CS690b Presentation

Multimedia Network ImplementationMultimedia Network Implementation

- Data/Voice Convergence- Data/Voice Convergence

Xianfeng Zeng ( zxf@cs.purdue.edu ) Department of Computer Sciences

Purdue UniversityApril 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/VPNPSTN/VPN

Legacy DataLegacy Data

Frame RelayFrame Relay

TDMTDM

InternetInternet

Remote AccessRemote Access

VPNVPN

Frame RelayFrame Relay

Private ATMPrivate ATM

Public IPPublic IP

1997 - 1998

VPNVPN

EnhancedEnhancedFR/ATMFR/ATM

EnhancedEnhancedPublic IPPublic IP

1999 - 2000

IntegratedIntegratedSingle Single

NetworkNetworkFabricFabric

2000+

Multiservice Evolution

Source: Gartner Group

PSTN Access over IP Service

IP

Phone

PABX

SS7 Signalling allows Carrier Scalability (and reduces cost)

PSTN

3600

AccessServer

LocalExchange

Trunk Interface

TrunkExchange

SS7 Signalling

Q.931

Applications and Services

Phone-to-Phone

3600/2600 3600/2600FXS FXS

IntranetMilano Roma

PBX Trunking

2600/3600/5300 2600/3600/5300E&ME1

E&ME1Intranet

Key System PBXMilano Roma

Real-Time Fax to Fax

2600/3600 2600/3600FXS FXO

Intranet

Milano Londra

Computer or EtherPhone to PSTN

Ethernet

2600/3600/5300

PSTN

H.323Software H.323

Gateway

Applications and Services

Toll BypassMilano Roma

QoSIP Wan

PSTN PSTN

Residential & Business

Residential & Business

LocalCalls

LocalCalls

Applications and Services

PBX Extension

Branch Office Headquarters

PSTN

QoSWAN

(Intranet)V

PBX

V

3640

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 TransparencyFeature Transparency

Via PBX or PSTN

Service InterworkingService Interworking

IP Network

FR Network

PSTN & PBXNetwork

FRAD

Interworking unit

ATM Network

F

A

EDC

B

BillingSystem

Packet to PSTN Gateway Forecast

Total Internet Telephony Gateway Market:WW Unit Shipment & Revenue Forecasts

0

200

400

600

800

1,000

1,200

1,400

1,600

1,800

2,000

1996 1997 1998 1999 2000 2001

Year

Rev

enue

($M

)

0

500

1,000

1,500

2,000

2,500

3,000

Port

Uni

ts (K

)

Revenue ($M)

Port Units (K)

Source: Frost & Sullivan; Internet Telephony Product Markets; #5637-60

Voice Quality: Compression Standards

Unacceptable Utility Business Toll

PCMCellular Voice

Quality

Ban

dwid

th (k

bps)

8

16

24

32

40

48

56

64

0

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 DelayOne Way Delay (msec) (msec)

DescriptionDescription

0–1500–150 Acceptable for Most User ApplicationsAcceptable for Most User Applications

150–400150–400 Acceptable Provided that Acceptable Provided that Administrations Are Aware of the Administrations Are Aware of the Transmission Time Impact on theTransmission Time Impact on theTransmission Quality of User Transmission Quality of User ApplicationsApplications

400+400+ Unacceptable for General Network Unacceptable for General Network Planning Purposes; However, it Is Planning Purposes; However, it Is Recognized that in Some Exceptional Recognized that in Some Exceptional Cases this Limit will Be ExceededCases this Limit will Be Exceeded

ITU G.114 Recommendation

Voice over ATM/FR/IP - 1997Scalability/

Performances

Campus MAN Infrastructure Access

ATM

IPIP

FR

TDM

Campus MAN Infrastructure Access

ATM

IP

FR

TDM

Voice over ATM/FR/IP - 1999Scalability/

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 ITU -T recommendation (2/95)—PICS and abstract test suite for ISDN DSS 1 Layer 3—Circuit and Circuit mode, basic for ISDN DSS 1 Layer 3—Circuit and Circuit mode, basic call control conformance testingcall control conformance testing

Q.931 bisQ.931 bis

ITU-T recommendation (3/93)—Digital Subscriber signalling ITU-T recommendation (3/93)—Digital Subscriber signalling System No. 1 (DSS 1)—ISDN user network interface Layer 3 System No. 1 (DSS 1)—ISDN user network interface Layer 3 specification for basic call controlspecification for basic call control

Q.931Q.931

ITU-T recommendation (3/96)—Coding of speech at 8 kbit/s ITU-T recommendation (3/96)—Coding of speech at 8 kbit/s using conjugate-structure algebraic-code-excited linear-using conjugate-structure algebraic-code-excited linear-predictionprediction

G.729G.729

ITU-T recommendation (3/96)—Dual Rate Speech encoder for ITU-T recommendation (3/96)—Dual Rate Speech encoder for multimedia connections transmitting at 5.3 and 6.3 kbit/smultimedia connections transmitting at 5.3 and 6.3 kbit/s

G.723.1G.723.1

ITU-T recommendation (1988)—ITU-T recommendation (1988)—Pulse Code Modulation (PCM) of voice frequenciesPulse Code Modulation (PCM) of voice frequencies

G.711G.711

StatusStatus

72

PresentationPresentation

SessionSession

TransportTransport

NetworkNetwork

LinkLink

PhysicalPhysical

G.729(A)/G.723(.1)/G.711G.729(A)/G.723(.1)/G.711

H.323/H.323Gateway/SIP/SDPH.323/H.323Gateway/SIP/SDP

RTP/UDP/RSVPRTP/UDP/RSVP

IP/WFQ/IP-precIP/WFQ/IP-prec

MLPPP/FR/ATM AAL1 MLPPP/FR/ATM AAL1

– – –– – –

Voice over IP Protocols

Content of a Conversation

Essential Essential ComponentsComponents

22%22%

Pauses56%

Repetitive22%

Over half of the typical voice call is silence!

StatusStatus

IETF DraftIETF Draft RSVP - Resource ReSerVation Protocol (RSVP)—RSVP - Resource ReSerVation Protocol (RSVP)—Version 1 Functional SpecificationVersion 1 Functional Specification

RFC 1990RFC 1990 IETF RFC 1990 MP: The PPP Multilink Protocol IETF RFC 1990 MP: The PPP Multilink Protocol Obsoletes RFC 1717Obsoletes RFC 1717

IETF RFC 1717 MP: The PPP Multilink ProtocolIETF RFC 1717 MP: The PPP Multilink ProtocolRFC 1717RFC 1717

IETF RFC 1889 RTP: A Transport Protocol for IETF RFC 1889 RTP: A Transport Protocol for Real-Time ApplicationsReal-Time Applications

RFC 1889RFC 1889

ITU-T Recommendation (3/96)—Control Protocol for ITU-T Recommendation (3/96)—Control Protocol for Multimedia CommunicationsMultimedia Communications

H.245H.245

ITU-T Recommendation (11/96)—Visual Telephone ITU-T Recommendation (11/96)—Visual Telephone Systems and Equipment for Local Area Networks Systems and Equipment for Local Area Networks Which Provide a Non-Guaranteed Quality of ServiceWhich Provide a Non-Guaranteed Quality of Service

H.323H.323

VoIP Technologies/Standards

750090_08F8_c1

873301-01

• 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-PhoneH.323 S/W

Branch Office

H.323 Interoperability

Residential

Headquarters

4 to 12 Analog ports

PBX

3640

I-PhoneH.323 S/W

V

QoSWAN

(Intranet)

I-PhoneH.323 S/W

• H.323 VoIP local loop bypass • Integrated messaging: e-mail, v-mail, fax mail• Interoperability with NetMeeting, etc.

V

PSTN

H.324Terminal

H.323 Networking

H.323Gatekeeper

WANRSVP

H.323Terminal

H.323Gateway

H.323Terminal

H.323Terminal

H.323MCU

Scope of H.323

PSTN ISDN

V.70Terminal

SpeechTerminal

H.320Terminal

SpeechTerminal

H.323 Terminal Characteristics

System Control and

User Interface

System ControlH.245

Control

Call Control H.225.0

RAS Control H.225.0

VideoI/O

Equipment

Video CodecH.261, H263

User DataApplications

T.120

H.225.0 Layer

LAN Stack

AudioI/O

Equipment

Scope of

H.323

Audio CodecG.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 ServiceUsing Packet Gateways

ISP “A”

ISP “B”Backbone

V

ISP “A”Backbone

POP (ii)V

QoS Interconnect (or Internet)

V

LocalPSTN

LocalPSTN

LocalPSTN

VoIP Packet Gateway RoadmapQoSWAN

G.729, Group 3 Fax, RTP, RSVPIP over Frame Relay, Leased Lines, ISDN or other WAN links

QoSWAN

36003600

PSTN

Digital (T1/E1/PRI)Voice Interfaces

Residential

H.323 Interoperability

InternetServiceProvider

Trials Q1’98

I-Phone

Service ProviderService Provider

Trials Q1’98

EnterpriseEnterprise

Today V V

PSTN InternetV

V3600

V

AnalogVoice Interfaces

Digital (BRI)Voice Interfaces

ResidentialPOTS Phone

H.323 Interoperability - H.323 VoIP Local Loop Bypass - Resendential and business services- Interoperability with NetMeeting type programs

LocalPSTN

POP

I-PhoneH.323 S/W

QoSWAN

I-PhoneH.323 S/W

xDSLI-Phone

H.323 S/WXDSL

Modem

DSLAM

2nd linephone

PSTN

PBX

V Router+ VoIP

Business

Residential

PBXPBX

V Central Office

InternetResidential

LocalPSTN

VoIP PCM CODERPCM CODER

G.711G.711 64Kbps64Kbps

FXS VoiceFXS VoiceCardCard

VoiceVoiceCompression Compression

VAD VAD etc.etc.

G.729r8G.729r8 8Kbps8Kbps

G.729r8G.729r8 8Kbps8Kbps

FXS VoiceFXS VoiceCardCard

PacketizazionPacketizazionQuality/Class of ServiceQuality/Class of Service

RTP Header CompressionRTP Header Compression

WeightedWeightedFair Queuing, Fair Queuing, IP PrecedenceIP Precedence

RSVP, ecc.RSVP, ecc.

IP WANIP WANLinkLink

Quality PoliciesPlus QualityStandardBest Effort

Voice Integration

Remote Branch

2 AnalogSmall PBX,

POTS

Fax V

CentralHeadquarterPB

X

PSTNCisco 3600

QoSWAN

QoSWANQoS

WAN

Plus QualityStandardBest Effort

t

t

Sender Transmits

Sink Receives

AA BB CC

AA BB CCD1 D2 = D1

Sender Receiver

Network

D3 = D2

Jitter - Delay Variation

• RTP timestamp for jitter estimation • Adaptive jitter buffers in end points

Link IP Link IP WANWAN

Line Protocol ProblemVoice PacketFTP Session Time to :

• High Priority Queue Empty

• The Router starts sending packet from another queue

Jumbogram FTP SessionJumbogram FTP Session

1500 bytes take187ms at 64K

Link IP Link IP WANWAN

Voice PacketFTP Session Time t1 :

• New RTP Packets Come

• It has to wait the FTP Jumbogram to be sent

Jumbogram FTP SessionJumbogram FTP Session

1500 bytes take187ms at 64K

VoIPVoIP

Line Protocol Problem

Link IP Link IP WANWAN

Multilink PPP InterleaveVoice PacketFTP Session Time to :

• High Priority Queue Empty

• The Router starts sending packet fragments from another queue

FTPFTP FTPFTP FTPFTP

Link IP Link IP WANWAN

Multilink PPP InterleaveVoice PacketFTP Session Time t1 :

• New RTP Packets Come

• They are INTERLEAVED between FTP fragments

FTPFTP FTPFTPVoIPVoIPVoIPVoIP

“ INTERLEAVED ”

Algorithm

• Fragment large packets

• Let small packets:Use normal encapsulation

Interleave with fragmented traffic

VoIPVoIP VoIPVoIP

VoIPVoIP VoIPVoIPFTPFTPFTPFTP FTPFTP FTPFTP

Jumbogram FTP SessionJumbogram FTP Session

G.729r8G.729r8 8Kbps8Kbps

RTP Compression

20ms

20 bytes IP Payload20 bytes IP Payload

20 bytes IP Payload20 bytes IP Payload 12 bytes RTP12 bytes RTP

20 bytes IP Payload20 bytes IP Payload 12 bytes RTP12 bytes RTP 8 bytes UDP8 bytes UDP

20 bytes IP Payload20 bytes IP Payload 12 bytes RTP12 bytes RTP 8 bytes UDP8 bytes UDP 20 bytes IP Header20 bytes IP Header

20bytes Payload 40bytes Header

Real Time Protocol Real Time Protocol Header CompressionHeader Compression

G.729r8G.729r8 8Kbps8Kbps

RTP Compression

20ms

20 bytes IP Payload20 bytes IP Payload 12 bytes RTP12 bytes RTP 8 bytes UDP8 bytes UDP 20 bytes IP Header20 bytes IP Header

40bytes Header

23-25 bytes20msec

3-5 bytes 3-5 bytes 20 bytes IP Payload20 bytes IP Payload 9,2Kbps9,2Kbps

Network Architecture

Access

Backbone

Edge FunctionsEdge FunctionsCustomer access aggregation

Policy ApplicationSecurityPacket classification Admission ControlQueuing

Services & traffic metering

Backbone FunctionsBackbone FunctionsHigh speed transport

Congestion management

Queue management

Policy enforcement

Traffic management

POP

POP

POP

POP

Solutions require cooperative edge andbackbone 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

PolicySpecification

Backbone

Network Edge Packet Classifier

Layer 3CAR

Filter

2nd3rdDrop

Per Application CAR1st

2nd

RSVPMultimedia

Mission-Critical

CAR Policy Examples

1st

Drop

1st

2nd

Drop

Firm CAR

CAR & Best Effort

2nd

3rd

Drop

Per Application CAR1st

2nd

2nd

1st

CAR + Premium

RSVPMultimedia

Mission-Critical

The Problem of Congestion

Offered Load

Thro

ughp

ut

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. PremiumMin.

Std MaxPremium

Max

StandardServiceProfile Premium

ServiceProfile

“Slope” is adjustable

Two service levelsare shown; up to 6can be defined.

Num

ber o

f Pac

kets

Dis

card

ed

Putting it All TogetherHigh

Low

Standard

L3 CAR

L3 CAR

Determinepacket class

WRED/WFQ

Access

Core

Solutions require cooperative edge andbackbone functions

Ingress rate thresholds.

Egressrate thresholds

Administerpacket 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

TelephoneNetwork

Gatekeeper

Client H.323Client H.323

RouterProxy

Gatekeeper

Gateway

H.320(Over ISDN)

H.324(Over POTs)

Speech Only(Telephone)

H.323

Corp LAN

H.323 Signaling

H.323

H.323

Q.931

H.245

MediaRTP StreamRTP StreamRTP StreamRTP Stream

RTCP StreamRTCP Stream

Setup

Connect

Open Logical Channel

Gatekeeper

Open Logical Channel Acknowledge

Capabilities Exchange

Admission Request

Admission ConfirmRAS