1 / 8

Accurate ECN Feedback

Accurate ECN Feedback. Mirja Kühlewind Richard Scheffenegger tools.ietf.org/html/draft-kuehlewind-tcpm-accurate-ecn-02 tools.ietf.org/html/draft-kuehlewind-tcpm-accurate-ecn-option-01. Motivation. Enable improvements in TCP congestion reaction based on detailed ECN feedback

rajah-davenport
Download Presentation

Accurate ECN Feedback

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Accurate ECN Feedback Mirja Kühlewind Richard Scheffenegger tools.ietf.org/html/draft-kuehlewind-tcpm-accurate-ecn-02tools.ietf.org/html/draft-kuehlewind-tcpm-accurate-ecn-option-01 89th IETF, London, UK

  2. Motivation • Enable improvements in TCP congestion reaction based on detailed ECN feedback • ECN (RFC3168) limits feedback signal • MUST match with requirements http://tools.ietf.org/html/draft-ietf-tcpm-accecn-reqs-05 89th IETF, London, UK

  3. Updates since IETF88 • Focus on Requirements Document • Acc ECN using Codepointswould use existing header bits only • Segment granularity • Acc ECN TCP Option would use 12 byte option • Payload byte granularity easily possible 89th IETF, London, UK

  4. AccECN feedback using codepoints • Redefinition of the ECN TCP flags: +-----+----+-----+-----+------------+------------+ | ECI | NS | CWR | ECE | CI (base5) | E1 (base3) | +-----+----+-----+-----+------------+------------+ | 0 | 0 | 0 | 0 | 0 | - | | 1 | 0 | 0 | 1 | 1 | - | | 2 | 0 | 1 | 0 | 2 | - | | 3 | 0 | 1 | 1 | 3 | - | | 4 | 1 | 0 | 0 | 4 | - | | 5 | 1 | 0 | 1 | - | 0 | | 6 | 1 | 1 | 0 | - | 1 | | 7 | 1 | 1 | 1 | - | 2 | +-----+----+-----+-----+------------+------------+ • Auxiliary signaling in unused URG pointer field: • Only when URG flag not set • May be cleared by middleboxes with limited impact 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+ | | | | Reserved | Top ACE | | | | +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+ 89th IETF, London, UK

  5. AccECN TCP option • New TCP option • Allows much higher granularity Kind: TBD Length: 12 bytes +------+------+---------+---------+-------+-------+-------+-----------+ | Kind | 12 | ECT(0) | ECT(1) | CE |non-ECT| loss |CE in bytes| +------+------+---------+---------+-------+-------+-------+-----------+ 1 1 2 2 1 1 1 3 • Additional refinements possible • Consolidate counters for bytes only (except loss) • RFC6994 experimental option 89th IETF, London, UK

  6. TCP ECN mechanisms 89th IETF, London, UK

  7. Next steps • Discussion of proposals on list • Adoption of a mechanism once the requirements are accepted 89th IETF, London, UK

  8. 89th IETF, London, UK

More Related