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CS690b PresentationCS690b Presentation
Multimedia Network ImplementationMultimedia Network Implementation
- Data/Voice Convergence- Data/Voice Convergence
Multimedia Network ImplementationMultimedia Network Implementation
- Data/Voice Convergence- Data/Voice Convergence
Xianfeng Zeng ( [email protected] ) Department of Computer Sciences
Purdue UniversityApril 1,1999
Xianfeng Zeng ( [email protected] ) Department of Computer Sciences
Purdue UniversityApril 1,1999
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 3600/2600
FXS FXS
Intranet
Milano Roma
PBX Trunking
2600/3600/5300 2600/3600/5300E&ME1
E&ME1Intranet
Key System PBXMilano Roma
Real-Time Fax to Fax
2600/3600 2600/3600
FXS FXOIntranet
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
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
E
DC
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
Re
ve
nu
e (
$M)
0
500
1,000
1,500
2,000
2,500
3,000
Po
rt U
nit
s (K
)
Revenue ($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
dw
idth
(kb
ps)
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 - 1997
Scalability/Performances
Campus MAN Infrastructure Access
ATM
IPIP
FR
TDM
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
VV
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.
VV
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 Control
H.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
VV
ISP “A”Backbone
POP (ii)
VV
QoS Interconnect (or Internet)
VV
LocalPSTN
LocalPSTN
LocalPSTN
VoIP Packet Gateway Roadmap
QoSWAN
G.729, Group 3 Fax, RTP, RSVP
IP 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
V
3600V
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 Analog
Small PBX, POTS
Fax V
CentralHeadquarterPB
X
PSTN
Cisco 3600
QoSWAN
QoSWAN
QoSWAN
Plus QualityStandardBest Effort
t
t
Sender Transmits
Sink Receives
AA BB CC
AA BB CC
D1 D2 = D1
Sender Receiver
Network
D3 = D2D3 = 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 Functions
Customer access aggregation
Policy ApplicationSecurityPacket classification Admission ControlQueuing
Services & traffic metering
Backbone FunctionsBackbone Functions
High speed transport
Congestion management
Queue management
Policy enforcement
Traffic management
POP
POP
POP
POP
Solutions require cooperative edge andbackbone functions.
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
Network Edge Packet Classifier
Layer 3CAR
Filter
Layer 3CAR
Filter
2nd3rd
Drop
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
Th
rou
gh
pu
t
Managed CongestionManaged Congestion
Uncontrolled CongestionUncontrolled 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.
Two service levelsare shown; up to 6can be defined.
Nu
mb
er o
f P
acke
ts D
isca
rded
Putting it All Together
High
Low
Standard
L3 CAR
L3 CAR
Determinepacket class
Determinepacket class
WRED/WFQ
Access
Core
Solutions require cooperative edge andbackbone functions
Solutions require cooperative edge andbackbone functions
Ingress rate thresholds.Ingress rate thresholds.
Egressrate thresholdsEgressrate thresholds
Administerpacket classAdministerpacket 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