Transcript Recommendation Y.1541 QoS Classes: A Basis for IP Network QoS

T1A1/2002-066
QoS Signaling for IP-Based Multi-Service Networks:
Motivation, Requirements, and Proposed Actions
Joint T1A1/T1S1 Meeting
October 2, 2002
Ottawa, Ontario
Neal Seitz
Vice Chair, T1A1
[email protected]
Adapted from material presented at the ATIS-sponsored Summit
on Signaling for Voice over Internet Protocol, August 13-14, 2002
QoS Control: Key to Deployment
of Multi-Service IP-Based Networks
Outline
•
Context -- Importance of QoS Control
•
Getting There -- Role of Y.1541 / Y.1221
•
Example QoS Signaling Exchange
•
Other Relevant International Standards Activities
•
Proposed T1A1/T1S1 Standards Actions
 Y.1541 QoS Classes and Y.1221 Traffic Contracts
should be specified in IP QoS signaling protocols
Problem Context
Pr(e/o)mise of IP/PSTN Convergence
•
Cost savings through technology consolidation
•
Industry growth through service innovation
QoS Signaling: The Nexus and Gordian Knot
•
Convergence presupposes toll quality voice on a
multi-service, multi-provider IP infrastructure
•
Toll quality voice requires service differentiation
and resource control,  QoS (and flow) signaling
 Signaling QoS (and flow) parameters will be
essential to successful IP/PSTN convergence
Importance of IP QoS Signaling
VoIP/MM needs are clear, but too demanding for today’s IP
• Rec. G.114 -- End-to-end signal transmission time
• Rec. G.109 -- Categories of speech transmission quality
• Rec. G.107 -- Computation for transmission planning
IP QoS solutions exist, but are not widely implemented
• RSVP/intserv -- Controlled load, guaranteed services
• DIFFSERV -- EF, AF per hop behaviors (PHBs)
• MPLS, GMPLS -- Traffic engineering, CoS, QoS, VPNs
 IP QoS signaling is the practical means of relating
user application needs with network QoS solutions
Rec. Y.1541: Quantifying User
QoS Needs in IP Terms
Relate subjective descriptions of QoS imperfections …
• Audio: “staticky, warbley, muffled, clipped”
• Video: “blurry, jerky, blocky, busy, blotchy”
With measurable IP network/terminal characteristics …
• Packet transfer delay, delay variation
• Packet loss and error ratios
 Capture results in a limited set of QoS classes …
–
–
–
Categorize the major IP user application needs
Can be communicated among networks via signaling
Can be implemented with existing IP QoS mechanisms
Y.1541 “Mapping” Function




Voice
Video
Data
Call Control




Customer-Perceived QoS
 Subjective Descriptors
 Objective Estimators
Voice
Video
Data
Call Control
NI to NI QoS (Y.1541)
 Speed, Accuracy, Dependability
 Service Availability (Future)
NI
NI
Terminal
Terminal
Network QoS
Control
Network
Bearer
Network
Network QoS
Control
Network
Bearer
Network
Network QoS
Control
Network
Bearer
Network
Table 1/Y.1541 -- IP QoS Class
Definitions and NP Objectives
Network
Performance
Parameter
IPTD
IPDV
IPLR
IPER
Nature of
Network
Performance
Objective
Upper bound
on the mean
IPTD
Upper bound
on the 1-10-3
quantile of
IPTD minus
the minimum
IPTD
Upper bound
on the packet
loss
probability
Upper bound
Class 0
100 ms
Class 1
400 ms
Class 2
100 ms
Class 3
400 ms
Class 4
1s
Class 5
(Unspecified)
U
50 ms
50 ms
U
U
U
U
1*10-3
1*10-3
1*10-3
1*10-3
1*10-3
U
1*10-4
U
Table 1/Y.1541 -- IP QoS Class
Definitions and NP Objectives
Network
Performance
Parameter
IPTD
IPDV
IPLR
IPER
Nature of
Network
Performance
Objective
Upper bound
on the mean
IPTD
Upper bound
on the 1-10-3
quantile of
IPTD minus
the minimum
IPTD
Upper bound
on the packet
loss
probability
Upper bound
Class 0
100 ms
Class 1
400 ms
Class 2
100 ms
Class 3
400 ms
Class 4
1s
Class 5
(Unspecified)
U
50 ms
50 ms
U
U
U
U
1*10-3
1*10-3
1*10-3
1*10-3
1*10-3
U
1*10-4
U
Table 1/Y.1541 -- IP QoS Class
Definitions and NP Objectives
Network
Performance
Parameter
IPTD
IPDV
IPLR
IPER
Nature of
Network
Performance
Objective
Upper bound
on the mean
IPTD
Upper bound
on the 1-10-3
quantile of
IPTD minus
the minimum
IPTD
Upper bound
on the packet
loss
probability
Upper bound
Class 0
100 ms
Class 1
400 ms
Class 2
100 ms
Class 3
400 ms
Class 4
1s
Class 5
(Unspecified)
U
50 ms
50 ms
U
U
U
U
1*10-3
1*10-3
1*10-3
1*10-3
1*10-3
U
1*10-4
U
Table 2/Y.1541
Guidance for IP QoS Classes
QoS
Class
Applications (Examples)
1
Real-Time, Jitter Sensitive,
High Interaction
(VoIP, VTC)
Real-Time, Jitter Sensitive,
Interactive (VoIP, VTC)
2
Transaction Data, Highly
Interactive (Signalling)
0
3
4
5
Transaction Data,
Interactive
Low Loss Only (Short
Transactions, Bulk Data,
Video Streaming)
Traditional Applications of
Default IP Networks
Node Mechanisms
Separate Queue with
Preferential Servicing,
Traffic Grooming
Separate Queue,
Drop Priority
Network Techniques
Constrained Routing and
Distance
Less Constrained Routing
and Distance
Constratined Routing and
Distance
Less Constratinged
Routing and Distance
Long Queue,
Drop Priority
Any Route/Path
Separate Queue
(Lowest Priority)
Any Route/Path
Attributes of the Y.1541
IP Network QoS Classes
•
•
•
•
Encompass the major IP user application categories
Are relatable to practical IP network QoS mechanisms
Can be achieved in realistic network implementations
Are verifiable at jurisdictional network boundaries
(TE/IWF can measure QoS to ensure values are met)
• Can support QoS negotiation among networks
 Meet the need for a lingua franca to support
QoS interworking
Y.1221: Traffic and Congestion
Control in IP Based Networks
Traffic Contract
IP Transfer Capability
QoS Class
Traffic Descriptor
• Dedicated BW
• Statistical BW
• Best Effort
(Y.1541)
• Max Pkt Size
• Token Bucket
– Rate (Rp, Rs)
– Size (Bp, Bs)
 Y.1221 Traffic Contract complements Y.1541 QoS
Class by describing flow characteristics and limits
Signaling QoS and Flow Requests:
Requirements Proposed by SG 13
•
•
•
•
•
•
•
•
Allow the user requesting service to specify QoS class
Allow specification of traffic descriptor (Rec. Y.1221)
Allow well-defined apps to be identified ex(im)plicitly
Support requests for basic IP transport: QoS, traffic
Let user decide whether to take lower QoS or clear call
Implement dynamic QoS control, not static allocation
Support QoS class mapping among diverse networks
Allow QoS choices for call control, availability (future)
 Signal
Y.1541, Y.1221 QoS / flow values explicitly
Example QoS Signaling Exchange
Customer Service
Request, Including
Call Characteristics
Customer Service
Notification, Including
Call Characteristics
Translation of
Service RQ to
Y.1541/Y.1221
QoS/Flow RQ
Translation of
Y.1541/Y.1221
QoS/Flow RQ
to Service RQ
Terminal
Terminal
Signaling Message
(with QoS/Flow RQ)
Control
Network
Bearer
Network
Control
Network
Bearer
Network
Control
Network
Bearer
Network
Example QoS Signaling Exchange
Customer Service
Confirmation, Including
Call Characteristics
Service Response,
Possibly Including New
Call Characteristics
Translation of
Y.1541/Y.1221
QoS/Flow RSP
to Service RSP
Terminal
Translation of
Service RSP to
Y.1541/Y.1221
QoS/Flow RSP
Signaling Message
(with QoS/Flow RSP)
Control
Network
Bearer
Network
Control
Network
Bearer
Network
Control
Network
Bearer
Network
Terminal
QoS Signaling Completed
-- Flow Established
Customer Data
Customer Data
Terminal
Terminal
(QoS and flow characteristics
consistent with Y.1541, Y.1221)
Control
Network
Bearer
Network
Control
Network
Bearer
Network
Control
Network
Bearer
Network
Other Relevant Activities: IETF IPPM
Topic
ITU-T Recs
IETF RFCs
Framework
I.350, Y.1540
2330
Loss
Y.1540
2680
Delay
Y.1540
2679 (One Way)
2681 (Round Trip)
Delay Var.
Y.1540
(I-D on IPDV)
Availability
Y.1540
2678
Sampling
Y.1540 (Availability)
2330
(I-D on Periodic Streams)
Other Relevant Activities:
ETSI TS 101-329-2
TIPHON Speech QoS Classes
• Wideband -- “Better than PSTN”
• Narrowband -- “Similar to PSTN”
– High, Medium, Acceptable
• Best Effort -- “No guarantees of performance”
Limitations -- Applicable Only to IP Telephony
• Do not address data, video, multimedia IP applications
• Do not support requests for basic IP packet transport
 TIPHON classes alone are insufficient to signal user
QoS requirements in multi-service IP based networks
Other Relevant Activities: SG 16 (H.qos.arch)
H.323 Annex
N
Service
Domain 1
Application Level QoS
Signalling
H.323 Annex N
Service
Domain 1
Application Plane
Vertical QoS
Signalling
(H.trans.cont)
Transport Plane
Transport
Domain 1
Transport
Domain 3
Transport
Domain 2
Packet Flow
QoS Signalling
Call Signalling
Transport Level QoS
Signalling
(H.trans.cont or NSIS)
Adapted From: IP Cablecom & MEDIACOM 2004 Workshop, 12 - 15 March 2002 Geneva
H.323 Annex
N
Liaison from SG 11 to SGs 12 and 13 on
Generic End-to-End QoS Service Requirements
(March, 2002)
• “We would like to receive guidance from SG 12 what set of QoS
service classes should be used. Based on ITU-T Recommendation
G.1010 and the intentions of SG16 for H.mmclass we assume the
ETSI TIPHON defined speech QoS service classes for VoIP.”
• “We would like to receive guidance from SG 13 to which specific
QoS classes in IP and ATM the QoS services classes in BICC
networks (and potentially other networks like SIP and H.323)
need to be mapped for the existing PSTN/ISDN/PLMN services.”
 T1A1/T1S1 should address these issues, develop
U.S. views/proposals for input to SGs 12, 13, and 11
SG 11 Proposed Framework for End-to-End
QoS Service Control and Network QoS Control
1) BICC, SIP, H.323
CSF
(TIPHON)
End-to-end QoS
service control
(TIPHON)
End-to-end QoS
service control
2) CBC,
H.248/MEGACO
CSF
(TIPHON)
QoS service control
(TIPHON)
End-to-end QoS
service control
(TIPHON)
QoS service control
2) CBC,
H.248/MEGACO
3) IP BCP
(SG13) IPQoS/IPTC
BIWF
4) DiffServ, RSVP, MPLS
(SG13) IPQoS/IPTC

IP network
supporting
IPQoS/IPTC
BIWF
4) DiffServ, RSVP, MPLS
(SG13) IPQoS/IPTC
SG 11 should address all IP applications (not just
voice) in defining QoS service control protocols
Business Realities and Standards Impacts
Feedback from the VoIP Summit
• IP does not prove in end to end as a replacement for
the PSTN in providing voice telephone service
• The payoff is in combining voice with data, video, and
other applications in a multi-service IP network
QoS Signaling Implications
• Signaling QoS classes that address only VoIP will not
be fruitful, and should not be recommended by ITU-T
• Comprehensive, multi-service QoS values must be
specified in IP network QoS signaling protocols
 T1A1/T1S1 should recommend Y.1541/Y.1221
to ITU-T as basis for IP network QoS signaling
Upcoming ITU-T Meetings, Proposed Actions
SG 13 (Nov. 2002): Address SG 11 Liaison Response
 Existing TIPHON voice QoS classes do not provide an adequate
basis for multi-service IP network QoS specification
SG 12 (January 2003): Address SG 11 Liaison Response
– Y.1541/Y.1221 values (plus codec specifications) should be
defined in SG 11 defined IP network QoS signaling protocols
SG 11 (Nov. 2002): Define QoS Signaling Requirements
– Architecture, QoS request attributes, signaling flows, examples
– Reference Y.1541/Y.1221 to define signalling message content
 Coordinated effort among ITU-T SGs warranted
Backup Slides
ETSI TR 101-329-2
Table 1: Overall transmission quality Rating (R) for TIPHON systems
3
(WIDEBAND)
Overall
Transmission
Quality
Rating (R)
(see note 2)
2 (NARROWBAND)
1
(BEST
EFFORT)
2H
(HIGH)
2M
(MEDIUM)
2A
(ACCEPTABLE)
> 80
> 70
> 50
> 50
(see note 3)
NOTE 1: The R-value incorporates all degradations, including the effects of packet loss.
NOTE 2: The R-value characterization of systems employing wideband codecs is under study.
NOTE 3: The rating for the best effort class is a target value.
(Overall transmission quality rating (R) describes the full acoustic-to-acoustic (mouth to ear) quality,
experienced by an average user, for a typical situation using a "standard" telephony handset.)
ETSI TR 101-329-2
Table 2: Categories of speech transmission quality as defined in ITU-T
Overall
Transmission
Quality
Rating
User's
Satisfaction
90 < R < 100
80 < R < 90
70 < R < 80
60 < R < 70
50 < R < 60
Very satisfied
Satisfied
Some users
dissatisfied
Many users
dissatisfied
Nearly all
users
dissatisfied
(The relation between overall transmission quality rating (R) and user perception of quality is defined in
ITU-T Recommendation G.109. Table 2 is extracted from that recommendation.)
ETSI TR 101-329-2
Table 3: Listener speech quality of TIPHON systems
3
(WIDEBAND)
2 (NARROWBAND)
2H
(HIGH)
2M
(MEDIUM)
2A
(ACCEPTABLE)
1
(BEST
EFFORT)
Relative
Speech Quality
(one way,
non interactive
speech quality)
Better than
G.711 [6]
Equivalent or
better than
ITU-T
Recommendation
G.726 at
32 kbit/s [7]
Equivalent
or better
than
GSM-FR
[1]
Not defined
Not
defined
Resultant
Overall
Transmission
Quality Rating
(R)
n.a.
> 86
> 73
> 50
> 50
NOTE 1: The R values above are derived from E-Model calculations assuming that perfect echo control is deployed, that there is zero delay through
the system, that standard terminals are used, also that all impairments related to low bit-rate coding - including the effects of packet loss - are taken into
account.
NOTE 2: "Relative speech quality" does not describe the Listener Speech Quality (the full acoustic-to-acoustic (mouth to ear) quality that will be
experienced by a user). This will be dependent on the acoustic quality of the individual TIPHON terminal as well as the quality of the TIPHON
network.
NOTE: The use of codec examples indicates a relative speech quality, not a recommended codec for implementation. The performance levels include
any degradation caused by network or terminal, such as packet loss.
ETSI TR 101-329-2
Table 4: End-to-end delay for TIPHON Systems
2 (NARROWBAND)
3
(WIDEBAND)
End-toend Delay
< 100 ms
1
(BEST
EFFORT)
2H
(HIGH)
2M
(MEDIUM)
2A
(ACCEPTABLE)
< 100 ms
< 150 ms
< 400 ms
NOTE: The delay for best effort class is a target value.
< 400 ms
Specification of QoS Parameters
-- Ongoing and Planned Work
WP 4/13
• Y.1540 Enhancements
– IPDV Definition(s)
– Bursty Packet Loss
– Service Availability
• Y.1541 Enhancements
– BC Quality Video QoS?
• Signaling Requirements
• Y.1530 (Call Processing)
• “Other” (e.g., MPLS, …)
IPPM
• RFCs Planned
– Loss Patterns
– Bulk Transfer Capacity
• I-Ds Received
– Packet Reordering
– Msmt Protocol Rqmts
– MIB
• Newly Chartered Work
– Link BW Capacity