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CS690b Presentation

CS690b Presentation. Multimedia Network Implementation - Data/Voice Convergence. Xianfeng Zeng ( zxf@cs.purdue.edu ) Department of Computer Sciences Purdue University April 1,1999. Agenda. Overview

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CS690b Presentation

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  1. CS690b Presentation Multimedia Network Implementation - Data/Voice Convergence Xianfeng Zeng ( zxf@cs.purdue.edu ) Department of Computer Sciences Purdue University April 1,1999

  2. Agenda • Overview • Data/Voice Convergence Technologies • Problems • Summary

  3. Why Voice/Data Convergence ? • Huge growth of Data/IP WAN traffic • Integrated Networks is cheaper to manage • Shared infrastructure - redundancy • Voice Processing is now economical • Voice compression algorithms give good quality at 8Kbps and DSPs have come down in price • Potential for reducing WAN costs integrating Voice and Data • Standards and Deregulation are here or are close • Voice over ATM, Voice over Frame Relay, Voice over IP • Voice compression, echo, jitter, etc....

  4. VPN PSTN/VPN VPN Legacy Data Integrated Single Network Fabric EnhancedFR/ATM Frame Relay Frame Relay Private ATM TDM Internet EnhancedPublic IP Public IP Remote Access 1997 - 1998 2000+ 1999 - 2000 Multiservice Evolution Source: Gartner Group

  5. PSTN Access over IP Service SS7 Signalling allows Carrier Scalability (and reduces cost) IP Access Server Phone Q.931 3600 SS7 Signalling PABX Local Exchange Trunk Interface Trunk Exchange PSTN

  6. Phone-to-Phone 3600/2600 3600/2600 FXS FXS Intranet Milano Roma PBX Trunking 2600/3600/5300 2600/3600/5300 E&M E1 E&M E1 Intranet Roma Milano Key System PBX Applications and Services

  7. Applications and Services Real-Time Fax to Fax 2600/3600 2600/3600 FXS FXO Intranet Londra Milano Computer or EtherPhone to PSTN H.323 Software H.323 Gateway Ethernet PSTN 2600/3600/5300

  8. Applications and Services Toll Bypass QoS IP Wan PSTN PSTN Local Calls Local Calls Residential & Business Residential & Business Milano Roma

  9. V V PBX Extension 3640 PBX PSTN QoS WAN (Intranet) 3640 Branch Office Headquarters

  10. Challenge • Have to understand both Voice networking and Data networking • Developing QoS networks and functionality • Voice quality is hard to guarantee • Need solutions (architecture) to move Voice from analog to data network quicker

  11. The Service Challenge Feature Transparency IP/FR/ATM Network Via PBX or PSTN Service Interworking PSTN & PBX Network B IP Network F E FRAD D C FR Network A Billing System ATM Network Interworking unit

  12. Packet to PSTN Gateway Forecast Source: Frost & Sullivan; Internet Telephony Product Markets; #5637-60

  13. Utility Business Toll Unacceptable 64 Cellular Voice PCM 56 48 Bandwidth (kbps) 40 ADPCM 32(G.723) 32 ASPCM 24(G.725) 24 ADPCM 16(G.726) LDCELP 16(G.728) 16 CS-ACELP 8(G.729) LPC 4.8 8 0 Quality Voice Quality: Compression Standards

  14. Quality/Delay Issue One Way Delay (msec) Description 0–150 Acceptable for Most User Applications Acceptable Provided that Administrations Are Aware of the Transmission Time Impact on theTransmission Quality of User Applications 150–400 400+ Unacceptable for General Network Planning Purposes; However, it Is Recognized that in Some Exceptional Cases this Limit will Be Exceeded ITU G.114 Recommendation

  15. Voice over ATM/FR/IP - 1997 Scalability/ Performances ATM FR IP IP TDM Campus MAN Infrastructure Access

  16. Voice over ATM/FR/IP - 1999 Scalability/ Performances ATM IP FR TDM Campus MAN Infrastructure Access

  17. Standards & Organizations • ITU-T—H.323 • IMTC—VoIP ( International Multimedia Teleconferencing Consortium) • IETF—RSVP,WFQ, RED, RTP • FRF—VoFR FRF.11 FRF.12

  18. Voice Technologies/Standards Status G.711 ITU-T recommendation (1988)—Pulse Code Modulation (PCM) of voice frequencies G.723.1 ITU-T recommendation (3/96)—Dual Rate Speech encoder for multimedia connections transmitting at 5.3 and 6.3 kbit/s G.729 ITU-T recommendation (3/96)—Coding of speech at 8 kbit/s using conjugate-structure algebraic-code-excited linear-prediction Q.931 ITU-T recommendation (3/93)—Digital Subscriber signalling System No. 1 (DSS 1)—ISDN user network interface Layer 3 specification for basic call control Q.931 bis ITU -T recommendation (2/95)—PICS and abstract test suite for ISDN DSS 1 Layer 3—Circuit and Circuit mode, basic call control conformance testing 72

  19. Voice over IP Protocols Presentation Session Transport Network Link Physical G.729(A)/G.723(.1)/G.711 H.323/H.323Gateway/SIP/SDP RTP/UDP/RSVP IP/WFQ/IP-prec MLPPP/FR/ATM AAL1 – – –

  20. Content of a Conversation Essential Components 22% Repetitive 22% Pauses 56% Over half of the typical voice call is silence!

  21. VoIP Technologies/Standards Status H.323 ITU-T Recommendation (11/96)—Visual Telephone Systems and Equipment for Local Area Networks Which Provide a Non-Guaranteed Quality of Service H.245 ITU-T Recommendation (3/96)—Control Protocol for Multimedia Communications RFC 1889 IETF RFC 1889 RTP: A Transport Protocol for Real-Time Applications RFC 1717 IETF RFC 1717 MP: The PPP Multilink Protocol RFC 1990 IETF RFC 1990 MP: The PPP Multilink Protocol Obsoletes RFC 1717 IETF Draft RSVP - Resource ReSerVation Protocol (RSVP)—Version 1 Functional Specification 0090_08F8_c1873301-01 75

  22. RTP - RFC 1889 • RTP “ Real-time Transfer Protocol “ • Small, real time data packets - Connectionless environment • RTCP “ Real-time Transfer Control Protocol “ • Provides feedback on current network conditions

  23. V V H.323 Interoperability PBX PSTN I-Phone H.323 S/W Residential PBX 4 to 12 Analog ports QoS WAN (Intranet) 3640 3620 I-Phone H.323 S/W I-Phone H.323 S/W Headquarters Branch Office • H.323 VoIP local loop bypass • Integrated messaging: e-mail, v-mail, fax mail • Interoperability with NetMeeting, etc.

  24. H.323 Networking H.323 MCU H.323 Terminal H.323 Terminal Scope of H.323 WAN RSVP H.323 Gatekeeper H.323 Terminal H.323 Gateway PSTN ISDN V.70 Terminal H.324 Terminal Speech Terminal H.320 Terminal Speech Terminal

  25. H.323 Terminal Characteristics System Control and User Interface Video I/O Equipment Audio I/O Equipment User Data Applications T.120 System Control Audio Codec G.711, G.722, G.723, G.723.1, G.728, G.729 H.245 Control Video Codec H.261, H263 Scope of H.323 Call Control H.225.0 RAS Control H.225.0 Receive Path Delay H.225.0 Layer LAN Stack

  26. Mandatory services: Address translation Admissions control Bandwidth control Zone management Optional services: Call control signalling Call authorization Bandwidth management and reservation Call management Gatekeeper management information data structure Directory services Gatekeeper Functions

  27. Local PSTN V QoS Interconnect (or Internet) ISP “A” Backbone ISP “B” Backbone V Local PSTN Local PSTN V POP (ii) Public VoIP ServiceUsing Packet Gateways ISP “A” Settlement Provider (Trusted 3rd Party) Authentication, Call Routing, Billing and Settlement Server ISP “B” POP (i)

  28. V V V V V VoIP Packet Gateway Roadmap Enterprise • G.729, Group 3 Fax, RTP, RSVP • IP over Frame Relay, Leased Lines, ISDN or other WAN links QoS WAN 3600 Today 3600 PSTN Analog Voice Interfaces QoS WAN 3600 Trials Q1’98 Digital (T1/E1/PRI) Voice Interfaces Digital (BRI) Voice Interfaces Service Provider PSTN Trials Q1’98 Internet Residential I-Phone Internet Service Provider H.323 Interoperability Residential POTS Phone

  29. PBX H.323 Interoperability • - H.323 VoIP Local Loop Bypass - Resendential and business services- Interoperability with NetMeeting type programs Business PSTN PBX I-Phone H.323 S/W Router + VoIP V QoS WAN V Central Office POP Local PSTN I-Phone H.323 S/W Internet Residential DSLAM xDSL I-Phone H.323 S/W XDSL Modem 2nd line phone Local PSTN Residential

  30. FXS Voice Card VoIP Voice Compression VAD etc. PCM CODER G.729r8 8Kbps G.711 64Kbps

  31. Plus Quality Standard Best Effort G.729r8 8Kbps FXS Voice Card Quality Policies Packetizazion Quality/Class of Service RTP Header Compression WeightedFair Queuing, IP PrecedenceRSVP, ecc. IP WAN Link

  32. PBX Plus Quality Standard Best Effort Voice Integration QoS WAN QoS WAN QoS WAN Central Headquarter Small PBX, POTS 2 Analog V Fax Cisco 3600 PSTN Remote Branch

  33. Jitter - Delay Variation Sender Receiver Network B C A Sender Transmits t A B C Sink Receives D3 = D2 D1 D2 = D1 t • RTP timestamp for jitter estimation • Adaptive jitter buffers in end points

  34. Voice Packet FTP Session 1500 bytes take 187ms at 64K Jumbogram FTP Session Line Protocol Problem Time to : • High Priority Queue Empty • The Router starts sending • packet from another queue Link IP WAN

  35. Voice Packet FTP Session 1500 bytes take 187ms at 64K Jumbogram FTP Session VoIP Line Protocol Problem Time t1 : • New RTP Packets Come • It has to wait the FTP • Jumbogram to be sent Link IP WAN

  36. Voice Packet FTP Session FTP FTP FTP Multilink PPP Interleave Time to : • High Priority Queue Empty • The Router starts sending • packet fragments from • another queue Link IP WAN

  37. Voice Packet FTP Session FTP FTP VoIP VoIP Multilink PPP Interleave Time t1 : • New RTP Packets Come • They are INTERLEAVED • between FTP fragments “ INTERLEAVED ” Link IP WAN

  38. Algorithm VoIP Jumbogram FTP Session VoIP FTP FTP VoIP FTP VoIP FTP • Fragment large packets • Let small packets: • Use normal encapsulation • Interleave with fragmented traffic

  39. G.729r8 8Kbps 20ms 20 bytes IP Payload 20 bytes IP Payload 12 bytes RTP 20 bytes IP Payload 8 bytes UDP 12 bytes RTP 20 bytes IP Payload 8 bytes UDP 12 bytes RTP 20 bytes IP Header 20bytes Payload 40bytes Header RTP Compression

  40. G.729r8 8Kbps 20ms 40bytes Header 20 bytes IP Payload 12 bytes RTP 20 bytes IP Header 8 bytes UDP 20 bytes IP Payload 3-5 bytes 23-25 bytes 20msec RTP Compression Real Time Protocol Header Compression 9,2Kbps

  41. POP POP POP POP Network Architecture Access Backbone Solutions require cooperative edge and backbone functions. • Edge Functions • Customer access aggregation • Policy Application • Security • Packet classification • Admission Control • Queuing • Services & traffic metering • Backbone Functions • High speed transport • Congestion management • Queue management • Policy enforcement • Traffic management

  42. Backbone Layer 3 CAR Filter RSVP Multimedia Drop 3rd 2nd 2nd Mission-Critical 1st Per Application CAR Packet Classification Policy Specification Network Edge Packet Classifier Customer Premise • Up to 6 Traffic Classes via TOS bits • Classification by Port, IP Address, • or Application Port • Network or Customer Assignment

  43. CAR Policy Examples 1st Drop 2nd 1st CAR + Premium Firm CAR RSVP Multimedia Drop Drop 3rd 2nd 2nd 1st 2nd Mission-Critical 1st CAR & Best Effort Per Application CAR

  44. Congestion Management Goals • Max Goodput and Min. Delay • Scale to High Speed Nets • Fairness • Accommodates IP Burstiness • Preserves Traffic Classes • Avoids Global Synchronization The Problem of Congestion Managed Congestion Throughput Uncontrolled Congestion Offered Load

  45. WRED Service Profile Example Two service levels are shown; up to 6 can be defined. Number of Packets Discarded Standard Service Profile Premium Service Profile “Slope” is adjustable Std Min. Premium Min. Std Max Queue Length Premium Max

  46. Access High Standard Low Core Putting it All Together Solutions require cooperative edge and backbone functions L3 CAR L3 CAR WRED/WFQ Administer packet class Egressrate thresholds Ingress rate thresholds. Determine packet class

  47. Multimedia Conference Manager • Proxy • Supported ASR interfaces • QoS • Limit H.323 traffic on the WAN • Security • Gatekeeper • Zone definition • Bandwidth management • Authentication • Making calls with in a zone • Making calls to H.323 devices • out side the Gatekeeper Zone • Remote zone Gatekeeper lookup • Accounting • Address resolution * H.323 Multimedia Conference Manager is implemented on Cisco IOS

  48. H.323 Infrastructure Gatekeeper Client H.323 Client H.323 Corp LAN Router Gateway Proxy Gatekeeper H.320(Over ISDN) TelephoneNetwork Real-time Network H.324(Over POTs) Internet Speech Only (Telephone) H.323

  49. H.323 Gatekeeper H.323 H.323 Signaling Admission Request RAS Admission Confirm Setup Q.931 Connect Capabilities Exchange Open Logical Channel H.245 Open Logical Channel Acknowledge RTP Stream Media RTP Stream RTCP Stream

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