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VoIP (Voice Over IP)

VoIP (Voice Over IP). VoIP Network. Gateway functionality is required to adapt the PSTN transmission to IP (the Internet Protocol). Intranet/Internet. Packet Switched Logical Connections. G/W. G/W. Analog Local Loop. Analog Local Loop. Voice Gateway. A gateway provides:

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VoIP (Voice Over IP)

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  1. VoIP (Voice Over IP)

  2. VoIP Network • Gateway functionality is required to adapt the PSTN transmission to IP (the Internet Protocol) Intranet/Internet Packet Switched Logical Connections G/W G/W Analog Local Loop Analog Local Loop

  3. Voice Gateway • A gateway provides: • Signaling - dial tone, call set-up etc. (H.323, MGCP, SS7) • Conversion to IP, (often Ethernet, possibly ATM) • Compression (G.711, G.723.1 etc.) • Echo Cancellation • Quality of Service (QOS) Packet Network

  4. Interfaces Gateway Product PhysicalInterfaces ToneInterfaces SignalingInterfaces Voice/FaxProcessing phone Network Interface EchoCancellation Analogulaw alawlinearpulse dialing 2W/4W loop start ground start gain control Tone Generation DTMFCall Progress Tone CASFXS FXO E & M Transparent CCS Q.931 QSIG Transparent fax modem VAD VoiceCoding PacketNetwork Tone Detection DTMFV.21 Call ProgressMF (R1, R2) Modem Tone PBX Voice Playout DigitalT1/E1 T3 OC1/OC3 KeySystems Fax Modem V.21 V.27ter V.29V.17V.33 DTMF ToneRelay CentralOffice

  5. Voice/Fax Standards Voice over IP H.323 SS7 MGCP SIP TCP/IP Tone detection Echo cancellation (G.165, G.168) Voice codecs V.x modems Voice over Frame Relay FRF.11 Voice over ATM AAL2 Voice over Cable DOCSIS 1.1 MGCP Fax over Packet T.37, T.38

  6. Inter Operability Packet Network Te l e p h o n y I n t e r f a c e Address Translationand Parsing H.323NetworkProtocolInterface Signaling Translation CAS  H.323/FRF.11/ATM CCS  H.323/FRF.11/ATM FRF.11NetworkProtocolInterface Fax Relay/Advanced LocalProcessing ATMStandard In WorkProprietary Today H.323Gateway Gateway Product Network ManagementInterface Functions IP Networks PC w/H.323 Node Prot o c o l S t a c k s Frame RelayGateway Frame Relay Networks ATMGateway ATM Networks

  7. ITU-T Speech Coding Standards 64 kbps 32 kbps 16 kbps 8 kbps 5.3 kbps

  8. Subjective Voice Coder Quality Mean Opinion Score(MOS) Kpbs

  9. VoDSL (VoIP &VoATM) IP IP VoIP VoIP PPP PPP AAL2 AAL5 AAL5 AAL2 VoATM ATM ATM ADSL INTERLEAVED PATH ISP or Core ADSL FAST PATH PLVT PLVT Lifeline POTS Lifeline POTS Access Network DSL Client

  10. TI’s Golden Port • Integrated software with simultaneous support for: • Voice - Fax - V.90 Modem - Signaling

  11. Network Requirements • Scalability - products typically range from 24/30 ports (T1/E1) to thousands of ports • Small Footprint - rack space in central offices and ISP POPs is expensive • Power Consumption - critical for both cost and heat • Cost - cannot afford idle resources • Simultaneous voice relay, fax relay, V.90 modem termination • Non-Blocking • Manageable - accounting and operations

  12. Network Efficient Utilization • Network Type • Bandwidth Utilization • Grade of Service Telogy Software Provides • Choice of low bit rate codecs • Configurable voice packet sizes (10 ms to 80 ms) • Efficient Voice Activity Detector (VAD) • Fax demodulation/remodulation • Ability to restrict max fax transmission rate, e.g., 2400, 4800, 9600 bps • Sub-Channel Multiplexing - FRF.11

  13. Universal Access Recurring Cost Discrete Trunks Capital Cost Idle Equipment • PSTN Replacement requires support for Voice, Fax and V.90 Modem Packet Network

  14. Channel Density • Multi-Instance - ability of software to support multiple modems in same DSP • Old software base hard-coded for single channel operation; difficult to migrate to multi-channel • Software designed for multi-channel operation from its inception results in a more robust product • Critical decisions on MIPS and memory vs. modem performance tradeoffs • Skimping here will result in a poor performing solution

  15. Hardware Architecture • Multi-processor • Maximizes scalability • Real time call discrimination • Eliminates the requirement for discrete trunks

  16. Multi ProcessorT1/E1 Building Block • RISC Processor • Modem Control Processing DSP DSP DSP DSP • Digital Signal Processor(s) (DSP) • Voice Compression • Tone Detection/Generation • Echo Cancellation • Silence Suppression • Fax Modem • V.90 Data Modem PSTN Trunks Ethernet (Internet) • CISC or RISC Processor • Telephony Protocols • Network Protocols • Management • Routing • Billing

  17. Dynamic Call Discrimination CISC RISC DSP DSP DSP DSP • Determines on a call by call basis if the calling “device” is a Human, Fax Machine, or a Modem • Tone Detection • Flag Detection • Called number parsing Ethernet (Internet)

  18. Echo Cancellation 1,920 Miles 960 Miles 480 Miles 60 Miles Gateway PBX CO Switch with echo canceller 1 ms 8 ms 16 ms 32 ms • Every 60 miles between the Gateway’s echo canceller and the reflecting hybrid requires 1 ms of echo tail Telogy Software provides selectable tail length from 8 ms to 128 ms, G.165, G.168 compliant

  19. Packet Loss Voice/Fax PlayoutBuffer • Telogy Voice Software Provides: • Lost packet compensation for all codecs • Lost packet statistics • Peak MIPS design philosophy • Telogy Fax Software Provides: • Control packet redundancy to correct for lost packets • Advanced local processing to negate the effects of network problems • Very high call completion rates (100% at 5%; 97% at 10) • Lost Packets Due to: • Network Congestion/Performance • Network Architecture • Improper Jitter Buffer Size • Software Not Designed for Peak Load • Potential Causes of Packet Reordering: • Network Congestion/Performance • Network Architecture GatewayProduct GatewayProduct Packet Network 5 4 2 1 6 3 Lost Lost

  20. Real-Time Fax Gateway Packet Network 64K bps 64K bps 14.4 Kbps • Emulates the Central Office and the remote fax machine (fax modem) • Demodulates the fax transmission and extracts the fax data • Encapsulates the fax data • Transmits the fax data in packets • Remodulates the fax data for transmission to the remote fax machine

  21. Success Factors for Fax over Packet Networks

  22. Fax Latency Network FTE endstransmission andstarts T4 timer Delay Delay Timeout occurswithout receiving areply and FTE startsretransmission oforiginal message. Retransmission from Originating FTE “collides” with reply from Destination FTE Destination FTE Originating FTE FIU FIU Duration ofT.4 timer(per T.30)

  23. Technique To Keep Call Alive Destination FTE Originating FTE FIU FIU Network FTE endstransmission andstarts T4 timer Delay Delay Before timeout at Originating FTE, FIU starts sending “preamble” fill signal in anticipation of receiving message over network. Message arrives over network. FIU remodulatesmessage as it is received. Duration of T.4 timer(per T.30)

  24. Difference Between a Good Modem and aGreat Modem • Key Algorithms - where some vendors cut corners • Echo Canceller and Equalizer • Structure, speed and level of convergence, length • Full vs. Reduced Complexity Viterbi decoder • Handshaking sequence • Works reliably in channel impairment situations • Full channel analysis • Smart optimization techniques

  25. Network Management Challenges Quality Measurement • Packet Loss • Latency • Jitter Supervisory Measurement • Call Accounting • Call Type Configuration • Address Translation • Signaling Mode • Network Environment Parameters Telogy Software Provides • Quality statistics • Supervisory statistics • Online configuration • Complete SNMP MIB for VOP

  26. Network Management Diagnostics • VOICE MON - Voice Packet Software Monitor • PCM trace capability • Loop back capability • Signal level measurements • Playout statistics • Memory dump facility • SIG MON - Micro Signaling Trace Monitor • Real-time trace capability • Controllable levels of tracing • All significant events including state changes, etc. • Customer can route output to Monitoring System • V. MON - Modem Monitor • Real-time trace capability • Configuration options • Statistics • Status • FAX MON - Fax Software Monitor • Real-time fax trace • All significant events • Millisecond accuracy on timestamping • Compress format interpreted by PC software

  27. Software Scalability Client Products Access Products Infrastructure Products Telogy Software Client Suite Low Density Multi-Function Telogy Software Access Suite Multi-Channel Multi-Function Telogy Software Infrastructure Suite High Density Broad range of capabilities What to Look For: • Pre-integrated hardware and software scaling from One to Thousands of ports • Optimized solutions and cost for all market areas • Synchronized feature migration

  28. Intellectual Property • It’s a Standards-Based World • G.728, G.729, G.723.1, etc. • V.90, V.34, etc. • Intellectual Property • Critical Success Factor for Marketplace Success • Now at forefront of Customer focus • Key Competitive Issue • Affects product costs • Liability Patents 101

  29. Traditional Telephony • Telephones and Fax Machines connect directly with each other over time division multiplexed circuits Lahore Karachi

  30. Central Office • Connections are managed by Central Office Switches and Enterprise PBXs • Route calls onto digital trunks • Provide billing information (Call Detail Records - CDRs) • Provide management information (Alarms, Usage etc.) Analog Local Loop Analog Local Loop Circuit Switched Digital Trunks

  31. Modems • Analog Modem calls are made in the same way as PSTN voice and fax calls Circuit Switched Digital Trunks Analog Local Loop Analog Local Loop

  32. Modems and the Internet/Intranet • PC Client to WEB Server rather than Peer to Peer • Many clients connecting through each POP • Digital access trunks required to be operationally economical • Remote Access Servers (RAS) • An integration of Digital Modems and IP Router POP Packet Network WEB Server Remote Access Server

  33. Basics-Analog Voice to PCM An analog voice signal is received The Signal is converted to a Pulse Code Modulation(PCM) digital stream 10110101 11010011 11001001 00100100 00111100 10010011 11100001 00100100

  34. Basics-PCM to Frames And Voice frames are created 10110101 11010011 11001001 00100100 00111100 10010011 11100001 00100100 00111100 Each Frame is 10 ms long (G.729a) and contains 10 bytes of “speech” 10110101 The PCM stream is fed into the CODEC 11010011 11001001 00100100 00111100 10010011 11100001 00100100 00111100

  35. Summary • Carrying Voice, Fax and Data over Packet networks provides the most bandwidth efficient method of integrating divergent technologies • While the challenges to this integration are substantial, the expanded market addressed by Telogy’s Golden Port make universal port implementations your best choice

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