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QoS Standards Challenges for NGNs

QoS Standards Challenges for NGNs. Charles Dvorak, AT&T Labs ATIS GSC Delegation. QoS—what is it, and what about the NGN?. A well-accepted definition from ITU-T E.800 :

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QoS Standards Challenges for NGNs

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  1. QoS Standards Challenges for NGNs Charles Dvorak, AT&T Labs ATIS GSC Delegation GSC-9, Seoul

  2. QoS—what is it, and what about the NGN? A well-accepted definition from ITU-T E.800: “the collective effects of service performance which determine the degree of satisfaction of a user of the service.” (This means QoS is always really E2E.) Will QoS be important for NGNs? Every industry forum that has addressed this issue has concluded the answer is an emphatic “YES!” For example, at the 2002 ATIS VoIP Summit, service providers agreed that inadequate QoS for future, IP-based services was “a potential show-stopper.” GSC-9, Seoul

  3. A QoS framework that applies to any service (G.1000) GSC-9, Seoul

  4. Four Views of QoS (G.1000) that always apply (PSTN, ISDN, NGN) GSC-9, Seoul

  5. Needed QoS Steps: The IETF circa 2000 The IAB’s RFC 2990 “Next Steps for the IP QoS Architecture” compared IntServ and DiffServ style networks and considered broader architectural approaches / requirements, including critical “gaps” in routing; resource management; monitoring and accounting; application and service development; and incremental, heterogeneous deployment. Conclusion: What is needed is “a set of QoS mechanisms and a number of ways these mechanisms can be configured to interoperate in a stable and consistent fashion” GSC-9, Seoul

  6. QoS Issues, circa 2002 (still valid !) • Most carriers today zero out any QoS-related bits(ToS, DiffServ) of incoming packets and look atnothing but the IP destination address • IP routing protocols route around failures, notcongestion (some have congestion indicatorstelling sender to use less B/W…no good for VoIP) • QoS monitoring is dependent on the types of securearchitectures (MPLS nets, IPsec VPNs, SSL VPNs…) • Scalability, security and restorability still big issues • Full IP integration of service types still a pipe dream GSC-9, Seoul

  7. State of E2E IP QoS in 2004 • Application requirements are known; needed QoSclasses defined; monitoring metrics widely used • QoS is not just per-domain but end-to-end and thus has to be signaled / provisioned across networks.Requirements for needed protocols largely done;now very active positioning on different solutions. • Much work needed to ensure these solutions are: • Reliable, secure and scalable • Capable of supporting all traffic/service mixes/priorities • Resilient regarding any between-layer dependencies (e.g., rapid restoration of QoS as well as lower layers) GSC-9, Seoul

  8. A way forward, based onITU-T Y.1541 and Y.1221 Together, the two Recommendations specify the key data needed for IP network QoS signaling. • Y.1541:QoS classes quantify user application needs in terms of IP network performance • Y.1221: “traffic contract” complements QoS class by describing flow characteristics/limits GSC-9, Seoul

  9. Y.1541 - IP QoS Classes and NI-NI Objectives GSC-9, Seoul

  10. Y.1541 Guidance for IP QoS Classes GSC-9, Seoul

  11. Traffic Contract IP Transfer Capability QoS Class Traffic Descriptor (Y.1541) • Max Pkt Size • Token Bucket • Rate (Rp, Rs) • Size (Bp, Bs) • Dedicated BW • Statistical BW • Best Effort Y.1221: Traffic and CongestionControl in IP Based Networks (conditions under whichQoS specs can be met) GSC-9, Seoul

  12. Service Level Parameters to be Signaled (came partly out of ATIS VoIP Summit in 2002) • Y.1541 QoS class (objective numerical levels for IP Loss Ratio, IP Transfer Delay, and IP Delay Variation may be indicated by specifying the Y.1541 QoS class itself as a signalling parameter) • Traffic Parameters from Y.1221 • Peak rate (Rp) • Peak bucket size (Bp) • Sustainable rate (Rs) • Sustainable bucket size (Bs) • Maximum allowed packet size (M) • IP DSCP (optional) as specified in RFC 2474 • Priority/reliability of the service GSC-9, Seoul

  13. UNI NNI GW GW GW GW Network Assumed Network Functionality • Subscription Verification • Authentication • Call Admission Control • Performance Management GSC-9, Seoul

  14. IPCablecomQoS (J.163): Segmented signalling model GSC-9, Seoul

  15. Segmented signalling model …but what if the path looks like: Wireless w/3GPP sig. ISP-1(Intserv) BB-1(Diffserv) BB-2(MPLS-TE) ISP-2(over-prov) Cable xDSL? GSC-9, Seoul

  16. What does the NGN need for e2e QoS?(The following currently being proposed in ATIS) • A standard set of IP network QoS classes and associated traffic descriptors, for characterizing end-to-end IP packet flows in managed IP networks (or alternatively, more than one specification and an associated set of interworking standards for mapping among them). • Standard signaling capabilities enabling independent operators of managed IP networks to cooperate in establishing end-to-end IP flows supporting particular user-requested QoS classes and traffic profiles. • Standards (or guidelines) for relating signaled QoS and traffic specifications with network resource sharing mechanisms capable of supporting them. GSC-9, Seoul

  17. Progress towards E2E QoS • Requirements for an e2e QoS protocol are being developed in SG11. • IP QoS Signaling "proofs of concept" are being kicked around in the IETF's NSIS WG. AT&T recently submitted :http://www.ietf.org/internet-drafts/draft-ash-nsis-nslp-qos-sig-proof-of-concept-01.txt , which is based on 3 ITU-T QoS signaling items: • [TRQ-QoS-SIG] "Signaling Requirements for IP-QoS," January 2004. • [Y.1541] "Network Performance Objectives for IP-Based Services," 2002. • [E.361] "QoS Routing Support for Interworking of QoS Service Classes Across Routing Technologies," 2003. Also, the ATIS VoIP Focus Group has identifiedneeded action, such as a standards work plan to achieve the needed signaling for E2E QoS. GSC-9, Seoul

  18. Parting Comments on End-to-End QoS • Y.1541/Y.1221 specs exist for NI-to-NI IP QoS, but there is no widely accepted delivery mechanism yet • Still unclear if QoS-related resource control of others’ networks will ever be allowed; even if some carriers agree, interoperability is still an issue • Over-provisioning still central to many solutions • No forum is advancing Reliability and Restoration mechanisms for e2e IP QoS in any tangible way yet • Recent attention on IP emergency communications have served as a magnet for all of the shortcomings of e2e QoS proposals in IP space (IETF’s IEPREP) GSC-9, Seoul

  19. BACKUP SLIDES GSC-9, Seoul

  20. Scope of SG11 QoS Signaling Reqts. GSC-9, Seoul

  21. One Approach: E2E Session Control GSC-9, Seoul

  22. Another approach: No Session Control GSC-9, Seoul

  23. Application Level QoS SignallingH.323 Annex N H.323 Annex N H.323 Annex N Vertical QoS Signalling(H.trans.cont) Transport Level QoS Signalling(H.trans.cont or NSIS) Approach of SG 16 (see new H.360) Service Domain 2 Service Domain1 Application Plane Transport Plane Transport Domain 1 Transport Domain 3 Transport Domain 2 Packet Flow QoS Signalling Call Signalling GSC-9, Seoul

  24. Edge Router Service Control Server Transit Router Core Router Bearer Resource Manager Proposed (AAP) ITU-T Y.1291 Appendix–An architectural framework for support of quality of service (QoS) in packet networks Service Control Layer Bearer Control Layer Bearer Layer LSP GSC-9, Seoul

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