CCS7 (COMMON CHANNEL SIGNALING NUMBER 7) AS AN EXAMPLE OF THE ISDN

SIGNALING APPLICATION

By:

Baskoro Adiguna (0810630037)

Michella yessica (0810633062)

Rifa Kunantoro (0810633077)

signaling

There are two important components in a communication by telephone. The first and most important is the content of the communication itself, its voice, fax, data and so on. The second is information that ordered the telephone exchange to build a relationship of communication and direction to achieve desired goals. This information is referred to as signaling.

Signaling Aplication in ISDN

ISDN (Integrated service digital network) is the development of IDN which provides end-to-end digital network from one consument to other consument . in ISDN there are signaling systems call CCS7. CCS7 is one example of the application signaling.

CCS7

Signaling System No. 7 (SS7) signaling protocol is used to make calls most of the people in the world. Its main purpose is to call dialing and call dropping.including recognizing numbers, billing, short message service (SMS), and various other mass-market service. This is usually referred to as Signaling System Number 7 or Signaling System # 7, or simply abbreviated as SS7. In North America are often referred to as CCSS7, an acronym for Common Channel Signaling System 7. In some European countries, especially Great Britain, sometimes called C7 (CCITT number 7) and also known as number 7 and CCIS7.

Telecommunication networks examined by CCS 7 is formed by a number of nodes connected with each other in signaling links. These points are in the CCS7 network is called Signaling Points (SP). Broadly speaking, the SP can be divided into three types, namely:

1. Signaling End Point (SEP)SEP or commonly called the SP alone, is the source (originating point) and destination (destination point) of signaling.

2 Signalling Transfer Point (STP)STP is a signaling point that can transfer

messages from one channel signaling to other signaling channel.

3. Service Control Point (SCP)The function of SCP is to provide an interface to a computer database. This database is used to store information on service calls, routing to a special number (such as a freephone service 800), and provide services Intelligent Network (IN).

The relationship between SEP, STP, and SCP are shown in figure below:

CCS7 architecture

CCS7 consists of four levels, three levels of MTP [Message Transfer Part] and a Call Control Protocol or also called user parts. Here is a picture of a CCS7 structure:

Structure of CCS7 consists of functional blocks as follows:

1. MTP (message transfer part)The function of MTP in general is to guarantee the

transfer of signaling information through signaling networks and has the ability to perform the necessary action in response if there is damage in the system or network so that the transfer process is maintained from mistakes.

In the architecture above, it appears there are four levels, and each of these levels have different functions:

1. MTP level 1 (Signaling Data Link Part)In the MTP level 1 there is shown a block channel transmission and switching functions, which function is to define the character of the functional, physical and electrical signaling data link and the means to access them.

2. MTP level 2 (Link Signaling Function)

Security function on the second Layer MTP is intended for signaling units that are sent and received securely and accurately. Because every message sent is equipped with a flag of identity that allows to sort the message the message to each other. Each sub-section of a message signaling unit has a certain length. While the part that varies is usually a multiple of 8. To know the complete absence of received messages are used for message

sequence number of messages sent and received. Any messages sent from a higher layer has a Forward Sequence Number (FSN), which is the identity. The number has a value between 0 and 127. While the message is received by the SP, the recipient must provide information to the sender that this information has been received and the information necessary for this purpose benar.Untuk Backward Sequence Number (BSN). BSN contains information on FSN last value received without disabilities.

3. MTP level 3 (Signalling Network Function)

In the MTP level 3 load sharing process occurs between the signal link, is responsible for load sharing between link sets of signals on the route, MTP message routing and distribution to the users and applications to further proceed to the SCCP at the MTP level 4

2. User part

consists of functional blocks as follows:

A. SCCP (Signaling Connection Control Part)The task of routing fiber SCCP is Doing coding and decoding.Signaling Connection Control Part (SCCP) is a software

functional block on MTP.Together with the MTP, SCCP form the Network Service Part (NSP). Data transfer is done in the form of blocks of data called Network Service Data Unit (NSDU). MTP provides a flexible mechanism for data transfer and in accordance with the change of data between switching

nodes.

B. Closed (telephone user part)Using existing functionality on MTP to support the

telephone network

c. ISUP (ISDN user part)Provides functions to support the ISDN network and also has facilities to support the network telepon.User part (UP) is located the highest layer of the structure CCS7 signaling levels. consumption is a central part of the

user who wants tertentu.ISUP processes provide Signalling functions required to support basic bearer services and supplementary services for voice applications and non-voice on ISDN.

d. TCAP (transaction Application Capability Port)To support the GSM system

e. MAP (Mobile Application Part)Used in GSM and provide mobility management.

f. BSSAP (BSS Application Part)

Advantages and disadvantages of CCS7

A. Advantages• Message based

• Use out of band signaling is signaling method whereby the control signal is transmitted through the same path with the signal information, but occupy a different frequency, so that if one is damaged will have no effect on the other

• Can be reliable because it is able to handle high traffic

• Having greater flexibility in accepting new services applications with the availability of the possibility of defining a signal that quite a lot.

• Availability of high speed signal transmission (64 Kbit / s) will shorten the post-dialing delay. Average transmission time of a signal between the two central CCS7 is 70 ms, while for MFC-R2 system is 250 ms.

• Bearer does not have to keep the database fully each of the switching nodes, but can perform a remote database and search for information as soon as possible.

• SS7 is a merger of various storage systems to the network control program. This can speed up and streamline the call to the network settings in 1 second.

• Integration of the providers for supervision, monitoring, billing system integration for the better.

• Additional advantages SS6 SS7 is a network that has been replaced over 30 years, needs to upgrade the basic rights that are common to technological change and demand a fast, better service.

• Ability to transfer information in the correct order without any error / loss or duplication

B. Disatvantage• It can be difficult to apply

• Service dependent: if it will add new services or firtur, then we will need a new place in the signaling messages and it does require a software upgrade.

• Initial investment costs are relatively higher for the procurement of new devices, both for data transmission devices and for device control.

• Needed a more reliable security requirements for signaling data link

• CCS7 network is very complex concept that needs to be made nationally CCS7 network planning.

ENDThank you very much for your attention (^_^)