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Introduction

An NSLP for Quality of Service Slides: http://users.skynet.be/besvand1/draft-ietf-nsis-qos-nslp-01-ietf58.ppt. Georgios Karagiannis , Andrew McDonald , Sven V an den Bosch, Attila Bader , Maarten Buchli , Hannes Tschofenig, Robert Hancock Cornelia Kappler, Eric Waegeman , Lars Westberg

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Introduction

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  1. An NSLP for Quality of ServiceSlides: http://users.skynet.be/besvand1/draft-ietf-nsis-qos-nslp-01-ietf58.ppt Georgios Karagiannis, Andrew McDonald, Sven Van den Bosch,Attila Bader, Maarten Buchli, Hannes Tschofenig, Robert Hancock Cornelia Kappler, Eric Waegeman, Lars Westberg IETF#58 – Minneapolis November 2003

  2. Introduction • NSIS needs to specify a signalling layer protocol for signalling ‘Quality of Service’ • IETF 57: 3 (independent) individual submissions • draft-buchli-nsis-nslp-00.txtdraft-mcdonald-nsis-qos-nslp-00.txtdraft-westberg-proposal-for-rsvpv2-nslp-00.txt • WG decided to have joint WG QoS NSLP draft • Draft-ietf-nsis-qos-nslp-00.txt • Draft-ietf-nsis-qos-nslp-01.txt

  3. Draft overview • Key Components: • Interchangeable QoS Models • Small set of message types • State changing: RESERVE • Non-state changing: QUERY, RESPONSE, NOTIFY • Draft also: • Gives a basic outline of operation • Gives specific requirements on NTLP functionality

  4. Basic protocol structure • Draft focuses on header and Common Control Information header Common Control Info QoS-model specific Control Info QSpec Policy

  5. Message semantics & types • RESERVE: Messages affecting state installation at NSLP • Reserve, Refresh, Commit, Modify, Tear • QUERY: Message collecting path characteristics • Query • RESPONSE: Message responding to RESERVE or QUERY • Ack, Nack, Query_reply • NOTIFY: Unsolicited NSLP messages • Notify

  6. QSpec vs QoS model • QoS model: Mechanism for providing QoS as a whole • Examples: IntServ, DiffServ, RMD • Local or global • QSpec: Set of parameters and values describing requested resources (for flows with QoS requirements) • Two options: by example or by template (currently proposed) • Open issues • How to document QoS models? • Default QoS model? • How to handle local QoS implementations? • Stack new Qspec at edge of QoS model domain? • RMF Interpretation of QSpec in each QNE? • What if you get an unknown QoS model?

  7. Control Information • Indicates how the message should be handled by QNE • 2 kinds • common CI (useful for many QoS models): one, applies to whole message • ResponseRequest • RSN • QoS-model specific CI (only for QoS model specific stuff): one per QSpec • TTL? • Requestor IP address?

  8. Scoping • Restrict the propagation of messages to QNEs • Downstream: limit QUERY on path-characteristics to “sub”-path • Upstream: avoid propagation of RESPONSE beyond requestor • Not for NOTIFY: independent decision per hop • Scoping is done by introducing Control Information • 'back to me' (RII), 'next hop' and 'whole path‘ seem obvious • Open issues: • Are there others that seem useful? • “as far as my QoS model is supported”, “only in AS x”, “until three hops away” • Are they adequately covered by QoS-model specific CI?

  9. Some NTLP requirements • Support for stateless/reduced state operation: OK • Support for SII • Detecting change of NSLP peer: OK • Explicit routing: not necessarily supported • Should be available over API • Last node detection needs to be made explicit • Performance requirements • Partly addressed by messaging associations (parallel ones can handle signalling message priority) • Fast rerouting discovery (NSLP responsible for new reservation) • API impact: expressed as a hint but may be overruled in some cases

  10. Mailing list issues • Adressed in –01 • RSN versus Session ID • session IDs still need to be present and aren't replaced by RSNs. • how QoS-NSLP could react once it notes that it maintains stale state. • Message types • Why not only RESERVE and RESPONSE? • Clarified figure 1 is not an implementation restriction

  11. Mailing list issues (2) • Left for –0x • Summary refreshes: include which objects? Only previous RSN? • Statemaintenance requirements table • SSM support? • QoS model (example, template) -> see previous slides • Nesting of QoS models • Stacking of Qspecs/CI • Relation to/overlap with tunnel management

  12. Provide comments!

  13. Backup Slides Yet more detail

  14. RESERVE • Unique properties: • Processing it changes signalling application state; in particular authorisation matters more for RESERVE than other messages • Requires associated lifetime • Idempotent: only care about the latest in sequence • Contains: • QSpec object • Flags (Tear bit, New/Old state, …) • Source Identification Information (SII): keeps track of upstream (stateful) neighbour(s) • Locally significant Reservation Sequence Number (RSN): indicates order of state modifying actions • Sent peer-to-peer

  15. QUERY • Gathers information along the data path • Does not change reservation state • Does not cause NSLP state to be installed • Contains ResponseRequest object • May be scoped

  16. RESPONSE • Provides information about the effect/result of a previous QoS-NSLP message • Referenced by Response Identification Info (RII) • Upstream forwarding does not imply existence of reverse path state • Direct passing may be achieved locally by keeping track of Source Identification Info (SII)

  17. NOTIFY • Used to convey information, typically error conditions • Sent asynchronously • Does not refer to installed state • Does not trigger or mandate any action

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