such as

PC, Softphone and IP Phone.

4) The system supports policy-based device control, dynamic addition new devices

and dynamic domain adjustment.

5) The system supports the direct access of existing H.323 network devices such as

H.323 gateways and H.323 terminals.

3. Powerful network interworking capability

1) By means of gateway equipment, the system supports the complete interworking

with various existing networks such as PSTN/ISDN networks, No.7 signaling

networks, INs and PLMNs.

2) With the application of standard protocols, the system supports the interworking

between the same or heterogeneous networks among different manufacturers

and carriers.

4. Perfect scalability

1) The system is of a layered (hierarchical) architecture. The layers are mutually

independent and can develop independently.

2) The distributed mode is used in system design so that the system can implement

smooth capacity expansion conveniently.

3) With the plane structure, the system supports the networking mode with

multi-domain expansion so that the user can plan the network construction scale

according to the specific requirements.

5. Powerful service capability

1) With the hierarchical (layered) architecture, the services provided by the system

are independent of the network and media. Once a service is generated, it can be

shared by the entire network.


��

2) As a unified service proxy and service bearer platform, the softswitch control

equipment masks the complexity of the bottom-layer network for the Service

Layer, for the convenience of the generation of complicated integrated services.

3) There are three service provisioning modes: The softswitch control equipment

provides services itself; the equipment cooperates with the traditional SCP to

provide services; and the equipment cooperates with the Application Server to

provide services. Such service provisioning modes completely guarantee that the

system has perfect flexibility in utilizing existing resources and developing

future services and that the user can select and expand services flexibly and

conveniently according to the specific requirements.

6. Perfect manageability and operability

1) The equipment provides an integrated NMS, supports three interface modes

(GUI, CLI and WEB) and can implement network management functions such

as centralized maintenance, network management, fault management and static

configuration management.

2) The system provides complete operation & maintenance functions for itself,

including Element Management System (EMS) functions such as CLI, authority

management, log, traffic statistics, signaling tracing, SNMP, data configuration,

alarm and diagnosis test. The system has the features of good openness, perfect

performance, high security and rich functions, and furthermore, it can provide

detailed CDRs to that the Billing Center can perform centralized charging. The

system uses a large network database as its data platform and provides multiple

charging data backup modes, so as to guarantee the security of charging data and

fully meet the actual requirements of telecom operation.

7. High reliability

1) With respect to hardware design, the equipment provides hot backup for all

important components and all cards support hot swap with full fault tolerance

consideration, so as to guarantee that no single-point fault will occur during the

running.

2) The redundant active/standby mode or distributed cluster mode (even the remote

fault tolerance mode) is used in equipment networking. The components in each

key system are also redundant and host swappable.


2-14

3) As for software, the equipment provides hot backup for all important data. If the

active system fails, the standby system will take over all calls under

conversation and ringing, complete the calls and save the call records.

4) The system the requirement for 99.99% reliability of carrier-class equipment.

8. Security

1) Network security

The system supports setting of different levels of administrator authority, thus

preventing users from conducting excessive operations on the equipment. For

users attempting to enter the system illegally, the background maintenance

terminal provides realtime LOG information records. For requests that have

hidden threats to the equipment, such as repeated authentication failures,

dangerous IP address connections and concurrent large traffic, graphic alarm

prompts will be given. In addition, ZXSS10 SS1a/1b provides some built-in

self-test security tools, thus automatically rejecting doubtful invasions and

reporting them to the system.

2) User security

The ZTE softswitch system provides an equipment authentication code for each

valid device whose access is permitted. It judges whether to access a subscriber

via an authentication code.

2.6 Main Functions and Applicable Scope

A network based on softswitch technology has the basic features of a Next Generation

Network (NGN), which can provide integrated multimedia services such as data, voice

and video in a centralized manner. The current versions of softswitch systems provide

voice-related services and IP value-added services, including:

1. Local service on Metropolitan Area Network (MAN)

2. Network and service interworking with existing PSTN and IN.

3. Toll service on backbone data networks

4. WEB-based IP value-added service.

Furthermore, these systems also can provide point-to-point multimedia communication

services.


��

In the above various applications, ZXSS10 SS1a/1b softswitch control equipment, as

the control core of the system, is responsible for processing basic functions such as call

control, protocol adaptation and resource management. And furthermore, as the

charging collection point of the system, the equipment provides CDRs of all calls

serving as the basis of the Billing System.

2.7 Working Conditions

Packet switching (packets) networks are the bearer basis of Softswitch networks, which

are responsible for forwarding and routing of all information. Same as routers and

ATM switches, ZXSS10 SS1a/1b softswitch control equipment and other related

devices such as media gateway, signalling gateway, Application Server, media Server

are nodes on packet networks and are connected via widely distributed packet

networks.

ZTE softswitch system ZXSS10 provides IP-based solutions. All packet networks

bearing IP services and the related technologies can serve as the bearer basis of

Softswitch networks, such as IP over ATM, IP over FR, IP over SDH and IP over

DWDM.

To construct an integrated service network based on ZXSS10 series equipment, first

build perfect packet networks supporting IP services. In actual construction, the

construction of a packet switching network can be synchronized with that of a

Softswitch integrated service network.

3-1

3 Technical Indices

Summary

This chapter introduces such technical indices as the processing capability, charging

performance, time monitoring, loading capability, reliability and availability.

3.1 Processing Capability

3.1.1 BHCA

A single frame of ZXSS10 SS1a softswitch control equipment with medium capacity

supports 500K BHCAs.

A single frame of ZXSS10 SS1a softswitch control equipment with large capacity

supports 2000K BHCAs, and the cascading of three frames can support a maximum of

6000K BHCAs.

3.1.2 Maximum Subscriber Capacity of System

If the processing capability is given, the maximum number of digital trunks depends

upon the specific traffic model.

When the average traffic on busy per trunk is 0.7Erl and the average traffic on busy per

subscriber is 0.1Erl:

ZXSS10 SS1b is a kind of large-capacity softswitch control equipment. According to

the above traffic model, it can be estimated that the system provides the processing

capability of a maximum of 200,000 trunks or 2,000,000 subscribers.

ZXSS10 SS1a is a kind of softswitch control equipment with media capacity launched

for medium/small-capacity networks or enterprise/industry users in the current market.

Under the same traffic model, the equipment provides the processing capability of

30,000 trunks or 300,000 subscribers, thus sufficiently meeting the network

construction demands of telecom carriers.


3-2

3.1.3 System Expansion

ZXSS10 SS1a is a kind of medium capacity softswitch control equipment and ZXSS10

SS1b is a kind of large capacity softswitch control equipment. If SS1a cannot meet the

capacity requirements, it is recommended that ZXSS10 SS1b be used directly. By

configuration of different numbers of cards (SPCs), SS1b can provide a processing

capacity ranging from hundreds of thousands of subscribers to several million

subscribers. In full configuration, SS1b can process two million subscribers. If

necessary, frame expansion can be used to further improve its processing capability.

ZXSS10 SS1b supports cascading of three frames.

3.1.4 Others

The equipment supports 60 parties to attend the same conference at maximum.

3.2 Charging Performance

The major charging performance indices are as follows:

1. Charging error ratio: <10-4;

2. Charging precision: 10ms;

3. Correctness ratio: charging correctness ratio ƒ99.96%;

4. CDR processing capability: ƒ10 million CDRs/month;

5. Charging data storage capability ƒ10 million CDRS (If the charging database

ƒ15G and the file storage space ƒ6G);

6. Charging data buffer capability ƒ1 million CDRs.

3.3 Time Monitoring and Load Capacity

The indices of the time monitoring and load capacity are as follows:

1. No dialing after hook-off time supervision: 10 seconds

2. Digit interval no dialing time supervision: 20 seconds (adjustable)

3. Long time no reply time supervision of local calls: 60 seconds

4. Long time no reply time supervision of toll calls: 90 seconds

5. Long time no reply time supervision of international toll calls: 120 seconds

Chapter 3 Technical Indices

��

6. Howler tone time supervision: 40 seconds

7. The time for listening the busy tone is 40s (adjustable).

3.4 Reliability and Availability

ZXSS10 SS1a/1b softswitch control equipment is a carrier-class product. All major

hardware boards support active/standby hot backup and power-on hot

plugging/unplugging. It meets the 99.999% reliability requirements of carrier-class

equipment and the maximum fault time per year is less than 5.3 minutes.

The complete boot time of ZXSS10 SS1a/1b softswitch control equipment includes

version load time and data load time. Where, the data load time is closely related to the

specific data volume (please do not treat all data load times as the same). Normally, the

version load time is less than two minutes.

4-1

4 Interfaces and Protocols

Summary

This chapter introduces the connection of the product with the entire network, the

provided internal/external interfaces and used signalling/protocols. It enables users to

have a full understanding of the connection modes of the equipment and other

products.

4.1 Overview

The ZXSS10 SS1a/1b softswitch control equipment is the control core in the softswitch

system, which also serves as the external interface of the entire system. SS1a supports

multiple signaling protocols, which can provide interactions with other networks such

as PSTN, H.323 and SIP.

In addition, as an NE in the packet network, the SS1a/1b softswitch control equipment

also provides the Ethernet interface for connection with the data network.

4.2 Physical Interface

The 100Base-T Ethernet (RJ 45) interface serves as the interface between the ZXSS10

SS1a/1b softswitch control equipment and data network.

It complies with the Ethernet standards of IEEE802.3 and IEEE 802.3u.

4.3 Protocol Interface

The ZXSS10 SS1a/1b softswitch control equipment is a multi-protocol entity, which

interacts and coordinates with other NEs in the softswitch network via various standard

protocols (interfaces) to perform functions needed in the system together.

The ZXSS10 SS1a/1b softswitch control equipment supports the following protocols:

1. Call processing protocol

ISUP, TUP over IP, SIP-T and H.323

2. Transmission control protocol


4-2

TCP, UDP, SCTP and TCAP/SCCP/M3UA

3. Media control protocol

H.248, SIP and MGCP

4. Service application protocol

INAP (CS2), LDAP and RADIUS

5. Maintenance management protocol

SNMP

The typical application of various protocols is shown is shown in Fig. 4.3-1.

SCP

App Server

Softswitch Softswitch

IP Core Network

AAA Server

SG MG MG

IAD

INAP/TCAP

ISUP/MTP

ISUP/IPINAP/TCAP/IP

SIP-T

TDMTDM

H.248

API/SIP

H.248/MGCP

H.323GW

SIP

H.323

NMS

SNMP

SNMP

SNMP

Computer SIP Phone

No.7 Network

PSTN/ISDN

Control and signalling stream

SNMP

Radius

Media and control stream

ComputerTelephone

Telephone

Telephone Computer

1 2 3

4 5 6

7 8 9

* 8 #

SG: signaling gateway MG: media gateway IAD: integrated access device

H.323GW: H.323 gateway AAA: AAA server

Fig. 4.3-1 Typical Application of Protocols

5-1

5 Service Functions

Summary

This chapter introduces various functions implemented by the product. It presents a

detailed description of various functions and their implementation so that users can

understand service functions provided by the system.

5.1 Overview

The ZXSS10 SS1a/1b softswitch control equipment has powerful service capability.

The system is designed with the hierarchical network framework (as shown in Fig.

5.1-1). The service provisioning is independent from the network and media. Once the

service is generated, it will be shared by the entire network. The flexible service logic

creation environment enables carriers to avoid dear hardware upgrade costs and

relevant technology and transportation costs when launching new services. Services

can be provided flexibly by developers, carriers or soft corporations authorized by

carriers and the third party. Compared with the traditional method, carriers are able to

launch new services more quickly without lower costs.


5-2

SCP

Parlay GW

Softswitch Softswitch

IP Core Network

App Server

SG MG MG

Telephone

IAD

Computer

Telephone

INAP/TCAP

ISUP/MTP

ISUP/IPINAP/TCAP/IP

API/SIP

SIP-T

TDM

TDM

H.248

Third Party Server

H.248/MGCP

Computer

Telephone

ComputerNo.7 Network

PSTN/ISDN

Telephone Signalling stream

Media stream

H.248H.248

App Server

Parlay/Corba

Parlay/Corba

SG: signalling gateway MG: media gateway Parlay GW: Parlay gateway IAD: integrated access device

Fig. 5.1-1 Service Provisioning Mode of Softswitch Network

The ZXSS10 SS1a/1b softswitch control equipment supports three service provisioning

modes:

1. The ZXSS10 SS1a/1b softswitch control equipment directly provides the basic

PSTN service, supplementary service and point-to-point service video service;

2. The equipment acts as the virtual SSP via interworking with existing SCP to

provide the traditional intelligent service.

The softswitch control equipment provides two modes for interworking with

SCP:

1) Interworking with SCP via SG in the standard No.7 mode;

2) Direct interworking with SCP via the extended INAP protocol on the basis of the

TCP/IP connection.

Chapter 5 Service Functions

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3. The equipment provides the IP value-added service, intelligent service and

future multimedia service by means of supporting the application server.

The WEB Server is added into the network, which acts as the service registration and

selection platform for IP subscribers and the service subscriber window. In the specific

application, the standard service API interface of the application server can be provided

for a third party developer, who can incessantly develop various new services for

subscribers. The application server can also be leased to enterprise group users, who

can provide customized services for subscribers. Moreover, the application server can

be provided for network carriers as the value-added service platform.

5.2 Basic Voice Service

The basic voice service refers to the service of which the major purpose is to ensure

normal conversation between subscribers. It is a service collection instead of a specific

service. It includes the basic call service, basic PSTN voice service and such voice

services as the supplementary service and traditional intelligent service.

Here, the basic call service refers to the local, domestic and international automatic

incoming call and outgoing call services of various terminals. The terminal type

includes the ordinary phone accessed via IAD, Soft Phone and various IP Phones based

on H.248, MGCP, SIP and H.323. The basic call service is provided by the softswitch

control equipment independently.

5.2.1 Basic PSTN Voice Service and Supplementary Service

The ZXSS10 SS1a/1b softswitch control equipment can provide all basic PSTN voice

services and supplementary services specified in YDN 065-1997 Overall Technical

Specifications for Telephone Switching Equipment of MPT and its supplementary

specifications. The supplementary services are shown in Table 5.2-1.

Table 5.2-1 Supplementary Services

Service Name Service Description

Call forwarding

Automatically forward calls to this phone to the temporarily specified

phone set. According to actual needs of subscribers, four services can

be provided: call forwarding on busy, call forwarding on no reply,

call forwarding unconditional (forwarding of all calls) and call


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forwarding on subscriber offline.

Toll prohibited in call

forwarding

After registering call forwarding, a subscriber can use this service so

that calls are not forwarded to toll numbers. This service needs to be

used together with call forwarding.

Forwarding of incoming

toll prohibited

After registering call forwarding, a subscriber can use this service so

that incoming calls other than tolls are forwarded while incoming

tolls are intercepted. This service needs to be used together with call

forwarding.

Call registering on busy

When a subscriber calls another subscriber but the called party is

busy, the call can be recorded. Within 20 minutes, if the subscriber

wants to call that subscriber again, the subscriber just needs to pick

up the phone and wait for 5 seconds without dialing any number to

call that subscriber automatically.

Callback on busy

When the called party is busy, the caller can hang up and wait

without dialing any number. Once the phone of the called party is

idle, automatic callback will be available.

CW

It is permitted that a subscriber in conversation is notified of an

incoming call. The subscriber can select to accept or ignore this

waiting call. After accepting it, the subscriber can switch

conversation between these two callers. In this case, one caller will be

held (hearing the waiting music). In addition, the subscriber can also

interrupt the conversation with a caller and only converse with the

other caller.

Absent subscriber service

When there is an incoming call but the subscriber is out, the office

can provide a voice service to reply the call for the subscriber so as to

avoid repeated dialing of the caller.

Do not disturb

When the subscriber does not hope to reply any call, the office can

reply all incoming calls for the subscriber. Moreover, outgoing calls

of the subscriber will not be affected.

"Do not disturb" in

limited time

With this service, the subscriber can be exempt from interference of

outside calls within 12 hours (adjustable for the equipment buyer).

Moreover, outgoing calls of the subscriber will not be restricted.

Malicious call tracing

When being annoyed by an unknown malicious call, a subscriber can

query the number of the malicious call from the office simply by key

pressing.

Instant malicious call

It is a supplementary for the service of look for malicious calls. With

this service, all incoming calls will be recorded in alarms of the

equipment buyer.

Multi-subscriber number The analog subscriber is provided with the MSN function. In


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addition, there are different rings for different numbers.

Transfer service

When a subscriber is in conversation with the called party, the called

party can be held and another subscriber can be dialed so that the

latter two subscribers can converse with each other.

Three-party conversation

When two subscribers are in conversation, another subscriber can be

dialed without interrupting the conversation between these two

subscribers. Thus, the three-party conversation or conversation with

two subscribers respectively is available.

Telephone conference

The softswitch control equipment provides the service of

simultaneous conversation of more than three parties. When the

telephone conference service is used, the chair subscriber can dial

multiple subscribers (60 at most) continuously so that they can

participate in the conference by pressing the hook.

Virtual conference

In the data of the softswitch control equipment, virtual conference

access codes can be set, including the password, maximum access

number, start and end time. When such conference is used, subscriber

A dials the virtual conference number and inputs the password after

hearing the password input prompt to create a virtual conference

room. Then, this subscriber can hear the notification voice of "Your

are the first to enter the conference room", subscriber B picks up the

phone, dials the virtual conference number after hearing the dial tone,

and input the password after hearing the password input prompt for

access to the conference room. Then, the subscriber can hear the

notification voice of "You have entered the conference room". Then,

subscriber A and subscriber B can converse with each other. In this

case, other subscribers can dial the virtual conference number to enter

the conference room and participate in the conference.

IP Centrex Please refer to 5.2.2 for details.

Abbreviated dialing

It is a service that uses 1~2 user-defined codes to substitute for the

telephone number with many digits. This service can be applied to

dial either the domestic (local) number or direct

domestic/international toll number.

Calling Line

Identification

Presentation

When there is an incoming call, the LCD of the phone of the called

party can automatically display and store the incoming number.

Calling Line

Identification Restriction

It is prohibited to display the phone number of the subscriber for the

called party. The priority of this service is higher than the calling

number display service.

Immediate hotline A subscriber can set the phone number used most frequently as the

hotline (only one hotline is permitted). After application of this


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service, the subscriber will be automatically connected to a fixed

number immediately after hook-off.

Delayed hotline

A subscriber can set the phone number used most frequently as the

hotline (only one hotline is permitted). With this service, the

subscriber will be automatically connected to the phone number set

as "hotline" if not dialing any number within t he specified time (5

seconds) after hook-off.

Call override

After this service is applied, if the called party has registered the "do

not disturb”, absent subscriber or call forwarding service, normal

ringing is available too.

Emergency call override

This function permits the call restricted phone set to dial emergency

calls. This service is valid for all subscribers and needs no special

application.

Secretary service

After subscriber A activates this service, call incoming calls to

subscriber A will be first connected to another specified subscriber B.

After being filtered via subscriber B, the calls can be forwarded to

subscriber A again with the call forwarding function or processed by

subscriber B directly. One subscriber B can correspond to multiple

subscriber As. Subscriber B provides the override function for the

secretary service of subscriber A, i.e.: calls from B to A will be

directly connected to A.

Alarm clock service The phone set can ring automatically according to the preset time.

Missing number

If a subscriber has registered the missing number service, when there

is any missing call for the subscriber, the subscriber will hear "You

have XX missing calls. Please dial #*99 to query them." after

hook-off.

Forced disconnection

service

After the subscriber registers the forced disconnection service, the

phone set of the subscriber will have the forced disconnection

function.

Automatic locking in

outgoing call restriction

This service should be used together with the outgoing call

restriction. After applying for the outgoing call restriction, to dial a

restricted number, a user just needs to dial *#66* S1S2S3S4*

(call-out number #). It is unnecessary to dial #54*KS1S2S3S4#

to cancel the call-out restriction. The restricted number will still be

valid after hook-on.

Call-out restriction

This service is used to restrict some outgoing calls of this phone. It

enables the subscriber to restrict some specific outgoing call

functions of the phone set with some simple operations when leaving

the phone set so as to avoid unauthorized use of the phone.

Restriction to specified Incoming calls of subscribers for whom the function of restriction to


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called destination number specified called destination number has been activated will not be

restricted. A maximum of ten destination numbers can be defined in

the restriction list of each subscriber. The destination number can be

the prefix, country code, toll area code, office code, special service

number or subscriber number (with the maximum length of 40

digits). In addition, emergency calls of subscribers for whom the

function of restriction to specified called destination number has been

activated will not be restricted too. The proportion of such

subscribers is 10%.

Connection of specified

called destination number

This service allows a subscriber to only call specified called

destination numbers and incoming calls of this subscriber will not be

restricted. The incoming call of this subscriber will not be affected.

Up to 10 destination codes may be defined in the list of designated

destination code connections. The destination codes may be prefix,

country code, trunk area code, office code, special service number or

subscriber number (with the maximum length of 40 digits). The

emergency call of the subscriber for which designated destination

code connection service is activated is not restricted. The percentage

of the subscribers with the authority for designated destination code

connection service is 10%.

Restriction to specified


This service allows a subscriber to restrict incoming calls from

specified calling destination numbers but outgoing calls of this

subscriber will not restricted. The incoming call of this subscriber

will not be affected. Up to 10 destination codes may be defined in the

list of designated destination code connections. The destination codes

may be prefix, country code, trunk area code, office code, special

service number or subscriber number (with the maximum length of

40 digits). The emergency call of the subscriber for which designated

destination code connection service is activated is not restricted. The

percentage of the subscribers with the authority for designated

destination code connection service is 10%.

Connection of specified


This service allows a subscriber to only connect specified calling

destination numbers and outgoing calls of this subscriber will not be

restricted. The incoming call of this subscriber will not be affected.

Up to 10 destination codes may be defined in the list of designated

destination code connections. The destination codes may be prefix,

country code, trunk area code, office code, special service number or

subscriber number (with the maximum length of 40 digits). The

emergency call of the subscriber for which designated destination

code connection service is activated is not restricted. The percentage

of the subscribers with the authority for designated destination code


5-8


connection service is 10%.

Overriding subscriber

Subscribers can apply for this performance in advance from the

exchange when needing it. For this service, a service reservation flag

is set in the background database. It performs the functions of number

display and malicious call tracing.

Voice announcement for

failed calls

Subscribers can apply for this performance in advance from the

exchange when needing it. For this service, a service reservation flag

is set in the background database. When a call fails, the

corresponding failure voice can be sent to the subscriber.

Not in service A service reservation flag is set in the background database. Any

subscriber dialing this number will hear a voice prompt.

Number reservation after

temporary clear

A service reservation flag is set in the background database of the

exchange. Any subscriber dialing this number will hear the voice

prompt of "Sorry, the service of number reservation after temporary

clear has been registered for this phone!"

Call filter with

black/white list

This service is to prohibit/permit calls from some callers or incoming

calls from a certain incoming trunk to some destination codes

according to the calling numbers or incoming trunk IDs. A destination

code can be a prefix, country code, toll area code, office code, special

service code or phone number. Its maximum length is 20 digits.

Set as computer console

After a subscriber applies for "set as computer console", the

subscriber can be activated only after the telecom office assign the

subscriber with the corresponding authority. Separate use of this

service is meaningless.

Authentication function

1. One of its purposes is to authenticate calls of subscribers under a

carrier. The authentication content includes authorities in using the

network and various services.

2. Another purpose is to authenticate calls from networks of other

carriers so as to judge whether such subscribers have to right to use

services of this network, including the domestic full automatic

service and international full automatic service or other services of

this network.

Interception function

1. For local subscribers, its purpose is to intercept prohibited calls and

send the corresponding recorded announcements according to

subscriber attributes and numbers dialed by subscribers;

2. Another purpose is to intercept inter-network calls after check of

the black/white list;

3. Another purpose is to intercept calls after authentication;

4. The other purpose of this function is to intercept incoming calls

with incomplete calling numbers or without calling numbers.


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Polarity reversal function

Its purpose is to notify the gateway and IAD and provide the

corresponding polarity reversal pulse so as to facilitate the public

phone charging.

Interception service

This service is to automatically intercept calls in case of

vacant/changed numbers, temporary blocking of a route or improper

use by users. Then, such calls will be forwarded to a record pick-up

device for reply, thus reducing false connections. This service is

free of charge and needs no special application.

## Automatic number

report

117 time inquiry service

The subscriber has the

right to preset or select a

carrier based on calls.

For preset subscribers, the softswitch control equipment provides the

capability of free selection or prohibition of free selection.

5.2.2 IP Centrex

ZTE softswitch control equipment ZXSS10 SS1a/1b can provide the IP Centrex service.

Besides all service functions of the traditional CENTREX, it can also provide

extension subscribers with new services specific to the softswitch system so as to meet

requirements for data communication. In terms of networking, it can provide some

functions unavailable in the traditional switching system. It supports CENTREX

application modes crossing offices, regions, equipment of other manufacturers and

multiple types of terminals.

The IP Centrex service is a high-quality service provided by the softswitch control

equipment, which is applicable to enterprise users at various scales. It can replace the

traditional PBX or be used to enhance the traditional telephone service of the existing

PBX. Besides the traditional "*#" plus numeral service application mode, ZTE

softswitch control equipment can also provide the WEB-based service and self-help

management mode. Subscribers can subscribe for or cancel services via the WEB page,

which is very convenient.

The provisioning mode of the IP Centrex service is shown in Fig. 5.2-1.


5-10

IP network

Softswitch

B: 2002 D: 3002A: 2001 C: 3001

B: 1002

A: 1001

City A City B

B:102A: 101

Centrex 2

Centrex 3

Centrex 1

AGAG IADIAD

PBXIAD

PRI /TRK

PSTN

TGNo.7

SG

IADIAD

C:103

IP Phone

Switch

TG

F: 5001 G: 5002City C

IADIAD

C: 1101

D: 1102

Fig. 5.2-1 Provisioning Mode of IP Centrex Service

The IP Centrex of ZTE softswitch control equipment can provide all functions

available in the traditional Centrex, as shown in Table 5.2-2:

Table 5.2-2 Centrex Service Functions

Service Name Service Functions

Intra-group call Subscribers within the same group can directly dial the extension

numbers. The called extensions can be set with special ringing tones.

Out-group incoming call

1. Out-group subscribers can directly call extension subscribers within

the group. The called extensions provide ordinary ringing. Moreover,

extensions can be set with external call restriction.

Operators can transfer external calls. 2. With the incoming call

transfer function, calls can be transferred from any extension to

another extension. If the transfer fails, the original calls should be

transferred back.

External calls can be automatically transferred via the computer

console.

Intra-group outgoing call Extensions can be connected to out-group numbers after the external

access code is dialed without transfer by operators. Extensions can be


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set with restriction to out-group call origination. Subscribers can

either dial number continuously after dialing the external indicating

number or perform dual-stage dialing (dial the subsequent number

after hearing the dial tone). The specific mode can be set according to

actual needs.

Call origination or

acceptance prohibition

Every extension can be set with call acceptance or origination

prohibition.

Phone set locking

Incoming call transfer For intra-group or out-group calls, subscribers can transfer incoming

calls by means of pressing hook.

Co-group pick-up Extensions within a subscriber group can pick up incoming calls to

any other extensions in the same group.

Designated pick-up When an extension A in a group is ringing, extension B within the

same group can pick up incoming calls to extension A.

Secretary service Secretary boards can be designated to pick up calls to bosses and call

back.

Secretary board service

Generally, heads of institutions do not want to hear all calls. After this

service is registered, all calls to them will be first transferred to

secretary phones and then secretaries will ask heads for instructions of

whether to hear these calls (in this case, callers will hear music).

Operator

Centrex subscriber groups can be set with operators. Out-group

subscribers can call the indicating number of a Centrex subscriber

group for connection to the operator of this group. Intra-group

subscribers can dial a specified number to call the operator.

Attendant Login

Operator cancellation

Computer voice console

It can provide subscribers with voice prompts during automatic call

handling, and then instruct subscribers to perform various service

functions based on subscribers’ operations according to the voice

prompts.

Emergency override

Operators are provided with the emergency override function. After

this function is started, the following services of intra-group

extensions can be overridden and the extension subscribers can be

dialed directly: call transfer, absent subscriber service, do not disturb

and incoming call restriction.

Query of missing calls After this service is registered, the system will give the number of


5-12




missing calls in voice announcements when subscribers pick up

phones. Subscribers can query the time of missing calls and calling

numbers according to voice navigation.

Closed-user group Only intra-group dialing instead of call-out is allowed.

Abbreviated dialing Please refer to 5.2.1.

Calling Line Identification

Presentation Its function is to display incoming call numbers on LCD of phones.

Hotline phone It provides the immediate hotline and delayed hotline function.

Call-out restriction A level is added into the user authorities: out-group call-out

restriction.

"Do not disturb" service Please refer to 5.2.1.

Alarm clock service Please refer to 5.2.1.

Interception service

When a subscriber calls a vacant number, the called number has

changed, a route is blocked temporarily or the subscriber uses the

service inappropriately, such calls will be intercepted automatically

and forwarded to the voice pick-up device for reply.

CW Please refer to 5.2.1.

Malicious call tracing

1. The calling number can be traced within 30 seconds after the caller

hangs up;

2. If the caller does not hang up, the called part can continue to talk to

the caller after tracing the calling number;

3. The calling number can be either intra-group or out-group.

Call forwarding

unconditional Please refer to 5.2.1.

Call forwarding on busy Please refer to 5.2.1.

Call forwarding on no

reply Please refer to 5.2.1.

Callback on busy Please refer to 5.2.1.

Three-party conversation Please refer to 5.2.1.

Call registration on busy Please refer to 5.2.1.

Absent subscriber service Please refer to 5.2.1.

Telephone conference Please refer to 5.2.1.


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ZTE softswitch control equipment ZXSS10 SS1a/1b can also provide standard and

simple operator console functions.

Here, the simple operator console is not equipped with any special device. One or some

computers can be specified to act as operators of a Centrex subscriber group. Such

operators can use the incoming call transfer function to perform simple operator

functions, who can forward out-group incoming calls to intra-group extensions or assist

intra-group extensions to call out-group subscribers (including toll agent).

The standard operator console is equipped with special devices, including ACD and the

agent group. ACD is responsible for queuing of specific calls, which can distribute

calls to various agents. The agent includes the ordinary operator agent and monitor’s

agent. The monitor’s agent provides the management function.

The standard operator console can provide functions shown in Table 5.2-3:

Table 5.2-3 Functions of Operator Console


Automatic queuing and

call distribution

Its purpose is to automatically arrange incoming calls in queues and

distribute them to various operator consoles.

Incoming call

identification (which

should be able to identify

intra-group/out-group

incoming calls)

The interface of the operator console can distinguish and display

intra-group/out-group incoming calls.

Operator night service The operator console can forward incoming calls to a specified phone

before exit.

Operator

monitor/chime-in/forced

clear

Operators can monitor conversations of intra-group subscribers;

Operators can chime in conversations of intra-group subscribers by force;

Operators can clear a subscriber being in conversation by force and talk

to the other party of the conversation.

Operator console transfer The operator console can transfer intra-group or out-group calls while

generate CDRs at the same time.

Ring-back/re-ringing For subscribers just coming into conversation with operators, operators

can call them again via ring-back and re-ringing after hook-on.

Multi-group call

Telephone conference It is independent from the work handling function and integrates the

conference member edition and telephone conference control.


5-14


Alarm setting and call

status indication

Operators can set alarm time for intra-group subscribers and observe call

status of them.

Called number edition Operators can edit phone lists according to their respective habits.

Keypad and abbreviated

dialing

Operators can dial via keypads of PCs and use abbreviated numbers

defined by themselves.

Number retrieval Operators can query a certain number in phone number lists.

New service registration

for subscribers

Operator consoles can register or cancel new services in place of

intra-group subscribers.

Computer operator

(automatic operator

service)

Out-group subscribers can dial the indicating line to log in to computer

operator consoles, hear voice announcements and dial extension numbers

so as to realize automatic forwarding.

Bill processing statistics

of operator console

The operator console can generate CDRs containing the following

information: calling number, called number, conversation duration, date

and time, charging unit and charging area. In addition, it provides various

types of statistical processing.

Operator console

authority management

It provides such functions as adding/modifying an operator as well as the

operator login, log and work shift management.

5.2.3 IP Public Phone

ZTE softswitch control equipmentZXSS10 SS1a/1b can provide the IP public phone

service. As the charging mode varies, we can divide the IP public phone service into

two implementation types: compact and standard.

The compact IP public phone service uses the traditional meter in charging. The

corresponding user ports of IAD or AG are connected with the meter. When a

conversation ends, the softswitch control equipment will tell IAD or AG to generate a

polarity reversal pulse, which will provided for the connected meter for charging. This

mode needs no configuration of extra equipment at the network side. Being simple and

quick in implementation, it is applicable to self-employed business operators. However,

the compact IP public phone is only applicable to ordinary phones supporting IAD/AG

access and cannot be applied in intelligent terminals and visual terminals. In addition,

its charging algorithm management is difficult and the charging duration is incorrect.

Therefore, it is not recommended to apply this charging mode in large-scale IP phones.


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IP network

Softswitch

IAD

IAD

Chargingmeter

Cha rgingmet er

Cha rgingmet er

Fig. 5.2-2 Simplified IP Public Phone

Substantially, the standard IP public phone service belongs to the prepaid service of the

softswitch control equipment, whose subscribers are calling prepaid subscribers.

During operation, it is necessary to configure the corresponding equipment at the

network and subscriber sides. Its structure is shown in Fig. 5.2-3.

The network side or the public phone management center includes three parts: the

management server, database and management agent. Generally, the database and

management server share the same PC server (hardware) platform; while management

agents are ordinary PCs installed with management software.


5-16

IP network

Softswitch

M anagementserver

Public phonemanagement center

IAD

IAD

IP Phone

Videophone

Business hall

Managementagent

Business agent

Fig. 5.2-3 Standard IP Public Phone

At first, the management server can be taken as an AAA sever, which interacts with the

softswitch control equipment via the Radius interface. When subscribers use the IP

public phone service, their calls will be sent to the management server of the public

phone management center from the softswitch control equipment via the Radius

interface for authentication and accounting. In addition, such management functions as

realtime disconnection will be implemented on these calls according to the charge.

The management server also provides the data storage function. It can save the data

configuration information, charging configuration information and generated charging

information of the public phone bar; realize centralized management of operation

agents of various business halls; complete information distribution (such as realtime

CDR transmission) to various operation agents; and give responses to operations of

operation agents (e.g.: prepaid deposit setting and charging query statistics etc.).


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The management agent provides such centralized management functions as data

configuration, charging setting and operation statistics of public phone bars. More

specifically:

1. It supports login of super administrators;

2. It supports management and setting of various public phone bars and superior

equipment;

3. It supports statistics and query of operation information of all public phone bars

and provides reports for settlement;

4. It supports uniform setting of the charge rate and charging algorithm or setting

of different charge rates and algorithms for different public phone bars;

5. It provides realtime monitoring of operation of various public phone bars.

At the subscriber side, it is necessary to configure operation agents and the

corresponding terminals. The operation agents interact with the management server at

the center, which perform some Client management functions (e.g.: prepaid deposit

setting and instant charging etc.). On the other hand, they control IAD at business halls

via the standard SNMP interface and perform such functions as phone unlocking and

phone status display.

The standard IP public phone is applicable to terminals of any types, including ordinary

phones supporting IAD/AG access, intelligent terminals and visual terminals, thus

facilitating implementation of uniform management. Therefore, it can be applied

widely in business halls providing integrated telecom services.

One IP public phone management center of the basic configuration can management 64

IP public phone bars simultaneously.

5.3 Traditional Intelligent Service

ZTE softswitch control equipmentZXSS10 SS1a/1b can interwork with ZTE intelligent

network equipment ZXIN10 SCP to provide all traditional intelligent services, as

shown in Table 5.3-1:


5-18

Table 5.3-1 Traditional Intelligent Service


Credit card service It allows subscribers to make calls at any phone without paying cash. In

this case, the charge is recorded in the specified account.

Prepaid Charging

Service It is a credit card service with the calling number as the card number.

Telephone ad service

Generally, one manufacturer applies for an AD telephone number and

then plays ADs to phones calling this AD number. After dialing this AD

number and hearing ADs of this manufacturer, ordinary subscribers can

dial the phone number they want to according to the voice prompt. In

this case, the call is free of charge or the subscriber pays a part of the

charge while the remaining charge of the charge is borne by the

manufacturer.

Concentrated payment

service for called

subscribers

A service subscriber can provide a free phone number for callers. Then,

the charge of all calls to this service subscriber will be borne by the

service subscribers.

"Connected all" service

The "Connected all" service includes the caller authentication

single-stage dialing IP telephone service, dual-stage dialing IP

telephone service, direct single-stage dialing toll service, dual-stage

dialing toll telephone service and credit card network access service etc.

Number portability

service

It allows a subscriber to remain the phone number as it is when the

geographic location changes or the carrier providing telecom services

changes.

Universal personal

communication

In this case, a subscriber can use a sole personal telecommunication

number (PTN) to get access to any network and cross multiple networks

to originate or receive any types of calls.

Telephone payment

service

It refers to such commercial payment acts as paying the electricity

charge, water charge or call charge via the telephone.

Televoting It is the service of polling via telephone networks.

VPN service

It allows service subscribers to set up their own private networks via the

public network. These personal networks can have their respective

codes and override regions or countries.

Telephone securities Subscribers can conduct such operations as trading and querying

securities or modifying passwords via any dual tone telephone.

Receiving end network

access service

The receiving end network access service means that when a subscriber

of a telecom network (i.e.: a fixed phone subscriber) makes a toll to a

subscriber of another telecom network (e.g.: a mobile subscriber), the

current originating end network access is changed to receiving network

access.


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Number change

notification service

The number change notification service provides subscribers with

number change prompts.

Toll busy grooming

service

The tool busy grooming service means that: when there is a toll to a

local subscriber but this subscriber is in conversation is in conversation

with another local subscriber, a prompt voice is inserted into the

conversation, reminding the former subscriber that there is a toll. The

called subscriber can select to continue making (hearing) the call or to

receive the toll in precedence.

Telephone payment

service

The telephone payment service enables subscribers to perform call

charge query and payment via the telephone.

Banking card telephone

It allows subscribers to make calls at any phone without paying cash. In

this case, the charge is recorded in the specified account but the source

of the call charge is the banking card.

5.4 IP Value-added Service

ZTE softswitch control equipmentZXSS10 SS1a/1b can interwork with ZTE

application server ZXUP10 to provide the IP value-added service shown in Table 5.4-1:

Table 5.4-1 IP Value-added Service


Clicking dialing Subscribers can originate calls by clicking phone numbers on the WEB page.

WEB 800

It is a kind of WEB-based called payment service. In this case, calls are

originated from PCs while the information input and selection are via the WEB

page. Service subscribers manage their own information via the WEB page

while administrators manage service subscribers via the WEB page.

WEB conference

It is a WEB-based conference telephone service. The conference information is

displayed on the WEB page. The conference chairperson makes a reservation

for the conference via the WEB page and conduct realtime management on the

conference. There are two modes for conference members to participate in the

conference: convergence and divergence. In addition, conference requests are

submitted to the chairperson via the WEB page.

Accounting card It allows subscribers to make calls at any phone without paying cash. In this

case, the call charge is recorded in the specified account.

Uniform message

It means to digitalize the voice information, electronic information (e.g.:

e-mails) and text information (e.g.: fax) and save them in the same format. The

information can be sent with any one in the following tools: e-mail, fax, voice

mail, MS and telephone. After being transformed and transmitted, the


5-20


information will be saved in the central mailbox of the system uniformly.

While receivers can connect to the system server with any tool at any moment

and place convenient to them and acquire needed information.

Voice mailbox

Visitors can leave messages for system subscribers and the latter can hear these

messages. In addition, this service allows subscribers to manage their personal

bulletins and let any visitor to hear their voices. In addition, subscribers are

allowed to conduct personal setting, including setting the login password and

welcome words.

ZXUP10 includes two parts: PARLAY gateway and application server. Here, the

PARLAY gateway interacts with the softswitch control equipment via SIP and allocates

appropriate protocols to calls from the softswitch control equipment. It can also

directly control the media server, provide calls with various media resources needed in

the services and charge the relevant services. In addition, the PARLAY gateway can

provide the API interface for the application server (it can be the application server of a

third party).

The application server is responsible for the logic execution and management of

various value-added services and intelligent services. It interacts with the PARLAY

gateway via PARLAY/CORBA.

ZTE softswitch control equipmentZXSS10 SS1a/1b can also interact with the service

equipment of a third party via SIP to provide the IP value-added service of the third

party. The application server of the third party can use API provided by ZXUP10 for

service development. It can also interact with the PARLAY gateway directly via

PARLAY/CORBA and then interact with the softswitch control equipment via the

PARLAY gateway. Moreover, it can support independent service development and

interact with the softswitch control equipment directly via SIP, as shown in Fig. 5.1-1.

5.5 Multimedia Service

ZTE softswitch control equipmentZXSS10 SS1a/1b can directly provide the

point-to-point video service, i.e.: videophone.

ZXSS10 SS1a/1b can interwork with ZTE videoconferencing system to provide the

multimedia conference function.

6-1

6 Networking Mode and System Configuration

Summary

This chapter introduces the connection, networking mode and specific configuration of

the product to users in the form of solutions/examples so that users have an

understanding of the networking capability, service provisioning capability and

environment adaptation capability of the product.

6.1 Networking Mode

ZX SS10SS SS1a/1b softswitch control equipment supports various networking modes,

which is characteristic of sound expansibility, powerful system processing capability

and complete product series. It can provide multiple networking modes according to

deferent demands and network environment. Therefore, it can meet requirements for

not only large-scale networking in telecom operation but also networking of

medium/small enterprises or event residential communities.

In summary, the softswitch control equipment can provide two networking modes:

backbone network (Class 4) and local network (Class 5).

6.1.1 Networking Mode of Backbone Network

Application situation: the user has a toll backbone data network and local call network.

Equipment configuration: ZXSS10 SS1a/1b+ZXSS10 M100+ZXSS10 S100

The networking example is shown in Fig. 6.1-1. We can provide the toll telecom

service on the backbone data network for interworking with the PSTN and IN networks

and services. Here, the Softswitch equipment serves as the control equipment, which is

responsible for performing such functions as call control, resources allocation, charging

management and signaling protocol control. If SS7 is adopted in the PSTN network,

the trunk gateway (TG) will be responsible for the SS7 trunk access and the signalling

gateway will be responsible for the SS7 adaptation, converting circuit bearing to IP

bearing.


6-2

If the PRI signaling system is adopted in the PSTN network, MG (TG) will process the

voice media and signaling uniformly. In this case, SG can be omitted. Equipment

configuration: ZXSS10 SS1a/1b+ZXSS10 I704.

Backbone network

Signalling stream

Media stream

No.7Network

ZXSS10 S100 ZXSS10 M100

ZXSS10 1a/1b

LANSwitch

OSSClient

City 1

ZXSS10 S100ZXSS10 M100

Computer

Telephone

Telephone

PSTN/ISDN

No.7Network

Computer

Telephone

Telephone

PSTN/ISDN

City 2

MAN

Fig. 6.1-1 Class 4 Solution

6.1.2 Networking Mode of Local Network

Application situation: the user has a local data network, i.e., MAN.

Equipment configuration: ZXSS10 SS1a/1b+ZXSS10 M100+ZXSS10 S100+AG

or such access devices as IAD and the intelligent terminal.

As the network resources and environment vary, the following solutions can be

provided respectively: SoHo solution, community solution and intelligent terminal

solution, as shown in Table 6.1-1.

Table 6.1-1 Various Solutions

Solution Home/SOHO Desktop Corridor Community School Commercial

Building

SOHO solution

Community solution

Intelligent terminal

solution

Chapter 6 Networking Mode and System Configuration

��

6.1.2.1 SOHO Solution

The mode of ZXSS10 SS1a/1b+ZXSS10 M100+ZXSS10 S100+ZXSS10

I500/600 is adopted in this solution. The environment is that users only have Class 5

cable instead of twisted pair resources. It is mainly applied in homes/SOHO, corridors,

schools and commercial buildings. The advantages of this solution are: the mode is

simple, current network resources can be fully utilized and subscriber access is fast.

Users can select ZXSS10 I500 series or ZXSS10 I600 series so as to provide the pure

voice or voice/data-integrated service according to actual needs. Moreover, users can

select different types for use in residences, corridors or offices. In the networking

example shown in Fig. 6.1-2, the home voice/data-integrated solution provided by

ZXSS10 I601 is adopted. In addition, multi-port IAD600 series products can be used in

corridors or offices.

MAN

Computer

Telephone

ZXSS10 S100 ZXSS10 M100 Central equipment room

ZXSS10 1a/1b

LAN Switch

OSS Client

Telephone

Telephone

ZXSS10I601

Telephone

No.7 NetworkPSTN/ISDN

Signalling stream

Media stream

Computer

Fig. 6.1-2 Solution Integrating Home Data and Voice


6-4

To utilize the multi-port IAD500 product, a networking example for the pure voice

solution used at corridors or offices is provided, as shown in Fig. 6.1-3:

MAN

Computer

Telephone

ZXSS10 S100 ZXSS10 M100Central equipment room

ZXSS10 1a/1b

LAN Switch

OSS Client

Telephone


Signalling stream

Media stream

Corridor LAN switch

Computer

Computer

ZXSS10 I503

Fig. 6.1-3 Pure Voice Solution of the Office (corridor)

6.1.2.2 Community Solution

The mode of ZXSS10 SS1a/1b+ZXSS10 M100+ZXSS10 S100 is adopted in this

solution. It is mainly applied in communities, group corporations and commercial

buildings. The advantages of this solution lie in its low cost. Via MG, it can provide

access of several hundreds to several thousands of ordinary telephone subscribers. The

networking example is shown in Fig. 6.1-4. Here, M100 provides trunk and subscriber

access at the same time.


��

MAN

Computer

Telephone


ZXSS10 1a/1b

LAN Switch

OSS Client

Telephone


Signalling stream

Media stream

ZXSS10 M100 �AG)

ComputerComputer

Community

Fig. 6.1-4 Community Solution

6.1.2.3 Intelligent Terminal Solution

The mode of ZXSS10 SS1a/1b+ZXSS10 M100+ZXSS10 S100+IP phone set mode

is adopted in this solution. Its environment is that users only have Class 5 cables. It is

mainly oriented to users using resources directly. The advantages of this solution are

that the mode is simple and users can better value-added and intelligent services

provided by networks.

This is a brand-new access mode, which directly uses such intelligent terminals as IP

Phone, PC and IP Fax to provide local services. It is applicable to the situation in which

users have widely distributed Class 5 cable resources. This solution can be adopted in

advanced commercial buildings and houses. The networking example is shown in Fig.

6.1-5:


6-6

MAN

Computer

Telephone


ZXSS10 1a/1b

LAN Switch

OSS Client

Telephone


Signalling stream

Media stream

LAN Switch

1 2 3

4 5 6

7 8 9

* 8 #

Computer IP Fax

Fig. 6.1-5 Intelligent Terminal Solution

For the above local networking solutions, if the conversation is only between

Softswitch network subscribers, PSTN interworking is unnecessary. In this case, TG

and SG can be omitted.

6.2 System Configuration

ZXSS10 SS1a/1b softswitch control equipment is a carrier class product. In the respect

of hardware design, all major components of the equipment provide hot backup and all

boards support the hot-swapping function so as to meet the high reliability

requirements of the system.

In consideration of reliability of carrier-class equipment, the basic configuration

principles are: the 1:1 backup mechanism is adopted for major boards, power modules,

the system control card (SC), and network interface card (NIC); and the quantity of

system protocol processing card (SPC) depends on the network capacity, which is in

the 1+1 backup mode.


��

ZXSS10 SS1a is a kind of medium-capacity softswitch control equipment, which can

be configured with 2~3 SPCs. In consideration of requirements for load sharing and

redundancy backup, it is recommended that ZXSS10 SS1a process 200 thousand or 20

trunks.

ZXSS10 SS1a can be configured with 2 NICs.

The configuration examples are as follows:

Table 6.2-1 ZXSS10 SS1a Hardware Configuration List 1

ZXSS10 SS1a Hardware Configuration List

No. Name Code Unit Quantity Remarks

1 4U plug-in box Piece 1

2 19’’ server rack ZX209.01J-2 Piece 1 The 6U cabinet can be

selected too.

3 Backplate BSSA Piece 1

4 Network interface card NIC Piece 2~3

5 System control card SC Piece 2

6 System protocol processing

card SPC Piece 3

7 System switching network card SSN Piece 1

8 System switching network card

interface SSNI Piece 1

9 Transport interface card TIC Piece 1

9 System control interface card SCI Piece 2

10 Data maintenance management

server Piece 1 Sun Netra T1

11 Right power box SPWAR Piece 1

Mixed use of the right

and left powers is not

allowed.

12 Left power box SPWAL Piece 1

13 Feed box SPWAP Piece 1

14 Fan box SPWAF Piece 1


6-8

Table 6.2-2 ZXSS10 SS1b Hardware Configuration List 2

ZXSS10 SS1a Hardware Configuration List


1 4U plug-in box Piece 1

2 19’’ server rack ZX209.01J-2 Piece 1 The 6U cabinet can be

selected too.

3 Backplate BSSA2 Piece 1

4 Network interface card NIC Piece 2~3

5 System control card SSC Piece 2

6 System protocol

processing card SPC Piece 3

7 System switching network

card SSN Piece 1

8 System switching network

card interface SSNI Piece 1

9 Transport interface card TIC Piece 1

10 Data maintenance

management server Piece 1 Sun Netra T1

11 Right power box SPWAR Piece 1

Mixed use of the right

and left powers is not

allowed.

12 Left power box SPWAL Piece 1

13 Feed box SPWAP Piece 1

14 Fan box SPWAF Piece 1

Table 6.2-3 ZXSS10 SS1a Background Configuration List

ZXSS10 SS1a Background Configuration List No. Name Unit Quantity Remarks

1 PC Piece 1

1GHz master frequency/512MB memory/20GB hard

disk/10/100M network card×2/17 inch CRT,

Win2000 operating system pre-installed

ZXSS10 SS1b is a kind of large-capacity softswitch control equipment. According to

subscriber capacity, it can be configured with 3~13 SPCs, which provides the

processing capacity of 2 million subscribers or 200 thousand trunks at most.


��

The general configuration principles for SPC are: each card supports 170 thousand

subscribers or 17 thousand trunks. This is an appropriate calculation. In actual

engineering, the configuration quantity of SPCs should be ultimately determined

according to the actual traffic model and in consideration of such factors as network

security and load sharing.

The ZXSS10 SS1b softswitch control equipment can be configured with 2~6 NICs.

Since NIC supports the 1:1 backup mode, there are three configuration modes for the

card: 2 such cards, 4 such cards and 6 such cards. The configuration principles are:

1. According to capacity

In case of subscriber capacity<660 thousand or trunk capacity <66 thousand, 2

NICs should be configured;

In case of 660 thousand<subscriber capacity<1,320 thousand or 66

thousand<trunk capacity<132 thousand, 4 NICs should be configured;

In case of 1,320 thousand <subscriber capacity<2 million or 132 thousand<trunk

capacity <200 thousand, 6 NICs should be configured.

2. According to user requirements

For the service data traffic, 2 NICs are needed;

For communication between remote Softswitches, 2 NICs are needed;

For NMS traffic, 2 NICs are needed.

The configuration examples are as follows:


ZXSS10 SS1b Hardware Configuration List


1 12U plug-in box Piece 1 �

2 19’’ server rack ZX209.01J-2 Piece 1 �

3 Backplate BSSB Piece 1 �

4 Network interface card NIC Piece 2~6 To be configured in pairs

5 System control card SC Piece 2 �

6 System protocol processing card SPC Piece 3~13 �


6-10


7 System switching network card SSN Piece 2 �

8 System switching network card

interface SSNI Piece 1 �

9 Transport interface card TIC Piece 1 �

10 System control interface card SCI Piece 2 �

11 Data maintenance management

server � Piece 1

Sun Netra t1400/1405

/2*400MCPU/ 8M Cache/ 2G

memory/36G*4 hard disk/Dual

network cards/CDROM/AC200

12 Power box SPOWB Piece 2 �

13 Power distribution box SPOWP Piece 1

14 Fan box SPWBF Piece 1




1 12U plug-in box � Piece 1 �

2 19’’ server rack ZX209.01J-2 Piece 1 �

3 Backplate BSSB2 Piece 1 �

4 Network interface card NIC Piece 2~6 To be configured in pairs

5 System control card SSC Piece 2 �

6 System protocol

processing card SPC Piece 3~13 �

7 System switching

network card SSN Piece 2 �

8 System switching

network card interface SSNI Piece 1 �

9 Transport interface card TIC Piece 1 �

10 Data maintenance

management server � Piece 1

Sun Netra t1400/1405

/2*400MCPU/ 8M Cache/ 2G

memory/36G*4 hard

disk/Dual network

cards/CDROM/AC200

11 Power box SPOWB Piece 2 �


��


12 Power distribution box SPOWP Piece 1

13 Fan box SPWBF Piece 1

Table 6.2-6 ZXSS10 SS1b Background Configuration List

ZXSS10 SS1a Background Configuration List No. Name Unit Quantity Remarks

1 PC Piece 1

1GHz master frequency/512MB memory/20GB hard

disk/10/100M network card×2/17 inch CRT, Win2000

operating system pre-installed

A-1

AppendixA Analysis of Common Technical Indices

A.1 Delay Analysis

For such un-realtime services as data, the influence of jitter and delay should be taken

into full consideration when such realtime services as voice and video are provided on

the IP network so as to provide high quality services. According to ITU-T G.114

recommendations, when the unidirectional delay is more than 150ms, you may feel that

the conversation continuity is affected. The maximum tolerable delay is 400ms~500ms.

Only half duplex communication is available if the actual delay is beyond this value. If

echo is involved, the unidirectional delay is not allowed to exceed 25ms. Otherwise,

the echo suppression function is necessary.

In the normal network environment, the ZXSS10 SS1a/1b softswitch system can

provide high quality voice services. The detailed analysis and calculation method are as

follows:

The so-called delay is the time of message forwarding of the softswitch system. During

the process in which a voice packet reaches B from A via the IP network, there will be

corresponding time overhead at each link: transmitting, transmission and receiving.

Some overhead is fixed for the system while the other depends on the network

environment.

The time overhead generated during the voice signaling processing process is

composed of four parts: algorithm delay, calculation delay, assembly delay and

transmission delay, which belong to fixed overhead of the system. Their sum is called

unidirectional system delay. The algorithm delay fully depends on the algorithm, which

is irrelevant to specific implementation. For low rate codes, its typical value is 15ms.

The calculation delay refers to the encoder analysis time and decoder reconstruction

time. Its value depends on the hardware speed. Generally, it can be considered that the

calculation is equal to or a bit less than the frame length, so as to ensure that after the

next frame of data arrives completely, the current frame processing has ended. The

assembly delay refers to the multiplex delay. Before transmitting of the encoder and


A-2

decoding action of the decoder, it is necessary to assemble all bits of the entire data

block.

Strictly speaking, the transmission delay should include overhead generated from the

upstream/downstream links and backbone network transmission. The delay caused by

backbone network transmission is more affected by the network environment.

Therefore, when considering fixed overhead of the system, we generally refer to the

delay caused by the upstream/downstream links. For a shared channel, it is generally

supposed that the sum of the transmission delay and assembly delay is equal to the

length of a frame.

In appropriate estimation, the unidirectional system delay is at least 3 frames’ length,

which is fixed overhead of the system. In consideration that such network

environments as the network load and jitter buffer setting may distinctly affect the total

delay, the delay caused by end-to-end communication should generally be more than

the unidirectional system delay.

Now, let us take the G.729 coding algorithm with the best performance as example to

describe the delay allocation and calculation in end-to-end communication.

The G.729 algorithm delay is appropriately 15ms, its frame length is 10ms, and its

unidirectional codec delay is appropriately 25ms. In consideration that the backbone

network transmission is greatly affected by the network environment, we might as well

suppose that the total transmission delay is approximately 50ms. The buffer set at the

receiving end to remove packet jitter will directly affect the network delay. In

consideration of the balance between the delay and jitter, we might as well suppose that

the delay caused by the jitter buffer strategy is approximately 50ms. In this way, when

the G.729 algorithm is adopted, in consideration of such factors as the network

environment, the average delay of the system as a result of end-to-end communication

is approximately 25+50+50=125ms. According to ITU-T G.114 recommendations,

when the unidirectional delay is more than 150ms, it can be felt t hat the conversation

continuity is affected. The maximum tolerable delay can be 400ms~500ms. Therefore,

when the G.729 algorithm is adopted for the system, higher voice quality can be

guaranteed if the network is normal. For the 64kbit/s G.711 algorithm, since its

system delay is very low, even when the network is busy and the environment is

adverse, the conversation requirements can be ensured.


��

When the G.723.1 algorithm is adopted, its algorithm delay is 37.5ms and frame length

is 30ms. Since its system delay is higher, the performance is lower and its requirements

for the network environment is higher.

ZXSS10 SS1a/1b supports ITU-T G.711, G.723, and G.729 recommendations.

A.2 Traffic Analysis

A.2.1 Network Traffic Analysis

The network traffic of the ZXSS10 softswitch system generally includes contents of the

following aspects:

1. Voice traffic (such as RTP stream).

2. Signaling traffic, including H.248, MGCP, SIP, H.323, ISUP and TCAP etc.

3. CDR charging traffic.

4. NMS traffic etc.

In the following analysis process, for conveniences of the calculation, we take ZXSS10

SS1b carrying 2 million subscribers as example. In this case, BHCA is 2M and CAPS

is 602 appropriately.

1. Voice traffic

The voice traffic occupies the biggest proportion in the network traffic of the

softswitch system. We will take the G.711 algorithm that occupies most

bandwidth as example.

When the G.711 codec mode is adopted, the voice rate will be fixed at 64kbps.

In this case, the typical values of voice frame length in each IP packet will be

5ms (40B), 10ms (80B), 15ms (120B) and 20ms (160B); and the overheads of

RTP are: MAC frame (18B), IP (20B), UDP (8B) and RTP (12B) (58byte

altogether). In addition, the RTCP data stream occupies about 5% of the load

bandwidth. Therefore, the calculation of the unidirectional voice bandwidths is

as follows:

602 % (1000/5) % (40+58) (1+5%)% 8=99113280bps=99.1Mbps

602 % (1000/10) % (80+58) (1+5%)% 8 =69783840bps=69.8Mbps

602 % (1000/15) % (120+58) % (1+5%)% 8=60007355bps=60.0Mbps


A-4

602 % (1000/20) % (160+58) (1+5%)% 8=55119120bps=55.1Mbps

2. Signaling traffic

In various call situations, the call between two IAD subscribers via the H.248

protocol occupies the most network bandwidth. When the protocol is in the

standard text format (bytes needed in this mode are the highest), the signaling

traffic for a call will be 63.36kb/s approximately. We will take this as a model to

calculate the signaling traffic needed in a single frame of ZXSS10 SS1b under

full configuration.

The calculation basis is that the processing capability is 2 million subscribers

and the calls of all subscribers are via H.248 (worst case).

When the CPU occupation ratio of the system is 55%, the processed calls per

second (CAPS) for a single-frame system under full configuration is:

46.3%13≈602

And the required signaling traffic is:

602%63.36=38136.38Kbps≈38Mbps

3. CDR traffic

No matter whether the call is successful, ZXSS10 SS1a/1b will generate CDR

files for calls it receives. Generally, the transmission of each CDR will cause a

bandwidth consumption of 559 bytes.

The bandwidth required for CDR transmission is:

602%559=336518Bps≈2.7Mbps

4. NMS traffic

The NMS works in the centralized management mode, i.e.: NMS performs

multi-NE oriented management, collects performance data and receives such

information as alarms. Therefore, the bandwidth bottleneck lies in the network

bandwidth allocation at the NMS side. In addition, there is no direct

correspondence between the NMS traffic and network traffic. However, it is

directly related to the polling frequency and alarm density. Therefore, when

analyzing the NMS traffic, we need to take the processing capability of ZXSS10

NMS as example in calculation.


��

The packet processing capability indices of ZXSS10 NMS are as follows:

1) The processing capability of trap packets reaches 100 pieces/s.

2) The Mib variable retrieval capability is 100 pieces/s (polling).

Therefore, in extreme situations, i.e. when the system reaches the above

processing requirements (dense alarms, simultaneous polling) at the same

moment, the calculation of required bandwidth is as follows:

1) If the average length of each trap packet is 300byte, we can get:

100×300=30000 (byte/s)=234kbps.

2) The polling is in the bi-directional (request/response) access mode. If the

average length of each polling (MIB variable) data packet is 250byte, we can get:

100×250×2=50000 (byte/s)=390kbps.

Therefore, in extreme cases, the bandwidth at the NMS side is required to be:

234+390=624kbps.

When the system is running normally, the probability of dense alarms and large

batches of data polling is lower. Therefore, generally, a 40%~60% weight is

multiplied and the bandwidth at the NMS side is required to be 250k

bps~380kbps. For the bandwidth requirement at the managed NE side, the

average algorithm is generally adopted, which is L/N. here, L indicates the

bandwidth at the NMS side; while N indicates the number of managed NEs.

Compared with the voice traffic and signaling traffic, the NMS traffic can be

ignored.

In summary, when the software switching system carries 2 million subscribers,

the total bandwidth needed in extreme cases is only at 100M. In consideration of

the fast bandwidth increase of the current data network, the backbone network,

MAN and subscriber desktop can provide the gigabit, 100M and 10M bandwidth

respectively, which can fully meet the bandwidth requirements of the softswitch

network in providing integrated services.

A.2.2 Traffic Analysis of Softswitch Control Equipment

For the softswitch control equipment, the traffic includes signaling traffic, CDR

charging traffic and NMS traffic. According to the above analysis, we can determine


A-6

that when SS1b carries 2 million subscribers, the maximum signaling traffic is 35Mbps

and the maximum CDR traffic is 2.5Mbps.

The NMS traffic at the side of the softswitch control equipment that is less than

380kbps can be ignored.

Obviously, for the bandwidth, only several dozens of megabits are needed when the

softswitch control equipment processes 2 million subscribers. Therefore, a 100M

Ethernet interface can fully meet the bandwidth requirements.

B-1

AppendixB ZXSS10 SS1a/1b Protocol Stack

The ZXSS10 SS1a/1b softswitch control equipment is a protocol entity. The system

supports interworking among various networks relying on various protocols. This

implementation mode ensures sound adaptability of the system to future technologies.

Once a new technology emerges, it is only necessary to upgrade the software version

and provide the corresponding interface at the gateway equipment of the edge layer

without large-scale renovation of the hardware.

As a whole, ZXSS10 SS1a/1b supports YDC 003-2001 Overall Technical

Requirements for Softswitch Equipment of MII. The specific protocols involved include:

MGCP, MEGACO/H.248 protocol, SIP, ISUP/TUP, SNMP, M3UA protocol, SCTP,

H.323 protocol, SCCP, TCAP, INAP, PRA signaling protocol and R2 signaling protocol

etc.

B.1 Megaco/H248 Protocol

The Megaco/H.248 protocol is used between the softswitch control equipment and

various gateway gateways. In this protocol, two abstract conceptions are defined:

Termination and Context.

A termination sends and/or receives one or more data streams. In a multimedia

conference, one termination can support multiple media and send or receive multiple

media streams. At the termination, the media stream, modem and bearing capability

parameters are encapsulated.

The context indicates the connection relationship between some terminations. There is

special context, i.e. null context, which refers to the collection of all terminations that

has no contact with any other terminations. For example: in a divided access gateway,

all idle circuits can be represented with a termination in the null context.

In H.248, eight commands are defined, which are Add, Modify, Subtract, Move,

AuditValue, AuditCapability, Notify and ServiceChange respectively.

A group of commands between the media gateway and softswitch control equipment

compose a transaction interaction. One transaction interaction can be identified with a


B-2

TansactionID. It is composed of one or more actions. An action is composed of a series

of commands used in a context. Therefore, an action can be identified with a ContextID.

Fig. B.1-1 is a schematic diagram showing the relationship between transactions,

actions and commands.

Command 1

Transaction

Command 3 Command 4

Command 2Context1

Command 1

Command 1

Command 3

Command 2Context3

Context2

Fig. B.1-1 Relationship between Transactions, Contexts and Commands

Transaction interactions ensure command processing in order. That is to say,

commands in a transaction interaction is sequentially executed. However, orderly

processing between different transaction interactions is not ensured, i.e., transaction

interactions can be processed in any sequence or simultaneously.

If the execution of a command fails during a transaction interaction process, the

execution of all the other commands in this transaction will be stopped.

For each transaction, an application layer timer should be set. If the timer expires, the

request information will be retransmitted. If a reply is received, the timer will be

cancelled. If "Pending" is received, the timer will be restarted.

B.2 MGCP Protocol

MGCP is a protocol used between the softswitch control equipment and MGCP

terminal. The MGCP connection model is based on two components: endpoint and

connection. The endpoint sends or receives data streams, which can be either physical


��

or virtual. The terminal controlled by the softswitch control equipment is responsible

for setting up connections between call-related endpoints, which can be either

point-to-point or point-to-multipoint connections. Connections are divided according to

different calls. Multiple connections can be set up at one endpoint and connections of

different calls can be terminated at one endpoint.

The MGCP command includes types of commands: connection processing commands

and endpoint processing commands. There are altogether 9 commands, which are

EndpointConfiguration, NotificationRequest, Notify, CreateConnection,

ModifyConnection, DeleteConnecation, AuditEndpoint and RestartInProgress

respectively.

All MGCP commands need acknowledgement of the receiver. The acknowledgement

message contains Return Code, which indicates the command execution status and is

an integer.

Reason Codes

"Reason Codes" can be used in the DeleteConnection command originated from the

terminal to notify the softswitch control equipment of the reason for connection

deletion. It can also be used in the RestartInProgress command to notify the

softswitch control equipment of the reason for restart. Reason code is an integer.

B.3 SCTP Protocol

The major purpose of SCTP used in stream transmission is to transmit the PSTN

signaling message over the connectionless network. This protocol can be used in the IP

network to provide the reliable data transmission protocol. More specifically, SCTP is

used to transmit subscriber data without any error and repeat in the acknowledgement

mode. It provides subscriber data segmentation according to MTU restriction at the

channel and ensures sequential submission of subscriber messages over multiple

streams. It can multiplex messages of multiple subscribers to the SCTP data block and

use the SCTP coupling mechanism to provide network-level fault guarantee. Moreover,

SCTP can avoid congestion as well as broadcast and anonymous attacks.

At present, SCTP runs in the IP network in most cases. SCTP can provide the reliable

message transmission service between two SCTP subscribers. This service is made

possible via coupling between two SCTP termination points.


B-4

B.4 M3UA Protocol

M3UA is an MTP3 adaptation protocol. M3UA uses SCTP as the reliable lower-layer

signaling transmission protocol. Fig. B.4-1 shows the applied protocol stack in M3UA.

SEP/STP SG ASP

MTP3

MTP2

L1

ISUP etc.

M3UA

SCTP

IP

MTP3

MTP2

L1

M3UA

SCTP

IP

(NIF)ISUP etc.

Fig. B.4-1 M3UA Application

In SG, the MTP-TRANSFER indication primitive received from the MTP3 upper layer

interface is transmitted to the local M3UA to translate and map the network address

and then routed to the final IP destination. The MTP-TRANSFER primitive received

by the function of local M3UA network address translation and mapping serves as the

MTP-TRANSFER Request primitive, and is transmitted to the MTP3 upper layer

interface, and further routed to SEP in SCN.

M3UA provides the following services:

1. Support the transmission of MTP3 user message

M3UA sends an MTP-TRANSFER primitive via SCTP coupling, which is then

coded to the MTP3 message with the MTP3 routing flag.

2. Local management function

M3UA provides the management over lower SCTP transmission protocol,

ensuring that SG-ASP transmission is available for MTP3 user signaling

application.

M3UA provides the capability of relevant error indication for the received

M3UA message and appropriate notification to the local management and/or

remote M3UA.


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3. Interconnection with the MTP3 NM function

M3UA should provide interworking with the MTP3 NM function, so as to

ensure that the following operations can be conducted in the No.7 and IP

domains on subscriber signaling messages:

1) Provide ASP MTP3 subscribers with the indication of remote destination in the

No.7 network unreachable.

2) Provide ASP MTP3 subscribers with the indication of remote destination in the

No.7 network reachable.

3) Provide ASP MTP3 subscribers with indication when message transmission at

the remote peer MTP3 subscriber layer in the No.7 network is congested.

4) Provide ASP MTP3 subscribers with the indication of "Remote peer MTP3

subscribers in the No.7 network unavailable".

4. Support for management of SCTP coupling between the far end and ASP

The remote M3UA layer maintains the availability status of all configured

remote ASPs. Similarly, to manage the SCTP coupling and service between the

far end and ASP, the activated/inactivated status of ASP is maintained by the far

end too. Activated ASPs are those receiving services from the far end.

In the local management, the remote or ASP M3UA layer can be ordered to set

up the SCTP coupling to the peer M3UA node. They can use the M-SCTP

ESTABLISH request, indication and acknowledgement primitive to set up the

SCTP coupling to the peer M3UA node.

The M3UA layer can also use the M-SCTP STATUS request and indication

primitive to notify the local management layer of the status of the lower-layer

SCTP coupling. For example: M3UA can notify the local management of the

cause leading to SCTP coupling release, thus determining whether it is released

by the local M3UA layer or SCTP.

In addition, the M3UA layer can notify the local management of changes to the

ASP availability status, which can change and indicate the ASP status by using

the M-ASP STATUS primitive.


B-6

B.5 SIP Protocol

The softswitch control equipment interworks with the SIP system via SIP (session

initiation protocol, IETF RFC2543). SIP is a kind of application layer control protocol

put forward by IETF for multimedia communication over the IP network, which can be

used to set up, modify and terminate multimedia sessions and calls. SIP is independent

from the lower layer protocol TCP or UDP, which ensures reliable message

transmission via its application layer. In addition, the Client-Server mode based on the

text format is adopted in SIP, which indicates the message syntax, semantics and code

in the text form. In this case, the Client originates requests and the Server gives

responses.

A typical SIP session/call setup process is shown in Fig. B.5-1:

UAC PROXY

1. INVITE

4. Response

6. ACK 5. ACK

3. Response

2. INVITE

UAS

Fig. B.5-1 Typical SIP Session/Call Setup Process

SIP is a Client/Server protocol. The are two types of protocol messages: request and

response. The request message is sent from the Client to the Sever; while the

response message is sent from the Server to the Client. Its purpose is to set up or

terminate sessions, which can be the Internet multimedia session, Internet telephone

call or multimedia information stream allocation.

An SIP call is identified with a globally unique Call-ID. SIP mainly supports functions

in the following five respects:

1. Subscriber location: determine the end system location used in the

communication.

2. Subscriber capability switching: determine the used media type and media

parameters.


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3. Subscriber availability judgment: determine whether the called party is idle and

willing to join the communication.

4. Call setup: invite and remind the called party and transmit call parameters

between the calling and calling parties.

5. Call processing: include call termination and call transfer etc.

B.6 No.7 UP Protocol

For the subscriber part of the No.7 system, please refer to relevant recommendations of

ITU-T and China MII.

��C-1

AppendixC Abbreviations

Abbreviation Full Name

AAA Authentication, Authorization, Accounting

AG Access Gateway

AH Authentication head

API Application Program Interface

ARP Address Resolution Protocol

AS Application Server

ASIC Application Specific Integrated Circuit

ASP Application Server Process

ATM Asynchronous Transfer Mode

AU Adaptation Unit

AU Access Unit

BHCA Busy Hour Call Attempts

BICC Bearer Independent Call Control

BUSI Bus Interface

CCITT International Consultative Committee For Telephone and Telegraph

CDR Call Detail Record

CIC Circuit Identification Code

CLI Command Line Interface

C0MM Communication board

COPS Common Open Policy Service

DDN Digital Data Network

DPC Destination Point Code

DT Digital Trunk

DTMF Dual Tone Multi-Frequency

DWDM Dense WDM

FR Frame Relay

GK Gatekeeper

GTT Global Table Translation

GUI Graphic User Interface


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GW GateWay

H.248 ITU-T Rec. H.248 Gateway Control Protocol

H.323 ITU-T Rec. Packet-based Multimedia Communications Systems

HDLC High-level Data Link Control

HW High Wag

IAD Integrated Access Device

IAM IP Access Module

ICMP Internet Control Message Protocol

IETF Internet Engineering Task Force

IGMP Internet Group Management Protocol

IN Intelligent

INAP Intelligent Network Application Procedure

IP Internet Protocol

ISDN Integrated Service Digital Line

I/O Input/ Output

ISUP ISDN User Part ISDN

ITU-T International Telecom Union-Telecommunication standardization

M2PA MTP2-User Peer-to-Peer Adaptation Layer Protocol

M3UA MTP3 User Adaptor

MFC Multi-Frequency Control

MG Media Gateway

MGC Media Gateway Controller

MGCP Media Gateway Control Protocol

MONI MONitoring

MOS Mean Opinion Score,

MP Module Processor

MPMP Module Processor to Module Processor

MPPP Main Processor to Peripheral Processor

MSAG Media Service Access Gateway

MTP Massage Transfer Protocol

MTU Maximum Transmission Unit

MTUP MTP Test User Part MTP

AppendixC Abbreviations

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NAS Network Access Server

NGN Next Generation Network

NIC Network Interface Card

OAM Operation, Administration & Maintenance

OAN Optical Access Network

OMM Operation Maintenance Module

OPC Originating point code

OSS Operation Support System

PCM Pulse Code Modulation

PEPD Peripheral Environment Parameter Detection

PPP Point-To-Point protocol

PRA Primary Rate Access

PRI Primary Rate Interface

PSM Peripheral switching Module

PSTN Public Switch Telephone Network

QoS Quality of Service

RADIUS Remote Authentication Dial-In User Service

RARP Reverse Address Resolution Protocol

RTCP Realtime TraSPort Control Protocol

RTP Realtime Transport Protocol

SCN Switched Circuit Network

SC System Control (Card)

SCI System Control Interface

SCP Service Control Point

SCTP Stream control transmission protocol

SCCP Signalling Connection Control Part

SG Signal Gateway

SIGTRAN Signaling Transport

SIP Session Initiated Protocol

SIP-T SIP for Telephones

SEP Signaling end point

SNMP Simple Network Management protocol


C-4


SOHO Small office home office

SPC System Protocol Control (Card)

STB Signal Terminal Board

STP Signaling Transfer Point

SS SOFTSWITCH

SS7 Signalling System No. 7

SSC Softswitch System Control (Card)

SSN System Switching Network (Card)

SSNI System Switching Network Interface (Card)

SSP Service Switch Point

STP Signalling Transfer Point

SUA SCCP-User Adaptation Layer Protocol

TCAP Tc Application Part

TCP/IP Transmission Control Protocol/Internet Protocol

TDM Time Division Multiplexing

TG Trunk Gateway

TIC Transport Interface Card

TUP Telephone User Part

UDP User Datagram Protocol

VOIP Voice Over IP

WAG Wireless Access Gateway

WAN Wide Area Network

1b (V2.0) Softswitch Control Equipment Technical Manual

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