SOURCE:ATIS TITLE:The challenges of E2E QoS for NGNs AGENDA ITEM:GTSC-2; #5.2 CONTACT:Charles Dvorak, GSC9/GTSC_ GSC-9, Seoul QoS Standards Challenges for NGNs Charles Dvorak, AT&T Labs ATIS GSC Delegation

GSC-9, Seoul 2 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.” QoS—what is it, and what about the NGN?

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 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” Needed QoS Steps: The IETF circa 2000

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 at nothing but the IP destination address IP routing protocols route around failures, not congestion (some have congestion indicators telling sender to use less B/W…no good for VoIP) QoS monitoring is dependent on the types of secure architectures (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 State of E2E IP QoS in 2004 Application requirements are known; needed QoS classes 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 on ITU-T Y.1541 and Y.1221 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 Together, the two Recommendations specify the key data needed for IP network QoS signaling.

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

GSC-9, Seoul 10 Y.1541 Guidance for IP QoS Classes QoS Class Applications (Examples)Node Mechanisms Network Techniques 0 Real-Time, Jitter Sensitive, High Interaction (VoIP, VTC) Separate Queue with Preferential Servicing, Traffic Grooming Constrained Routing/Distance 1 Real-Time, Jitter Sensitive, Interactive (VoIP, VTC) Less Constrained Routing/ Distance 2 Transaction Data, Highly Interactive (Signalling) Separate Queue, Drop Priority Constrained Routing/Distance 3 Transaction Data, Interactive Less Constrained Routing/ Distance 4 Low Loss Only (Short Transactions, Bulk Data, Video Streaming) Long Queue, Drop Priority Any Route/Path 5 Traditional Applications of Default IP Networks Separate Queue (Lowest Priority) Any Route/Path

GSC-9, Seoul 11 Y.1221: Traffic and Congestion Control in IP Based Networks Traffic Contract Dedicated BW Statistical BW Best Effort Max Pkt Size Token Bucket –Rate (Rp, Rs) –Size (Bp, Bs) (Y.1541) IP Transfer Capability Traffic Descriptor QoS Class (conditions under which QoS 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 Assumed Network Functionality Subscription VerificationSubscription Verification AuthenticationAuthentication Call Admission ControlCall Admission Control Performance ManagementPerformance Management GW Network UNI GW NNI

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

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

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 : of-concept-01.txt, which is based on 3 ITU-T QoS signaling items: 1)[TRQ-QoS-SIG] "Signaling Requirements for IP-QoS," January )[Y.1541] "Network Performance Objectives for IP-Based Services," )[E.361] "QoS Routing Support for Interworking of QoS Service Classes Across Routing Technologies," Also, the ATIS VoIP Focus Group has identified needed 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 Call Signalling Packet Flow QoS Signalling Application Plane Transport Plane Approach of SG 16 (see new H.360) Service Domain 1 Transport Domain 1 Transport Domain 2 Transport Domain 3 Service Domain 2 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

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