Neal Seitz Vice Chair, T1A1 Joint T1A1/T1S1 Meeting October 2, 2002 Ottawa, Ontario QoS Signaling for IP-Based Multi-Service Networks: Motivation, Requirements, and Proposed Actions Adapted from material presented at the ATIS-sponsored Summit on Signaling for Voice over Internet Protocol, August 13-14, 2002 T1A1/

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 End-to-end signal transmission time Rec. G Categories of speech transmission quality Rec. G 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

Terminal NI to NI QoS (Y.1541)  Speed, Accuracy, Dependability  Service Availability (Future) Y.1541 “Mapping” Function  Voice  Video  Data  Call Control Customer-Perceived QoS  Subjective Descriptors  Objective Estimators  Voice  Video  Data  Call Control Network QoS Control Network Control Network Bearer Network Bearer Network Bearer Network Control Network NI

Table 1/Y IP QoS Class Definitions and NP Objectives

Table 2/Y.1541 Guidance for IP QoS Classes

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  Y.1221 Traffic Contract complements Y.1541 QoS Class by describing flow characteristics and limits Traffic Contract Dedicated BW Statistical BW Best Effort Max Pkt Size Token Bucket –Rate (Rp, Rs) –Size (Bp, Bs) (Y.1541) IP Transfer CapabilityTraffic DescriptorQoS Class

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

Terminal Example QoS Signaling Exchange Customer Service Request, Including Call Characteristics Control Network Control Network Bearer Network Bearer Network Bearer Network Control Network Customer Service Notification, Including Call Characteristics Signaling Message (with QoS/Flow RQ) 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 Example QoS Signaling Exchange Customer Service Confirmation, Including Call Characteristics Control Network Control Network Bearer Network Bearer Network Bearer Network Control Network Service Response, Possibly Including New Call Characteristics Translation of Y.1541/Y.1221 QoS/Flow RSP to Service RSP Translation of Service RSP to Y.1541/Y.1221 QoS/Flow RSP Signaling Message (with QoS/Flow RSP)

Terminal QoS Signaling Completed -- Flow Established Control Network Control Network Bearer Network Bearer Network Bearer Network Control Network Customer Data (QoS and flow characteristics consistent with Y.1541, Y.1221)

Other Relevant Activities: IETF IPPM TopicITU-T RecsIETF RFCs FrameworkI.350, Y LossY DelayY (One Way) 2681 (Round Trip) Delay Var.Y.1540(I-D on IPDV) AvailabilityY SamplingY.1540 (Availability)2330 (I-D on Periodic Streams)

Other Relevant Activities: ETSI TS 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

Call Signalling Packet Flow QoS Signalling Application Plane Transport Plane Other Relevant Activities: SG 16 (H.qos.arch) Service Domain 1 Transport Domain 1 Transport Domain 2 Transport Domain 3 Service Domain 1 Application Level QoS Signalling H.323 Annex N Vertical QoS Signalling (H.trans.cont) Transport Level QoS Signalling (H.trans.cont or NSIS) H.323 Annex N Adapted From: IP Cablecom & MEDIACOM 2004 Workshop, March 2002 Geneva

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  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 (WIDEBAND) 2 (NARROWBAND)1 (BEST EFFORT) 2H (HIGH) 2M (MEDIUM) 2A (ACCEPTABLE) Overall Transmission Quality Rating (R) (see note 2) > 80> 70> 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. Table 1: Overall transmission quality Rating (R) for TIPHON systems (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 Overall Transmission Quality Rating 90 < R < < R < 9070 < R < 8060 < R < 7050 < R < 60 User's Satisfaction Very satisfiedSatisfiedSome users dissatisfied Many users dissatisfied Nearly all users dissatisfied Table 2: Categories of speech transmission quality as defined in ITU-T (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 (WIDEBAND) 2 (NARROWBAND) 1 (BEST EFFORT) 2H (HIGH) 2M (MEDIUM) 2A (ACCEPTABLE) 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 Resultant Overall Transmission Quality Rating (R) n.a.> 86> 73> 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. Table 3: Listener speech quality of TIPHON systems

ETSI TR (WIDEBAND) 2 (NARROWBAND) 1 (BEST EFFORT) 2H (HIGH) 2M (MEDIUM) 2A (ACCEPTABLE) End-to- end Delay < 100 ms < 150 ms< 400 ms NOTE: The delay for best effort class is a target value. Table 4: End-to-end delay for TIPHON Systems

Specification of QoS Parameters -- Ongoing and Planned Work IPPM RFCs Planned –Loss Patterns –Bulk Transfer Capacity I-Ds Received –Packet Reordering –Msmt Protocol Rqmts –MIB Newly Chartered Work –Link BW Capacity 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, …)