tdmoip pt4 intro cust 020304
TRANSCRIPT
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
TranSwitch Corporation Proprietary & Confidential 3
1. TDMoIP: Introduction
TranSwitch Corporation Proprietary & Confidential 4
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)
TranSwitch Corporation Proprietary & Confidential 5
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
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Emulating TDM
From PSTN to PSN
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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
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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
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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
TranSwitch Corporation Proprietary & Confidential 10
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
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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
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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
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TDMoIP Protocol Processing
Traffic Types:
• Structured (framed)
• Unstructured (unframed)
TDMframes
TDMframes
IP Packets
PSN
IP Packets
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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
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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”
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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
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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 @
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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)
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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
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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
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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!
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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
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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
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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
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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
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TDMoIP encap formats- For UnStructured Traffic(SATOP: Draft-ietf-pwe3-satop)
SATOP: Structue-agnostic TDM over Packet)
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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
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TDMoIP encap formatsSummary
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TDMoIP layering structure
PSN / multiplexing
Optional RTP header
TDMoIP Encapsulation
TDM Over IP Payload
higher layers
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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
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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
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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
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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
TranSwitch Corporation Proprietary & Confidential 34
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
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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
TranSwitch Corporation Proprietary & Confidential 36
• 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
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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
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TDM Timing Recovery
TranSwitch Corporation Proprietary & Confidential 39
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
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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
TranSwitch Corporation Proprietary & Confidential 41
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.
TranSwitch Corporation Proprietary & Confidential 42
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
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Standards
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2. PacketTrunk-4
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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.
TranSwitch Corporation Proprietary & Confidential 46
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
TranSwitch Corporation Proprietary & Confidential 47
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.
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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…
TranSwitch Corporation Proprietary & Confidential 49
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
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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
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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
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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.
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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
TranSwitch Corporation Proprietary & Confidential 54
PacketTrunk-4 Key Features - continued
• 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
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PacketTrunk-4 Key Features - continued
• 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…
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PacketTrunk-4 Key Features - continued
• 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)
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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
TranSwitch Corporation Proprietary & Confidential 58
4x T1/E1 PacketTrunk-4 System
PacketTrunk-4
SDRAM
T1/E1 LIU :T1/E1QT1F+
orQE1F+
::
MII/RMII
10/100 EtPHY
CPU
10/100 Et
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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
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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
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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
:
:
TranSwitch Corporation Proprietary & Confidential 62
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
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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
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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
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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
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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
TranSwitch Corporation Proprietary & Confidential 67
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
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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-basedsignaling GW
TDMoIP-basedsignaling GW
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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.
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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
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Interoperability Tested:
Carriers Who Tested:
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TDM Timing Recovery & Measurements
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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
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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.
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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
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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)
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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!
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Measurements Setup
IPmux-4NETWORKEMULATOR
ETH
ETH
TDMoIP CHIPEVALUATION
BOARD
RECOVEREDTDM CLOCK
ANT-20JITTER AND
WANDERMEASUREMENT
DEVICE
E1
TDM
SOURCE
CLOCK
E1
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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
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Performance - Wander
Wander MRTIE (Max Relative Time Interval Error)
Bundle configuration: E1, 31 timeslots, 48 bytes payload
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Performance - Jitter
Bundle configuration: E1, 31 timeslots, 48 bytes payload
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
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Wander MRTIE (Max Relative Time Interval Error)
Bundle configuration: E1, 4 timeslots, 48 bytes payload
Performance - Wander
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Bundle configuration: E1, 4 timeslots, 48 bytes payload
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
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More Measurements
Jitter measurement: E1, 31 Time Slots, 1 cell (48 payload bytes)/packet for different IPDV levels
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More Measurements
Jitter measurement : E1, 31 Time Slots, 1 cell (48 payload bytes)/packet
for the zero IPDV network
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More Measurements
Jitter measurement : E1, 31 Time Slots, 5 cells (240 payload bytes)/packet for different IPDV levels
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More Measurements
Jitter measurement : E1, 31 Time Slots, 5 cells (240 payload bytes)/packet
for the zero IPDV network
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More Measurements
Acquisition behavior: E1, 31 Time Slots, 1 cell (48 payload bytes)/packet for different IPDV levels
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More Measurements
Acquisition behavior: E1, 31 Time Slots, 1 cell (48 payload bytes)/packet for zero IPDV levels
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More Measurements
Acquisition behavior: E1, 31 Time Slots, 5 cells (240 payload
bytes)/packet for different IPDV levels
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More Measurements
Acquisition behavior: E1, 31 Time Slots, 5 cells (240 payload
bytes)/packet for zero IPDV levels
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3. PacketTrunk-4 Demo
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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
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• 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
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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