Transcript EP TIPHON - ETSI Portal

ETSI Workshop on
Quality Issues for IP Telephony
ETSI
TIPHON
overview of QoS activities
PROJECT
Mike Buckley
Lucent Technologies, UK
ETSI Workshop on Quality Issues for IP Telephony
8-9 June 1999, Sophia Antipolis, France
TIPHON WP5 QoS Activities
 Investigate General aspects of QoS in
TIPHON IP and hybrid SCN/IP Networks for
all TIPHON scenarios.
 Define End-to-end QoS Requirements for
conversational speech communications
over TIPHON networks.
 Investigate and define mechanisms for
Controlling End-to-end QoS in TIPHON
sytems.
 Define a model for QoS conformance
testing.
ETSI Workshop on Quality Issues for IP Telephony
8-9 June 1999, Sophia Antipolis, France
End-to-end QoS
TIPHON Classes
ETSI Workshop on Quality Issues for IP Telephony
8-9 June 1999, Sophia Antipolis, France
Definition of QoS Classes
Approach
 QoS is defined as mouth to ear as
perceived by the user,
 End-to-end QoS is defined by a number of
quality parameters,
 Four classes are defined for each quality
parameter.
 Three of the classes are guaranteed quality
(statistically) and the fourth is unguaranteed
(best efforts).
ETSI Workshop on Quality Issues for IP Telephony
8-9 June 1999, Sophia Antipolis, France
Definition of QoS Classes
Classes
 BEST: Better than todays PSTN,
 HIGH: Equivalent to todays PSTN,
 MEDIUM: Equivalent to todays wireless
networks,
 LOW: Significantly impaired but usable.
ETSI Workshop on Quality Issues for IP Telephony
8-9 June 1999, Sophia Antipolis, France
Definition of QoS Parameters
QoS Parameters
 Listening Speech Quality (one-way, non
conversational),
 End-to-end delay,
 Overall Transmission Quality Rating (R),
 Call Set-Up Time.
ETSI Workshop on Quality Issues for IP Telephony
8-9 June 1999, Sophia Antipolis, France
TIPHON QoS Classes
Listening Speech Quality
Class
Listening
Speech Quality
(one way, non
conversational)
4 (Best)
Better than
G.711
ETSI Workshop on Quality Issues for IP Telephony
8-9 June 1999, Sophia Antipolis, France
3 (High)
2 (Medium)
1 (Low)
Equivalent or
better than
G.726 at 32
kbit/s
Equivalent or
better than
GSM-FR
Undefined
TIPHON QoS Classes
End-to-end Delay
Class
End-to-end
Delay
4 (Best)
< 150ms
3 (High)
< 250ms
2 (Medium)
< 350ms
* Target
Reference:
ETSI Workshop on Quality Issues for IP Telephony
8-9 June 1999, Sophia Antipolis, France
G.114 One-way Transmission Time
1 (Low)
< 450ms*
TIPHON QoS Classes
Overall Transmission Quality Rating (R)
Class
Overall
Transmission
Quality Rating
(R )
4 (Best)
> 90
3 (High)
2 (Medium)
1 (Low)
> 80
> 70
> 60*
* Target
Reference:
G.107 The E-model, a computational model for use in transmission planning
ETSI Workshop on Quality Issues for IP Telephony
8-9 June 1999, Sophia Antipolis, France
TIPHON WP5 Next Steps
Next Steps
 Conformance Testing
 Network Planning Guidelines
 Definition of QoS Signalling Parameters
 Guidance for Implementers
ETSI Workshop on Quality Issues for IP Telephony
8-9 June 1999, Sophia Antipolis, France
Echo Control
 Two types of echo, acoustic echo in
terminals and echo in the SCN due to twofour-wire conversion,
 Assume echoes arising in terminals are
cancelled in terminal and echoes in SCN
within SCN or at IP/SCN gateway,
 Assume echoes in TIPHON systems are
suppressed to low enough levels that they
do not impair QoS.
ETSI Workshop on Quality Issues for IP Telephony
8-9 June 1999, Sophia Antipolis, France
Conformance Testing - Future Work
Conformance Testing
 Consider how the TIPHON QoS model can
be used to define TIPHON QoS
conformance tests,
 Define clear measurement techniques and
measurement resolution,
 Investigate the necessity of further tests,
such as echo return loss (ERL), to ensure
all aspects of the TIPHON QoS framework
are met by a system.
ETSI Workshop on Quality Issues for IP Telephony
8-9 June 1999, Sophia Antipolis, France
Planning Guidelines - Future Work
Planning Guidelines
 Define / describe planning guidelines for
TIPHON networks (Probably E-model
based),
 Investigate the possibly of extending current
techniques to cater for the unique nature of
VoIP,
 Provide guidance on TIPHON
interconnection to other networks.
ETSI Workshop on Quality Issues for IP Telephony
8-9 June 1999, Sophia Antipolis, France
QoS Signalling - Future Work
QoS Signalling
 Define a set of parameters that can be
exchanged between terminals/gateways
and the network and between network
domains that will enable end to end QoS
levels to be negotiated between users and
service providers,
 Define how the QoS budgets relate to the
defined parameters,
ETSI Workshop on Quality Issues for IP Telephony
8-9 June 1999, Sophia Antipolis, France
Guidance for Implementers - Future Work
Guidance for Implementers
 Provide guidance to network operators,
network equipment manufacturers and
terminal manufacturers on design criteria for
achieving network and terminal
performance parameters,
 Where appropriate specify default values for
terminal and network equipment parameters
that directly influence performance,
 Investigate reference designs and
configurations to be used for testing
purposes.
ETSI Workshop on Quality Issues for IP Telephony
8-9 June 1999, Sophia Antipolis, France
Establishing & Guaranteeing
QoS Class across Multiple
Administrative Domains
ETSI Workshop on Quality Issues for IP Telephony
8-9 June 1999, Sophia Antipolis, France
The Concept of QoS Budgets
ETSI Workshop on Quality Issues for IP Telephony
8-9 June 1999, Sophia Antipolis, France
QoS Architecture
ETSI Workshop on Quality Issues for IP Telephony
8-9 June 1999, Sophia Antipolis, France
Components of a QoS Architecture
QoS aware service elements
 Gatekeepers (H.323) or other service
managers negociate with the service element
in terminals/gateways and with their peers,
 exchange information with the management
layer, to establish the QoS budgets within their
domain
ETSI Workshop on Quality Issues for IP Telephony
8-9 June 1999, Sophia Antipolis, France
QoS Architecture
ETSI Workshop on Quality Issues for IP Telephony
8-9 June 1999, Sophia Antipolis, France
Components of a QoS Architecture
Management network
 Controls resources in the transport network
to deliver a given grade of service for
packets traversing the transport network.
 Operates with the service layer, monitoring
and controlling resource within the transport
network, and providing resource related
information to the service layer.
ETSI Workshop on Quality Issues for IP Telephony
8-9 June 1999, Sophia Antipolis, France
QoS Architecture
ETSI Workshop on Quality Issues for IP Telephony
8-9 June 1999, Sophia Antipolis, France
Components of a QoS Architecture
QoS aware transport network
 Within this layer, end-to-end delay, delay
jitter, packet loss and bandwidth must be
controlled to achieve a guaranteed grade of
service for packets traversing the network.
 Possible mechanisms Diffserv, RSVP,
MPLS.
ETSI Workshop on Quality Issues for IP Telephony
8-9 June 1999, Sophia Antipolis, France
Proposal for a QoS Control Mechanism
Assumptions
 In each network domain through which the
call flows there will be (at least) one
gatekeeper or service element responsible
for the call.
 each gatekeeper has access to the network
management system which can control
bandwidth, end-to-end delay, delay jitter and
packet loss within its domain.
ETSI Workshop on Quality Issues for IP Telephony
8-9 June 1999, Sophia Antipolis, France
Proposal for a QoS Control Mechanism
Approach
 Signalling takes place between calling
terminal/gateway and access gatekeeper
and between gatekeepers at call set-up to
negotiate the end-to-end QoS required for
that call.
 each gatekeeper signals to the network
management system within its domain the
required QoS parameters.
 media packets are marked by the ingress
router (or gateway) to indicate the
negotiated service class.
ETSI Workshop on Quality Issues for IP Telephony
8-9 June 1999, Sophia Antipolis, France
Proposal for a QoS Negotiation
Mechanism
 The approach to the problem is domain to domain.
 Either the user signals the desired QoS class to
the access gatekeeper or this class is attached to
the user's subscription; either way the access
gatekeeper knows the desired QoS class for the
call.
 The first gatekeeper ascertains the required
budget for the call within its network domain.
 The access gatekeeper deduces the budget left for
all remaining stages through which the call will
pass and communicates this to the next network
domain.
ETSI Workshop on Quality Issues for IP Telephony
8-9 June 1999, Sophia Antipolis, France
Proposal for a QoS Negotiation
Mechanism
 The gatekeeper in the next domain then
ascertains its required budget, and signals
the budget remaining to the next domain.
 This process continues until the egress
gatekeeper is reached.
 The egress gatekeeper then signals
confirmation back up the chain of
gatekeepers that the requested QoS class
can be delivered or that a lower grade of
service must be offered.
ETSI Workshop on Quality Issues for IP Telephony
8-9 June 1999, Sophia Antipolis, France
Approach to QoS Negotiation
DelayBudget=
100ms
DelayBudget=
160ms
DelayBudget=
200ms
DelayBudget=
80ms
Network
Dom ain 2
Network
Dom ain 1
Initiating Terminal
ETSI Workshop on Quality Issues for IP Telephony
8-9 June 1999, Sophia Antipolis, France
Network
Dom ain 3
Receiving Terminal
Proposal for a QoS Negotiation
Mechanism
Other Considerations
 The access gatekeeper must have
information on the quality of the link to the
terminal and the terminal class (and hence
a priori knowledge of the budget consumed
by the terminal and access network).
 This egress gatekeeper like the first must
have a priori knowledge of the budget
consumed by the terminating terminal and
its access network.
ETSI Workshop on Quality Issues for IP Telephony
8-9 June 1999, Sophia Antipolis, France
Proposal for a QoS Control Mechanism
Implications
 The transport network must be capable of
guaranteeing bandwidth allocation, packet
loss, end to end delay and delay jitter within
its domain.
 Media packets will be marked with the QoS
class negotiated. Three quaranteed classes
and one unguaranteed.
 Service management elements must have
knowledge of the transport network domains
through which the call passes
ETSI Workshop on Quality Issues for IP Telephony
8-9 June 1999, Sophia Antipolis, France
Proposal for a QoS Control Mechanism
Next Steps
 Define parameters to be exchanged
between sevice layer elements in
negotiating QoS class .
 Specify extensions to existing call set-up
protocols to convey these parameters. e.g.
H.225, H.245.
 Management layer and transport layer
implications.
ETSI Workshop on Quality Issues for IP Telephony
8-9 June 1999, Sophia Antipolis, France
Further Information
http://www.etsi.fr/tiphon/
Web site
ftp access to documentation
WG5 mailing-list
ETSI Workshop on Quality Issues for IP Telephony
8-9 June 1999, Sophia Antipolis, France
TIPHON QoS Documentation
TR 101 329 v1.3.0
TIPHON; General aspects of Quality of Service
DTR/TIPHON-5003 v0.0.0
A signalling system to support TIPHON Quality of Service
ETSI Workshop on Quality Issues for IP Telephony
8-9 June 1999, Sophia Antipolis, France