TDMoIP PT4 Intro Cust 020304

PacketTrunk-4TXC-05870

TDMoIP / MPLS Gateway Device

Feb. 03, 2004

TranSwitch Corporation Proprietary & Confidential 2

Contents

• TDMoIP: Introduction• PacketTrunk-4 Functionality• Clock Recovery & Measurement• PacketTrunk-4 Demo


1. TDMoIP: Introduction


Pseudowires

Pseudowire (PW): Pseudowire (PW): A mechanism that emulates the A mechanism that emulates the essential attributes of a native service while transporting essential attributes of a native service while transporting over a packet switched network (PSN)over a packet switched network (PSN)


Tunneling - interworking

Mating different network protocols is called interworking

The protocol converter goes by various names :– interworking function (IWF)– gateway (GW)

Simplest case is network interworkingEasily provided by tunneling

networkNativeService

NativeService


Emulating TDM

From PSTN to PSN


Classic Telephony

• Circuit switched ensures signal integrity

• Very High Reliability (“five nines”)

• Low Delay and no noticeable echo

• Timing information transported over the network

• Mature Signaling Protocols (over 3000 features)

T1/E1

COSWITCH

analog lines

SONET/SDHNETWORK

PBX

extensions

Access Network

T1/E1

PBX

Core (Backbone) Network

SynchronousNon-packet network

COSWITCH


TDMoPSN

The TDMoIP approach replaces the Network with a packet (IP or MPLS) networkThe access networks and their protocols remain !TDM PseudowireCan G.xxx compliance be maintained?

T1/E1/T3/E3

analog lines

PBX

extensions

Access Network

PBX

T1/E1

Packet Switched Network

Asynchronous networkNo timing information transfer


A few G.XXX sayings …

• G.114 (One-way transmission time)– delay < 150 ms acceptable– 150 ms < delay < 400 ms conditionally acceptable– delay > 400 ms unacceptable– G.126/G.131 echo control may be needed

• G.823/G.824 (timing)– Primary vs. secondary clocks– jitter masks– wander masks

• G.826 (error performance)– BER better than 2 * 10-4


TDMoIP vs. VoIP

Two ways to integrate TDM services into PSNs

VoIPVoice centric!• Revolution - complete (forklift) CPE replacement • New signaling protocols (translation needed)• New functionality (e.g. video-phone, presence)

TDMoIPClear channel/ leased line service• Evolution - CPE unchanged, IWF added at edge• No change to signaling protocols (network IW)• No new functionality• Migration path


TDMoIP as a Migration Path

• VoIP has promising future– but today’s installed base is still legacy TDM

• PSTN is not going to be replaced overnight

• Voice quality concerns (delay, compression, packet loss)

• TDMoIP can use new infrastructure with legacy CPE

• Maintains functionality of all PBX and Centrex features


TDMoIP Protocol Processing

Steps in TDMoIP

• The synchronous bit stream is segmented

• The TDM segments are adapted

• TDMoIP control word is prepended

• PSN (IP/MPLS) headers are prepended

• Packets are transported over PSN to destination

• PSN headers are utilized and stripped

• Control word is checked, utilized and stripped

• TDM stream is reconstituted and played out

TDMframes

TDMframes

IP Packets

PSN

IP Packets


TDMoIP Protocol Processing

Traffic Types:

• Structured (framed)

• Unstructured (unframed)

TDMframes

TDMframes

IP Packets

PSN

IP Packets


TDMoIP encap formats- For Structured Traffic(TDMoIP: IETF draft-Anavi-tdmoip-06)

encapsulation (encap) : process of adding protocol control information to data in order to build a packet for transport across an PSN


Functionality

What needs to be transported from end to end?• Voice (telephony quality, low delay, echo-less)• Tones (for dialing, PIN, etc.)• Fax and modem transmissions• Signaling (there are 1000s of PSTN features!)

– CCS (comon Channel Signaling), CAS (Channel Associated Signaling)

• Timing

T1/E1frame

SYNC TS1 TS2 TS3CAS

signalingbits

… … TSn

(1 byte)

“timeslots”


Why isn’t it easy

Why don’t we simply encapsulate the T1/E1 frame?

IP T1/E1 frame

24 or 32 bytes

UDP RTP?

Because a single lost packet would cause service interruption CAS signaling uses a superframe (16/24 frames) Superframe integrity must be respected

Because we want to efficiently handle fractional T1/E1

Because we want a latency vs. efficiency trade-off


The basic idea

Those problems can be solved by:• adding a packet sequence number• adding a pointer to the next superframe boundary• only sending timeslots in use• allowing multiple TDM frames per packet

Good idea! This is precisely AAL1 !

for example

UDP/IP T1/E1 frames (only timeslots in use)seqnum(with CRC)

ptr

TS1 TS2 TS5 TS7 TS1 TS2 TS5 TS77 @


why AAL1 – For Static Structured Traffic

“AAL1” is the simplest method to transport structured TDM traffic (voice, sync, signaling)

ATM community has done the debugging for us!

Any alternative will either• fall apart upon packet loss or

• be less efficient or

• mandate high latency (e.g. multiframe per packet) or

• be essentially equivalent (I.e. contain a structure pointer)


Isn’t that enough?

AAL1 is inefficient if the timeslots are not always in use

Although we can configure which timeslots are usedwe can not change this configuration in real-time!

To allow dynamic allocation of timeslotswe can use AAL2

AAL2 buffers each timeslot and encapsulates in a “minicell”

Bandwidth conservation comes at a price– more computation– less robust


AAL2 for Dynamic BW Traffic

AAL1 is BW inefficient when timeslots are dynamicEven with GB rates we should consider efficiency considerations

“AAL2” is the simplest method to transport dynamic structured TDM

Any alternative will either• fall apart upon packet loss or• be less efficient (e.g. require renegotiation) or• be essentially equivalent


Isn’t this just ATM?

AAL1 and AAL2 are adaptation protocolsoriginally designed to massage data into a format that can be readily used

As we have shown, they are natural candidates forany application which needs to multiplex timeslots

For TDMoIP we do not put the AAL1/2 into ATM cells (no 5 byte header)

Rather we put the AAL1/2 directly into a UDP/IP or MPLS packet

So, NO, this is NOT ATM

But it can easily interwork with ATM access networks!


Service Inter-working

TDMoIP is not the first TDM emulation technologyWe should also provide service interworking, existing ATM circuit emulation services (AAL1, AAL2)

PSN

E1/T1E3/T3

E1/T1E3/T3 TDMoMPLS GW

ATM-MPLS IWF

ATM/AAL1

ATM-CES GW

ATM layer

AAL1 AAL2 AAL5

CBR VBR n-rt


One More Payload type: HDLC

• Efficiently transfer CCS traffic (such as SS7 embeded in TDM traffic)

Assume messages shorter than the MTU (no fragmentation)– monitor flags until frame detected– test FCS– if incorrect - discarded– if correct -

• perform unstuffing• flags and FCS removed• send frame


TDMoIP layering structure – Structured Traffic

AAL1 used for static (and transparent) allocation: NxAAL1 (N=1..31)

AAL2 used for dynamic bandwidth: NxAAL2 (N=1..31)

HDLC used for CCS signaling and data (e.g frame relay)

PSN / multiplexing

Optional RTP header

TDMoIP Encapsulation

AAL1 AAL2 HDLC

higher layers


TDMoIP Control Word

For Structured Traffic:FORMID (4 b)

– indicates TDMoIP mode (AAL1, AAL1 - CAS, AAL2, HDLC)– ensures differentiation between IP and MPLS PSNs

Flags (2 b)– L bit (Local failure)– R bit (Remote failure)

Res (4 b):

Length (6 b) used when packet may be padded

Sequence Number (16 b) used to detect packet loss / miss-ordering

For UnStructured Traffic:FORMID (4 b): 0000

Res:

FORMID flags Res Length Sequence Number


TDMoIP encap formats- For UnStructured Traffic(SATOP: Draft-ietf-pwe3-satop)

SATOP: Structue-agnostic TDM over Packet)


Payload Type of UnStructured Traffic

• TDM traffic is treated as RAW data

• TDM bit stream is put into payload field

• The payload size is defined during setup

• Payload size remains the same

• It should support the payload size:– T1: 192 bytes– E1: 256 bytes– T3 and E3: 1024 bytes

• If RTP is used:– Clock used for time stamp must be an integer of multiple 8Kz


TDMoIP encap formatsSummary


TDMoIP layering structure

PSN / multiplexing

Optional RTP header

TDMoIP Encapsulation

TDM Over IP Payload

higher layers


TDMoIP Control Word

For Structured Traffic:FORMID (4 b)

– indicates TDMoIP mode (AAL1 w/o CAS, AAL1 w/CAS, AAL2, HDLC)– ensures differentiation between IP and MPLS PSNs

Flags (2 b)– L bit (Local failure)– R bit (Remote failure)

Res (4 b):

Length (6 b) used when packet may be padded

Sequence Number (16 b) used to detect packet loss / miss-ordering

For UnStructured Traffic:FORMID (4 b): 0000

Res:

FORMID flags Res Length Sequence Number


TDMoIP packet format

IP header (5*4bytes)

UDP header * (2*4bytes)

Optional RTP header (3*4bytes)

TDMoIP header (4bytes)

TDMoIP payload

* The UDP source port number is used as a bundle identifierNotes


IPVER IHL IP TOS Total Length

Identification Flags Fragment Offset

Time to Live Protocol IP Header Checksum

Source IP address

Destination IP address

VER Circuit Bundle Number Destination Port Number

UDP Length UDP Checksum

RTV P X CC M PT RTP Sequence Number

Timestamp

SSRC Identifier

FORMID L R Z Length Sequence Number

TDMoIP Payload

IP Header

UDP Header

RTP Header

Control Word

32 Bit

Payload

0x 085E or 2142

Eth

ern

et IP

HeaderTOS

Src adrDst adr

UDPHeader

Src Bundle#

Dst= 0x085E

TDMoIP

Control

Word

Adapated

Payload

(AAL1,AAL2,

HDLC, RAW)

CR

C-3

2

UDP Source Port Number is used as the bundle number designator , UDP Destination port number set to hex 085E (2142) assigned by IANA for TDMoIP.

CBID

20 Bytes

8 Bytes

IP/UDP/RTP Encapsulation


TDMoMPLS packet format

outer label

inner label

controlword

TDMPayload

• Inner and outer labels specify TDM routing and multiplexing• Inner Label contains TDMoMPLS circuit bundle number

• The control word• enables detection of out-of-order and lost packets• indicates critical alarm conditions

• The TDM payload may be adapted• to assist in timing recovery and recovery from packet loss• to ensure proper transfer of TDM signaling• to provide an efficiency vs latency trade-off


FORMID L R Z Length Sequence Number

TDMoIP Payload

Outer Label EXP S TTL

Inner Label = CBID EXP S TTL

MPLS Header

Control Word

Payload

• Example of MPLS Header :

Eth

ern

et

MPLSOuterLabels

MPLSInnerLabel

TDMoIPControlWord

Adapated

Payload

(AAL1,AAL2,

HDLC, RAW)

CR

C-3

2

8 Bytes

MPLS Encapsulation


TDM o L2TPv3

IP header (5*4 B)

Session ID (4 B)

Optional cookie (4 or 8 B)

TDMoIP header (4 B)

TDMoIP payload

Note : No UDP header

higher layers


• Structured TDM Payload

• Multiple AAL1: NxAAL1

• Multiple AAL2: NxAAL2

• HDLC

• UnStructured TDM Payload:

• Bit stream, fixed bytes

TDMoIP Frame

ControlWord

IP/UDP orMPLS header

EhterNetHeader

TDMoIP in Ethernet Frame

FCSTDM Payload


TDMoIP Frame w QoS SupportTDMoIP Frame w QoS Support

MAC Layer IP Layer UDP TDM AAL1 Payload CRC

VLAN Tagging

Priority Labeling

IEEE 802.1p&Q

TOS -Type of ServiceField (Diffserv) Priority

UDP Source & DestinationPorts

2142 (Given by IANA)Level 4 priority

TDMoIPControl Word

Typical 48 Octet Payload AAL1/AAL21 Octet Header 47 Octet payloadUp to 30 AALn Frames in Payload Field

• Header Compression can be used to decrease the header down to a few bytes

• Ethernet Packet Min 64 bytes Max 1536 bytes


TDM Timing Recovery


Introduction

• PSN (e.g. IP) have no clock distribution mechanism

• For TDM over PSN receiver must recover clock– In Band: timing information is transferred over PSN, (e.g., RTP)

• Required high quality reference clock

– Timing information is provided in some means independend of PSN, (e.g., adaptive clock mechanism)

• Recovered clock quality:– Can not guarantee “Quality traffic” if the recovered clock is not accurate

enough– E1: G.823– T1: G.824


Introduction cont.

• Result of RTP can not meet the G.823, G.824– Due to time stamp quantization error, packet loss, ..– Use 12 bytes for RTP– Require reference clock in both side (expensive for high accurate

reference clock)

• Conventional adaptive clock slaves local clock to jitter buffer level– initial frequency discrepancy is eventually compensated– jitter buffer level corresponds to frequency offset

• Although highly robust, there are several faults– entire network jitter transferred to local clock– unstable and vulnerable to packet loss– jitter buffer level may settle far from buffer center– long convergence times


Introduction cont.

TXC PacketTrunk-4 chip's innovative clock recovery scheme • retains robustness of conventional scheme• improved capabilities• Two phases

– acquisition phase• rapid frequency lock is attained.

– tracking phase• the achieved frequency lock is sustained • jitter buffer centering (according to configuration value)• jitter attenuation standards conformance for large PDV• packet loss immunity improved.


Frequency Hold-over

Rx buffer starvation (under-run) can be caused by:• Network congestion • packet loss• In dynamic application when there is no activity• While shifting to an alternate bundle, in redundancy mode

- Last frequency is frozen, until data flow is resumed.- No need for re-acquisition!

• Long-term recovered clock accuracy:– E1/T1: better than 0.02 ppm


Standards


2. PacketTrunk-4


Why TDMoIP?

Complementary to VoIP.

Provides high voice quality with low latency.

Can support all applications that run over E1/T1 circuits, not just voice.

Can be made transparent to protocols and signaling.

An evolutionary – not revolutionary – approach, so investment protection is maximized.


Voice Evolution

Circuit Switching Packet Switching

PSTN ATM IP/MPLS

Leased-Line Service Circuit Emulation Service

TDMoIP/MPLS (CBR)

Switched Voice Service

VoATM (ATM LES) TDMoIP/MPLS (VBR)VoIP


PacketTrunk-4: What is it?

• PacketTrunk-4 enables transparent transport of legacy TDM traffic over IP/MPLS Networks.

• PacketTrunk-4 uses three payload types for TDM transfer over IP/MPLS:– CBR payload type for circuit emulation -- Constant Bit Rate with static allocation of

TDM timeslots)– VBR payload type for loop emulation -- Variable Bit Rate with dynamic allocation of

TDM timeslots– HDLC payload type for efficient transfer or termination of frame based traffic

• PacketTrunk-4 is a highly integrated device for use in a wide variety of applications. It provides a single-chip solution for 4x T1/E1's or 1x T3/E3/STS-1 highly scalable to large multi-chip systems.


Press Release

"RAD Data Communications Partners With TranSwitch Corporation to Develop Innovative

TDM over IP Line for Packet-Switched Networks"

Advanced Devices Will Enable Efficient Voice andData Delivery Over IP/MPLS Carrier and Enterprise Systems

Tel Aviv -- January 7, 2003…


PacketTrunk-4 Block Diagram

PacketTrunk-4

TDMoIP/MPLS Gateway Device

TXC-05870

TDM SIDE

+3.3V

+2.5V

Microprocessor Port

10/100 Ethernet

MII/RMII/ SMII/SSMII

T1/E1/T3/E3/STS-1 Serial 10

10

10

10

Port 1

Port 2

Port 3

Port 4

T1/E1 Serial

19

Buffer SDRAM

Adr/Row/Col

PSN SIDE

Data Ctrl32

Address Data Ctrl JTAG Clocks

24 32 5 238


PacketTrunk-4PacketTrunk-4

PacketTrunk-4 Block Diagram

PayloadEngine

10/100Et MAC

SDRAMController

HostI/F

ClockRecoveryMachines

128Channel

TSI

CASSignalingHandler

Counters &Status Regs

JitterBuffer

Controller

Tx Sig/ Rx Sig

Host Bus16/32 bits

SDRAM Bus32 bits

MII/RMII/

SMII/SSMII1x T3/E3/STS-1or

4x T1/E1/Serial PacketClassifier

QueueManager


PacketTrunk-4 Key Features

• Interfaces– PSTN/Serial: 1x T3/E3/STS-1 or 4x T1/E1/Serial (up to 4.64 Mbps/port,

9.3Mbps aggregate)

– Packet: 1x 10/100 802.3 Ethernet MAC I/F • MII/RMII/SMII/SSMII (half or full duplex)• VLAN tagging and priority labeling per 802.1p & Q

– CPU:• 24-bit address, 16- or 32- bit data bus. • Control/status registers, counters, buffers (for OAM and signaling)

– SDRAM:32 bit. 8 or 16 MB off-chip• Resolution of access to SDRAM: 8, 16, or 32 bit• Controller operates at either 50, 75, or 100 MHz• Support, examples: 64 Mb Micron MT48LC2M32B2TG-6, 128 Mb Micron

MT48LC4M32B2TG-6

– JTAG


PacketTrunk-4 Key Features - Continued

• TDM Payload Types over IP/MPLS– AAL1 un-structured– AAL1 structured– AAL1 structured with CAS– AAL2– HDLC

• User Ports– E3/T3/STS-1: AAL1 unstructured– E1/T1:

• Unframed - E1/T1pass-through: AAL1 unstructured or HDLC payload type• Nx64 Kbps – Fractional T1/E1: AAL1 unstructured & structured, AAL2, HDLC• Structured with CAS – Fractional T1/E1 with CAS: AAL1 structured with CAS or AAL2

– Synchronous Serial Data • Using AAL1 unstructured or HDLC payload type• For continuous bit stream (ex. V.35) or HDLC-based (ex. Frame Relay) transfer.• Single port: up to STS-1 rate (51.84 Mbps)• Four ports: each port can operate at up to 4.64 Mbps with an aggregate rate of 9.3 Mbps• Gapped clock support.


PacketTrunk-4 Key Features - continued

• Support Multiple Bundles and Time-Slot Interchange (TSI) – Supporting up to 128 timeslots. Sub-rate channels of 2, 7, or 8 bits,

as well as Nx64 Kbps (N=1 to 32) are supported in HDLC mode.

– Up to 64 independent bundles,

– assignable via TSI to Payload Engine; or to the host interface. Each bundle has its own:

• Tx and Rx queues • Rx jitter buffers with configurable depth

– T1: up to 256 ms (unframed T1 up to 340 ms)

– E1: up to 256 ms

– T3: up to 46 ms

– E3: up to 60 ms

– STS-1: up to 40 ms

• (CBR mode only) Optional connection-level redundancy; packet payload may be Tx'd twice with two different Ethernet, IP/ MPLS headers. Two different IP addresses may be used for Rx.

• Enable/disable



• Encapsulations:– TDMoIP via CBR or VBR– TDMoMPLS via CBR or VBR– HDLCoIP– HDLCoMPLS

• Clock Recovery– Independent TDM clock recovery per TDM interface for end-to-end TDM sync

through an IP/MPLS network. Recovered clock jitter and wander are standards-compliant (ex. freq accuracy of 1-2 ppm)

– Two major successive phases for CR:• Acquisition phase: attain rapid frequency lock (e.g., less than 10 seconds for a full

E1/T1 bundle)• Tracking phase: sustain the achieved freq lock while gradually bringing the jitter-

buffer level back to its center. Jitter is attenuated to comply with relevant standards

– Conform to G.823/G.824 jitter and wander requirement



• RTOS-independent, abstracted host API source code– Programming the PacketTrunk-4

• Assigning timeslots to bundles• Opening bundles• Closing bundles• Sending frames• Receiving frames• Creation, Configuration, Run time, Status, Deletion…



• Management and Control Plane Functions

– On-chip support of CAS/RBS signaling

• Testing and Loopback– Boundary scan per IEEE 1149.1

• Physical Characteristics– Voltage: 2.5v core, 3.3v I/O.– Size: 27 x 27 mm (1.27 mm pitch)– Package:256-pin PBGA– Power: TBD– Op temp: -40 to +85 C (industrial)


PacketTrunk-4 Key Product Status

• Data Sheet Available

•TDMoIP O’Head calculator Available

• Clock recovery test results Available

• API Spec Available

• Sales Brochure Available

• Demo Board FPGA T1/E1 Only Available

• Tape-out Nov. 17, 2003

• Customer Samples Jan. 16, 2003

• IBIS Model Available

• BSDL File Available


4x T1/E1 PacketTrunk-4 System

PacketTrunk-4

SDRAM

T1/E1 LIU :T1/E1QT1F+

orQE1F+

::

MII/RMII

10/100 EtPHY

CPU

10/100 Et


1x T3/E3/STS-1 PacketTrunk-4 System

PacketTrunk-4

SDRAM

T3/E3/STS-1

MII/RMII

10/100 EtPHY

CPU

DARTor

ARTE

100 Et


1x OC-3/STM-1 PacketTrunk-4 System (T3/E3-Based)

PacketTrunk-4

3xT3/E3

MII/RMII

CPU

TL3MPHAST-3N

CombusSTS-3/STM-1 10/100 Et

Switch10/100 Et

PHY

SDRAM


1x OC-3/STM-1 PacketTrunk-4 System (T1/E1-Based)

PacketTrunk-4

28x T1/21x E1

MII/RMII

10/100 EtSwitch

CPU

TEMx28PHAST-3N

CombusSTS-3/STM-1

10/100 EtPHY

SDRAM

:

:


EStream-8FEEStream-8FE

10/100 EtPHY

10/100 EtPHY

10/100 EtPHY

10/100 EtPHY

Mixed (TDM + Packet Data) Transport over POS

PacketTrunk-4SDRAM

T1/E1 LIU :

T1/E1

:

SMII

PacketTrunk-4SDRAM

SMII

CPU

Envoy-8FE

POS-PHY

10/100 EtPHY

10/100Ethernet

NPU

STS-12c/STM-4c

POS is the predominant optical transport mechanism for packet data.

TEPro:

:

:

:

::

PHAST-12P

POS-PHY


Applications

• Carrier– TDM services over Ethernet MAN

– TDM services over broadband Wireless Ethernet

– TDM services over Cable Ethernet

– 2G / 2.5G cellular backhaul over IP/MPLS

– HDLC-based traffic (ex. Frame Relay) trunking over IP/MPLS

– T/E carrier grooming (via Ethernet backplane)

– PSTN-IP network bridging

• Enterprise– Private line/toll bypass via Ethernet MAN

– TDM PBX migration to Ethernet MAN

– MTU/MDU


TDM over GbE MAN

PublicINTERNET

100 Mbps

TDMoIP GW

CustomerPremise

PBX CustomerPremise

GbE

TDMoIP GW

100 Mbps

PBX

CLASSSwitch

CentralOffice

GbE

TDMoIPGW

TDMoIP GW

POP

IP

TDM LeasedLines

PSTN


Features: TDM concentration (grooming multiple T1/E1 into OC-3/STM-1 trunks) E3/T3 Carrier Trunking

With:GbE Network I/FOC-3/STM-1 TDM interface

TDM Concentration

SDH/SONETCLASS

Switch

PBX

PBX

IP

TDMoIPGW

PSTN

SS7

TDMoIPGW

TDMoIPGW

TDMoIPGW

SDH/SONET

PBX

PBX

IP

ADM

PBX

ADM


Metro MTU Application

POTS

PBX

Switch

TDMoIP GW

TDMoIP GW

SwitchTDMoIPGW

PBX

PBX

PBX

Building LevelIntegration

Office LevelIntegration

PBX

SwitchPBX

TDMoIPGW

PSTN

Corporate Site A

TDMoIP GW

Switch/Router

Corporate Site B

IP/MPLSNetwork


Metro(GbE, IP, RPR,

HFC, EoS)

Cellular Backhaul over IP/EthernetFixed Wireless, Coax, or Fiber Access

FixedWireless

FT1/T1/n*T1

CMTS

FT1/T1/n*T1

Coax

Cell sites w/TDMoIP

blade retrofits

FT1/T1/n*T1Fiber

Switch site w/TDMoIP GW

T1/ T3/ E1100 Mbps

GW GW


GbESwitch

IP Network

SS7 over IP

VoIP GW

User’s needs:

• Transparent SS7 forwarding over IP• Voice transferred as VoIP• Cross Connect functionality

Potential customers:

• Voice carriers• Satellite providers• Cellular operators• MAN providers

PSTN

PublicVoice

Switch

PublicVoice

Switch

GbESwitch

TDMoIP-basedsignaling GW

VoIP GW

SS#7Server

IntelligentNetwork




TDMoIP Summary

• IP and Ethernet network technologies will be dominant in the future.

• Revolutionary VoIP may take more time to mature. Evolutionary solutions that offer a careful migration path are now preferred.

• TDMoIP provides simplicity, transparency, and affordable cost, and that’s actually what the market is looking for.

• PacketTrunk-4 allows the implementation of multi-T1/E1 TDMoIP gateways with enhanced cost/performance for a variety of carrier and enterprise applications across the network.


The PacketTrunk-4 Total Solution

Facilitates a faster time-to-market

Reduces the number of required board level components

Reduces the amount of time spent on design

Reduces development costs

Reduces component costsPacketTrunk-4


Interoperability Tested:

Carriers Who Tested:


TDM Timing Recovery & Measurements


Introduction

• PSN (e.g. IP) have no clock distribution mechanism

• For TDM over PSN receiver must recover clock

• Conventional adaptive clock slaves local clock to jitter buffer level– initial frequency discrepancy is eventually compensated– jitter buffer level corresponds to frequency offset

• Although highly robust, there are several faults– entire network jitter transferred to local clock– unstable and vulnerable to packet loss– jitter buffer level may settle far from buffer center– long convergence times


Introduction cont.

TDMoIP chip's innovative clock recovery scheme • retains robustness of conventional scheme• improved capabilities• Two phases

– acquisition phase• rapid frequency lock is attained.

– tracking phase• the achieved frequency lock is sustained • jitter buffer centering (according to configuration value)• jitter attenuation standards conformance for large PDV• packet loss immunity improved.


Theory of operation

• During acquisition phase– direct estimation of frequency discrepancy drives local clock– band-limited control loop– rapid frequency acquisition (about 10 seconds for full E1/T1 bundle)– capture range 128 ppm for both E1 and T1

• Switch to tracking phase when steady frequency lock detected

• During tracking phase – jitter buffer level drives local clock– band-limited control loop


Features

• Fast frequency acquisition time:– Full E1/T1 bundle (31/24 timeslots): about 10 seconds– Full E3/T3 bundle: about 1 second

• Time for achieving stable phase lock (controlled wander):– Full E1/T1 bundle: a few dozens of seconds– Full E3/T3 bundle: a few seconds

• Long-term recovered clock accuracy:– E1/T1: better than 0.02 ppm– E3/T3: better than 0.05 ppm

• Digital frequency synthesizers jitter generation level:– E1: 0.05 UIpp– T1: 0.02 UIpp

• Digital frequency synthesis resolution is 1 ppm

• Capture range (E1, T1, E3, T3 rates): 128 ppm around nominal

• Full compliance with G.823/G.824 jitter and wander (traffic interface)


Frequency Hold-over

Rx buffer starvation (under-run) can be caused by:• Network congestion • packet loss• In dynamic application when there is no activity• While shifting to an alternate bundle, in redundancy mode

- Last frequency is frozen, until data flow is resumed.- No need for re-acquisition!


Measurements Setup

IPmux-4NETWORKEMULATOR

ETH

ETH

TDMoIP CHIPEVALUATION

BOARD

RECOVEREDTDM CLOCK

ANT-20JITTER AND

WANDERMEASUREMENT

DEVICE

E1

TDM

SOURCE

CLOCK

E1


Measurements Details

Measurement Setup• ANT-20 (Wandel & Goltermann) jitter / wander measurement device sends and

receives TDM signal from both ends• RAD IPmux-4 transmit TDMoIP flow• Network emulator introduces packet loss and PDV (jitter)• TDMoIP Chip evaluation board recovers the clock and reconstruct the original

TDM flow

Network emulator function:• Jitter insertion

Every (configurable) number of packets the flow is halted for an uncorrelated and exponentially distributed random period of time.

• Packet lossA packet is dropped every (configurable) number of packets


Performance - Wander

Wander MRTIE (Max Relative Time Interval Error)

Bundle configuration: E1, 31 timeslots, 48 bytes payload


Performance - Jitter


Network Peak Delay

Variation

[ms]

20 Hz – 100 kHz Bandwid

th[UIpp]

18 kHz – 100 kHz

Bandwidth

[UIpp]

Long-Term

Frequency Offset[ppm/12

hours]0 0.04 0.01 5.5

5 0.07 0.015 3.6

Std. Req. 1.5 0.2


Wander MRTIE (Max Relative Time Interval Error)


Performance - Wander



Network Peak Delay

Variation [ms]

20 Hz – 100 kHz

Bandwidth

[UIpp]

18 kHz – 100 kHz

Bandwidth

[UIpp]

Long-Term

Frequency Offset[ppm/12

hours]5 0.06 0.015 0.2

Performance - Jitter


More Measurements

Jitter measurement: E1, 31 Time Slots, 1 cell (48 payload bytes)/packet for different IPDV levels


More Measurements

Jitter measurement : E1, 31 Time Slots, 1 cell (48 payload bytes)/packet

for the zero IPDV network


More Measurements

Jitter measurement : E1, 31 Time Slots, 5 cells (240 payload bytes)/packet for different IPDV levels


More Measurements

Jitter measurement : E1, 31 Time Slots, 5 cells (240 payload bytes)/packet

for the zero IPDV network


More Measurements

Acquisition behavior: E1, 31 Time Slots, 1 cell (48 payload bytes)/packet for different IPDV levels


More Measurements

Acquisition behavior: E1, 31 Time Slots, 1 cell (48 payload bytes)/packet for zero IPDV levels


More Measurements

Acquisition behavior: E1, 31 Time Slots, 5 cells (240 payload

bytes)/packet for different IPDV levels


More Measurements

Acquisition behavior: E1, 31 Time Slots, 5 cells (240 payload

bytes)/packet for zero IPDV levels


3. PacketTrunk-4 Demo


FXS

FXS

FXS

FXS

PacketTrunk-4 Application Demo TDMoIP and HDLCoIP

Bundle #1TDMoIP (AAL2)

E1

FXS

FXS

FXS

FXS

Sniffer

ETH ETH

IPmux-1

E1

E1

FCD-IP

IP Network

ETH HUB

MLB-E

PacketTrunk-4

Eval-Board

PacketTrunk-4

Eval-Board

Int CLK LBT

LBT

LBTCLK Recovery

FCD-IP

CLK RecoveryBundle #11TDMoIP (AAL1)

Bundle #7HDLCoIP

Traffic Generator and Checker

Assigned TS:Voice – 1, 2HDLC – 17÷31

Assigned TS:Voice – 1, 2

Assigned TS:Voice – 21, 22, 24, 25HDLC – 1÷15

FCD-IP

San Jose

Boston

New York


• Integrated Service:

• Within one E1 (at center side, San Jose): Four phone lines (4 DS0) + one HDLC data channel (15 DS0 time slots grouped together)

• Grooming :

• Using “Bundle” to group multiple DS0 timeslots within the same E1 to form different “bundles” and then deliver to different destinations

• Virtual DS0 Cross-connect :

• Any DS0 time slot at the source end can be virtually cross-connected to the different timeslot at the sink end through the IP network

PacketTrunk-4 Application Demo TDMoIP (AAL1, AAL2) and HDLCoIP


PacketTrunk-4 Application Demo TDMoIP (AAL1, AAL2) and HDLCoIP

• VBR v.s. CBR:

• VBR for SVC channel (Bandwidth is only used when the call is set up; Bandwidth is released when call is disconnected)

• CBR for PVC channel (Bandwidth is constantly used)

• Frequency hold-over activated at the clock recovery circuitry when network connection is broken.

• Clock is recovered instantaneously after network connection is reinstalled

TDMoIP PT4 Intro Cust 020304

Documents

Transcript of TDMoIP PT4 Intro Cust 020304