Transcript End to End Quality of Service

SOURCE:
TSACC
TITLE:
End to end Quality of Service
AGENDA ITEM:
7.1..2
DECISION
GSC-8 015
X
DISCUSSION
INFORMATION
End to End Quality of
Service
Paul Coverdale
Nortel Networks
Tel: +1 613 763 4277
Email: [email protected]
14/04/2003
End to end QoS
• everybody talks about it
• what does it mean ?
1
• how do we get it ?
14/04/2003
GSC-8, OTTAWA
1
Bottom-up approach to end to end QoS
• lots of attention on mechanisms and protocols for
enabling QoS in individual IP domains
• these mechanisms drive resulting end to end QoS
• not clear on benefit to end-user
2
End to end QoS required by user (QoE)
QoS-enabled
Domain 1
14/04/2003
QoS-enabled
Domain 2
GSC-8, OTTAWA
QoS-enabled
Domain n
2
Top-down approach to end to end QoS
• focus on customer (the one who pays the bill)
• understand end-user expectations for QoS
• Quality of Experience (QoE)
• use these to drive requirements for specific QoS
mechanisms for individual domains
3
End to end QoS required by user (QoE)
QoS-enabled
Domain 1
14/04/2003
QoS-enabled
Domain 2
GSC-8, OTTAWA
QoS-enabled
Domain n
3
End-user requirements
• wide range of user requirements, depending on
application
Packet Loss
5%
Interactive
Responsive
Timely
Non-critical
4
Conversational
voice and video
0%
Zero
loss
100 msec
Command
/ control
(eg Telnet,
Interactive
games)
Voice/video
messaging
1 sec
Streaming
audio/video
10 sec
Transactions
(eg E-commerce,
Web-browsing, Email access)
Messaging,
Downloads
(eg FTP,
still image)
Delay
Fax
100 sec
Background
(eg Usenet)
From ITU-T Rec. G.1010
14/04/2003
GSC-8, OTTAWA
4
Network QoS Classes
• no need to try to meet specific QoS requirements for
each application
• provide several network QoS classes to carry traffic
having broadly similar requirements
QoS Classes
Network
Class 0
Performance
Parameter
Class 1
Class 2
Class 3
Class 4
5
Class 5
Unspecified
Transfer delay
100ms
400ms
100ms
400ms
1s
U
Delay variation
50ms
50ms
U
U
U
U
Packet loss ratio
1*10-3
1*10-3
1*10-3
1*10-3
1*10-3
U
Packet error ratio
1*10-4
U
From ITU-T Rec. Y.1541
14/04/2003
GSC-8, OTTAWA
5
Implementing end to end QoS
• two fundamentally different approaches
• Internet model
6
• Managed-Network model
14/04/2003
GSC-8, OTTAWA
6
Internet model
• intelligence remains at network edge
• provides autonomy for end-points
• but who is responsible for end to end QoS ?
Application
Plane
7
Transport Plane
Transport
Domain 1
Transport
Domain 2
Transport
Domain 3
Call Signalling
QoS Signalling
Bearer Traffic
14/04/2003
GSC-8, OTTAWA
7
Managed-Network model
• service provider able to control end to end QoS
• but end-point tied to specific service provider
Service
Domain 2
Service
Domain 1
8
Application Plane
Transport Plane
Transport
Domain 1
Call Signalling
Transport
Domain 3
Transport
Domain 2
QoS Signalling
Bearer Traffic
14/04/2003
GSC-8, OTTAWA
8
Standards Bodies addressing QoS
• many Standards Bodies involved in QoS
• IETF, ITU, ETSI, 3GPP, 3GPP2, IEEE, T1, MEF, etc
• main focus on QoS mechanisms or on specific
network elements (eg wireless or cable access)
• achieving complete end to end QoS is clearly a
Standards issue
• need for better co-operation and co-ordination
between Bodies to address end to end picture
9
14/04/2003
GSC-8, OTTAWA
9
Conclusions
• need for recognition and reconciliation of different
viewpoints on QoS
• need for focus on the end-user
• need for better coordination between Standards Bodies
• ITU-T is well-positioned to take the leadership role
• ITU-T Workshop on End to End QoS planned for Oct
1-3 2003
• Recommend GSC-8 should endorse a Resolution
proposing ITU-T as prime Body for establishing global
standards for end to end QoS
10
14/04/2003
GSC-8, OTTAWA
10