Download Cisco Voice Programs - In Search of a Strategy

CS690b Presentation
Multimedia Network Implementation
- Data/Voice Convergence
Xianfeng Zeng ( [email protected] )
Department of Computer Sciences
Purdue University
April 1,1999
Agenda
• Overview
• Data/Voice Convergence Technologies
• Problems
• 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....
Multiservice Evolution
PSTN/VPN
VPN
VPN
Legacy Data
Frame Relay
Frame Relay
TDM
Private ATM
Internet
Remote Access
Source: Gartner Group
Enhanced
FR/ATM
Public IP
Enhanced
Public IP
1997 - 1998
1999 - 2000
Integrated
Single
Network
Fabric
2000+
PSTN Access over IP Service
SS7 Signalling allows Carrier Scalability (and reduces cost)
IP
Access
Server
Q.931
Phone
3600
SS7 Signalling
PABX
Local
Exchange
Trunk Interface
Trunk
Exchange
PSTN
Applications and Services
Phone-to-Phone
3600/2600
3600/2600
FXS
FXS
Intranet
Milano
Roma
PBX Trunking
2600/3600/5300
2600/3600/5300
E&M
E&M
E1
E1
Intranet
Key System
Milano
Roma
PBX
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
2600/3600/5300
PSTN
Applications and Services
Toll Bypass
Milano
Roma
QoS
IP Wan
PSTN
PSTN
Local
Calls
Residential
& Business
Local
Calls
Residential
& Business
PBX Extension
3640
PBX
V
PSTN
QoS
WAN
(Intranet)
V
3640
Branch Office
Headquarters
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
Feature Transparency
IP/FR/ATM Network
Via PBX or PSTN
Service Interworking
PSTN & PBX
Network
B
IP Network
F
E
FRAD
FR Network
C
A
ATM Network
Interworking unit
D
Billing
System
Packet to PSTN Gateway Forecast
Total Internet Telephony Gateway Market:
WW Unit Shipment & Revenue Forecasts
2,000
3,000
Revenue ($M)
1,800
Port Units (K)
2,500
1,600
2,000
1,200
1,000
1,500
800
1,000
600
400
500
200
0
0
1996
1997
1998
1999
Year
Source: Frost & Sullivan; Internet Telephony Product Markets; #5637-60
2000
2001
Port Units (K)
Revenue ($M)
1,400
Voice Quality: Compression Standards
Unacceptable
Utility
Business
Toll
64
48
40
32
Bandwidth (kbps)
56
Cellular Voice
ADPCM 32
(G.723)
ASPCM 24
(G.725)
24
ADPCM 16
(G.726)
16
8
LPC 4.8
PCM
LDCELP 16
(G.728)
CS-ACELP 8
(G.729)
0
Quality
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 - 1997
Scalability/
Performances
ATM
IP
IP
Campus
TDM
MAN
Infrastructure
Access
FR
Voice over ATM/FR/IP - 1999
Scalability/
Performances
ATM
IP
FR
TDM
Campus
MAN
Infrastructure
Access
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
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 linearprediction
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
Voice over IP Protocols
Presentation
Session
G.729(A)/G.723(.1)/G.711
H.323/H.323Gateway/SIP/SDP
Transport
RTP/UDP/RSVP
Network
IP/WFQ/IP-prec
Link
Physical
MLPPP/FR/ATM AAL1
–––
Content of a Conversation
Essential
Components
22%
Repetitive
22%
Pauses
56%
Over half of the typical voice call is silence!
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_c1
873301-01
75
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
H.323 Interoperability
PBX
I-Phone
H.323 S/W
PSTN
Residential
PBX
4 to 12
Analog ports
QoS
WAN
(Intranet)
3620
V
V
3640
I-Phone
H.323 S/W
I-Phone
H.323 S/W
Branch Office
Headquarters
• H.323 VoIP local loop bypass
• Integrated messaging: e-mail, v-mail, fax mail
• Interoperability with NetMeeting, etc.
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
V.70
Terminal
H.324
Terminal
ISDN
Speech
Terminal
H.320
Terminal
Speech
Terminal
H.323 Terminal Characteristics
System Control
and
User Interface
Video
I/O
Equipment
Audio
I/O
Equipment
Video Codec
H.261, H263
Audio Codec
G.711, G.722,
G.723, G.723.1,
G.728, G.729
User Data
Applications
T.120
System Control
H.245
Control
Call Control
H.225.0
RAS Control
H.225.0
Receive Path
Delay
H.225.0 Layer
LAN Stack
Scope
of
H.323
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
Public VoIP Service
Using Packet Gateways
ISP “A”
Settlement Provider
Local
PSTN
(Trusted 3rd Party)
Authentication, Call
Routing, Billing and
Settlement Server
V
QoS
Interconnect
(or Internet)
POP (i)
ISP “A”
Backbone
V
POP (ii)
Local
PSTN
ISP “B”
ISP “B”
Backbone
Local
PSTN
V
VoIP Packet Gateway Roadmap
G.729, Group 3 Fax, RTP, RSVP
Enterprise
QoS
WAN
3600
Today
IP over Frame Relay, Leased Lines,
ISDN or other WAN links
V
V
3600
PSTN
Analog
Voice Interfaces
Trials
Q1’98
QoS
WAN
3600
V
V
Digital (T1/E1/PRI)
Voice Interfaces
Digital (BRI)
Voice Interfaces
Service Provider
Trials
Q1’98
I-Phone
POTS Phone
Residential
Residential
PSTN
Internet
V
H.323
Interoperability
Internet
Service
Provider
H.323 Interoperability
- H.323 VoIP Local Loop Bypass
- Resendential and business services
- Interoperability with NetMeeting type programs
Business
PBX
PSTN
PBX
I-Phone
H.323 S/W
V
Router
+ VoIP
Local
PSTN
I-Phone
H.323 S/W
QoS
WAN
POP
Internet
Residential
xDSL
I-Phone
H.323 S/W
Residential
XDSL
Modem
2nd line
phone
DSLA
M
Local
PSTN
V
Central Office
VoIP
Voice
Compression
VAD etc.
PCM CODER
G.711
64Kbps
FXS Voice
Card
G.729r8
8Kbps
Quality Policies
Packetizazion
Quality/Class of Service
RTP Header Compression
Plus Quality
Standard
Best Effort
G.729r8
8Kbps
Weighted
Fair Queuing,
IP Precedence
RSVP, ecc.
IP WAN
Link
FXS Voice
Card
Voice Integration
Small PBX,
POTS
2 Analog
Fax
QoS
WAN
QoS
WAN
QoS
WAN
PBX
V
Cisco
3600
Remote Branch
Plus Quality
Standard
Best Effort
PSTN
Central
Headquarter
Jitter - Delay Variation
Sender
Receiver
Network
B
A
C
Sender Transmits
t
A
D1
B
D2 = D1
C
Sink Receives
D3 = D2
t
• RTP timestamp for jitter estimation
• Adaptive jitter buffers in end points
Line Protocol Problem
Voice Packet
FTP Session
Time to :
• High Priority Queue Empty
• The Router starts sending
packet from another queue
1500 bytes take
187ms at 64K
Jumbogram FTP Session
Link IP
WAN
Line Protocol Problem
Voice Packet
FTP Session
Time t1 :
• New RTP Packets Come
• It has to wait the FTP
Jumbogram to be sent
1500 bytes take
187ms at 64K
VoIP
Link IP
WAN
Jumbogram FTP Session
Multilink PPP Interleave
Voice Packet
FTP Session
Time to :
• High Priority Queue Empty
• The Router starts sending
packet fragments from
another queue
FTP
FTP
Link IP
WAN
FTP
Multilink PPP Interleave
Voice Packet
FTP Session
Time t1 :
• New RTP Packets Come
• They are INTERLEAVED
between FTP fragments
“ INTERLEAVED ”
VoIP
FTP
Link IP
WAN
VoIP
FTP
Algorithm
VoIP
FTP
VoIP
FTP
Jumbogram FTP Session
VoIP
FTP
VoIP
FTP
• Fragment large packets
• Let small packets:
Use normal encapsulation
Interleave with fragmented traffic
RTP Compression
G.729r8
8Kbps
20ms
20 bytes IP Payload
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
20bytes
Payload
20 bytes IP Header
40bytes Header
RTP Compression
G.729r8
8Kbps
20ms
40bytes Header
20 bytes IP Payload
12 bytes RTP 8 bytes UDP
20 bytes IP Header
Real Time Protocol
Header Compression
20 bytes IP Payload
23-25 bytes
20msec
3-5 bytes
9,2Kbps
Network Architecture
Access
POP
Backbone
POP
Edge Functions
POP
Solutions require
cooperative edge and
backbone functions.
POP
Backbone Functions
Customer access aggregation
High speed transport
Policy Application
Security
Packet classification
Admission Control
Queuing
Congestion management
Services & traffic metering
Queue management
Policy enforcement
Traffic management
Packet Classification
Policy
Specification
Network Edge
Packet Classifier
Backbone
Layer 3
CAR Filter
Customer Premise
RSVP
Multimedia
•Up to 6 Traffic Classes via TOS bits
•Classification by Port, IP Address,
or Application Port
•Network or Customer Assignment
Mission-Critical
Per Application CAR
Drop
3rd
2nd
2nd
1st
CAR Policy Examples
Drop
1st
1st
2nd
CAR + Premium
Firm CAR
Drop
RSVP
Multimedia
Drop
3rd
2nd
2nd
1st
2nd
Mission-Critical
1st
CAR & Best Effort
Per Application CAR
The Problem of Congestion
Throughput
Managed Congestion
Uncontrolled Congestion
Offered Load
Congestion Management Goals
•Max Goodput and Min. Delay
•Scale to High Speed Nets
•Fairness
•Accommodates IP Burstiness
•Preserves Traffic Classes
•Avoids Global Synchronization
Number of Packets Discarded
WRED Service Profile Example
Two service levels
are shown; up to 6
can be defined.
Standard
Service
Profile
“Slope” is adjustable
Queue Length
Std Min.
Premium
Min.
Premium
Service
Profile
Std Max
Premium
Max
Putting it All Together
Solutions require
cooperative edge and
backbone functions
Access
High
Standard
Low
Core
L3 CAR
Ingress rate
thresholds.
L3 CAR
WRED/WFQ
Determine
packet class
Administer
packet class
Egressrate
thresholds
Multimedia Conference Manager
Gatekeeper
Proxy
•
Zone definition
•
Supported ASR interfaces
•
Bandwidth management
•
QoS
•
Authentication
•
Limit H.323 traffic on the WAN
•
Making calls with in a zone
•
Security
•
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
H.323 Infrastructure
Gatekeeper
Client H.323
Client H.323
Corp LAN
Router
Gateway
Proxy
Gatekeeper
H.320
(Over ISDN)
Internet
Real-time
Network
Telephone
Network
H.324
(Over POTs)
Speech Only
(Telephone)
H.323
H.323 Signaling
Admission Request
RAS
H.323
Admission Confirm
Gatekeeper
Setup
Q.931
Connect
H.323
Capabilities Exchange
Open Logical Channel
H.245
Open Logical Channel Acknowledge
RTP Stream
RTP Stream
RTCP Stream
Media