International Telecommunication Union
Signalling
Requirements for Endto-End IP QoS
Martin Dolly /Al Morton
AT&T
Workshop on End-to-End Quality of Service.What is it? How do we get it?
Geneva, 1-3 October 2003
ITU-T
Scope of Signalling
Requirements for End-to-End
IP QoS
o
o
1-3 October 2003
Define requirements and the
signalling information elements that
will enable the development of a
signalling protocol(s) capable of the
request, negotiation and ultimately
delivery of known IP QoS classes UNI
to UNI, spanning NNIs as required
Requirements also address signaling
information related to traffic
priority and admission control
Workshop on End-to-End Quality of Service. What is it? How do we get it?
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Scope Continued
ITU-T o To meet the QoS classes of Y.1541, a
network provider needs to implement
services such as those specified in
Y.1221
o To implement the transfer capabilities
defined in Y.1221, a network needs to
provide specific user plane functionality
at UNI, NNI, INI interfaces
o A network may be provisioned, statically
or dynamically on a per call basis, to
meet the performance requirements of
Y.1541
1-3 October 2003
Workshop on End-to-End Quality of Service. What is it? How do we get it?
3
Scope of QoS Signalling Reqts.
ITU-T
1-3 October 2003
Workshop on End-to-End Quality of Service. What is it? How do we get it?
4
ITU-T
Functional Entities Within the
Network (Assumed)
o Subscription Verification
o Authentication
o Call Admission Control
o Performance Management
UNI
NNI
GW
GW
Network
1-3 October 2003
Workshop on End-to-End Quality of Service. What is it? How do we get it?
5
Service Level Parameters
o QoS class from Y.1541
ITU-T
• Numerical Objectives for IP Loss Ratio, IP
Transfer Delay, and IP Delay Variation may
be indicated by specifying the QoS class
from Y.1541 as a signalling parameter
o Traffic Parameters from Y.1221
• Peak rate (Rp)
• Peak bucket size (Bp)
• Sustainable rate (Rs)
• Sustainable bucket size (Bs)
• Maximum allowed packet size (M)
o IP DSCP as specified in RFC 2474
1-3 October 2003
Workshop on End-to-End Quality of Service. What is it? How do we get it?
6
Attributes of QoS Signalling
Request
ITU-T
o Network QoS Class (i.e. Y.1541/Tbl. 1)
o Network capacity required, at both
the application and network (I.e.,
Y.1221) levels
o (future) Reliability/Priority Class with
which the service is to be sustained
o Optional Attributes:
• Application type
• Quality Category per Application type
1-3 October 2003
Workshop on End-to-End Quality of Service. What is it? How do we get it?
7
Attributes of Network Response
to
User
QoS
Requests
ITU-T
o An Identification Code for the request
exchange, to be used in this response
and all messages that follow (such as
User ACK, or Release, and also in
Network-Network messages). When used
together with other information, such as
Src address, each request can be
uniquely referenced.
o The simple acknowledgement and
acceptance of user/TE requests.
1-3 October 2003
Workshop on End-to-End Quality of Service. What is it? How do we get it?
8
Attributes of Network Response
to
User
QoS
Requests
ITU-T
o The expected performance level
1-3 October 2003
(optional).
o The ability to achieve a performance level
that is better than an aspect of the QoS
Class response, (optional).
o The ability to reject a request and, at the
same time, to offer a modified service
level that can be met. The response may
modify the request and may include
commitments to an alternate QoS Class, a
lower capacity, and other indications such
as performance level estimates.
Workshop on End-to-End Quality of Service. What is it? How do we get it?
9
Other Signalling Requirements
ITU-T
o Flow Control for user QoS requests and
o
o
o
o
o
1-3 October 2003
re-requests
Performance requirements for Network
QoS requests and re-requests
Contention resolution
Forward and backward compatibility
User-Initiated QoS Resource
Modifications
Reliability/Priority attributes including
Emergency Services
Workshop on End-to-End Quality of Service. What is it? How do we get it?
10
Architecture for IP Signalling
ITU-T
User
Application Request
& QoS
Requirements Result
Terminal Equip
Application Request
Requirements
Cnfg.Choices
Network
QoS Classes
& Decisions
ACK/REJ/Mod
NNI
Network(s)
Request
ACK/REJ/Mod
Design/Eng.
Feedback
Provisioning
QoS Mech.
Monitoring
Reports
(SLAs)
Perceived
QoS
1-3 October 2003
UNI
Workshop on End-to-End Quality of Service. What is it? How do we get it?
11
ITU-T
1-3 October 2003
Control Plane and Data Plane
Mechanisms: Relationship
Workshop on End-to-End Quality of Service. What is it? How do we get it?
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Signalling Flows
ITU-T
o Request – Ack/Accepted
UNI
TEo
Network A
REQ
NNI
Network B
REQ
TEd
REQ
ACK
ACK
ACK
UNI
OR
REQ
REQ
REQ
ACK
ACK
ACK
OR
REQ
ACK
1-3 October 2003
REQ
REQ
ACK
ACK
Workshop on End-to-End Quality of Service. What is it? How do we get it?
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Signalling Flows
ITU-T o BW or Class Modification
UNI
TEo
Network A
NNI
Network B
UNI
TEd
REQo1
MODo2
ACCo2
REQo2
ACK
REQo2
ACK
ACK
OR
REQo1
REQo1
MODo2
MODo2
ACCo2
ACCo2
ACK
1-3 October 2003
REQo2
ACK
ACK
Workshop on End-to-End Quality of Service. What is it? How do we get it?
14
Summary/Next Steps
ITU-T
1-3 October 2003
o Look to match initial requirements
with on-going protocol spec. efforts
o Define requirements and signalling
information elements that support a
Y.1221 “Traffic Contract”, including
Y.1541 QoS Classes, for NNI and UNI
signalling protocol(s)
o Enhance definition of the functional
entities within each Network
o Consider Additional Signalling flows
for errors, policy rejection, etc.
Workshop on End-to-End Quality of Service. What is it? How do we get it?
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