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

Agenda Overview Data/Voice Convergence Technologies ProblemsProblems Summary

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....

PSTN/VPN Legacy Data Frame Relay TDM Internet Remote Access VPN Frame Relay Private ATM Public IP VPN Enhanced FR/ATM Enhanced Public IP IntegratedSingleNetworkFabric Multiservice Evolution Source: Gartner Group

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

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

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

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

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

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

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

Packet to PSTN Gateway Forecast Source: Frost & Sullivan; Internet Telephony Product Markets; #

Tipo compressione MOS Score Ritardo (msec) PCM (G.711) K ADPCM (G.726) K LD-CELP (G.728) 8K CS-ACELP (G.729) K CS-ACELP (G.729a) 15 Quality Guide Lines3–5

Voice Quality: Compression Standards Unacceptable UtilityBusinessToll PCM Cellular Voice Quality Bandwidth (kbps) ADPCM 32 (G.723) ASPCM 24 (G.725) LDCELP 16 (G.728) ADPCM 16 (G.726) LPC 4.8 CS-ACELP 8 (G.729)

Quality/Delay Issue One Way Delay (msec) Description 0–150 Acceptable for Most User Applications 150–400 Acceptable Provided that Administrations Are Aware of the Transmission Time Impact on the Transmission Quality of User Applications 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

Voice over ATM/FR/IP Scalability/ Performances Campus MANInfrastructureAccess ATM IP FR TDM

Campus MANInfrastructureAccess ATM IP FR TDM Voice over ATM/FR/IP Scalability/ Performances

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

Voice Technologies/Standards 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 Q.931 bis 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 ITU-T recommendation (3/96)—Coding of speech at 8 kbit/s using conjugate-structure algebraic-code-excited linear- prediction G.729 ITU-T recommendation (3/96)—Dual Rate Speech encoder for multimedia connections transmitting at 5.3 and 6.3 kbit/s G ITU-T recommendation (1988)— Pulse Code Modulation (PCM) of voice frequencies G.711 Status 72

PresentationSessionTransportNetworkLinkPhysicalG.729(A)/G.723(.1)/G.711H.323/H.323Gateway/SIP/SDPRTP/UDP/RSVPIP/WFQ/IP-prec MLPPP/FR/ATM AAL1 – – – Voice over IP Protocols

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

Status IETF Draft RSVP - Resource ReSerVation Protocol (RSVP)— Version 1 Functional Specification RFC 1990 IETF RFC 1990 MP: The PPP Multilink Protocol Obsoletes RFC 1717 IETF RFC 1717 MP: The PPP Multilink Protocol RFC 1717 IETF RFC 1889 RTP: A Transport Protocol for Real-Time Applications RFC 1889 ITU-T Recommendation (3/96)—Control Protocol for Multimedia Communications H.245 ITU-T Recommendation (11/96)—Visual Telephone Systems and Equipment for Local Area Networks Which Provide a Non-Guaranteed Quality of Service H.323 VoIP Technologies/Standards _08F8_c

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

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

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

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

Gatekeeper Functions 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

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

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

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

VoIP PCM CODER PCM CODER G Kbps 64Kbps FXS Voice Card VoiceCompression VAD etc. G.729r8 8Kbps 8Kbps

G.729r8 FXS Voice Card Packetizazion Quality/Class of Service RTP Header Compression Weighted Fair Queuing, IP Precedence RSVP, ecc. IP WAN Link Quality Policies Plus Quality Standard Best Effort

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

t t Sender Transmits Sink Receives A BC ABC D1D1 D 2 = D 1 SenderReceiver Network D 3 = D 2 Jitter - Delay Variation RTP timestamp for jitter estimation Adaptive jitter buffers in end points

Queuing’s Premise Getting better service is a matter of managing congested queues Over-all latency and bandwidth are constant Make some traffic absorb latency, and therefore give up bandwidth Shield other traffic from latency, and therefore gain bandwidth

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

Link IP WAN Voice Packet FTP Session Time t 1 : New RTP Packets Come It has to wait the FTP Jumbogram to be sent Jumbogram FTP Session 1500 bytes take 187ms at 64K VoIP Line Protocol Problem

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

Link IP WAN Multilink PPP Interleave Voice Packet FTP Session Time t 1 : New RTP Packets Come They are INTERLEAVED between FTP fragments FTP FTP VoIPVoIP “ INTERLEAVED ”

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

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

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

Network Architecture Access Backbone 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 POP Solutions require cooperative edge and backbone functions. Solutions require cooperative edge and backbone functions.

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

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

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

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

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

Multimedia Conference Manager 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 Proxy Supported ASR interfaces QoS Limit H.323 traffic on the WAN Security * H.323 Multimedia Conference Manager is implemented on Cisco IOS

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

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