78
This presentation is the property of its rightful owner.
Sponsored Links
1 / 13

Hitoshi Asaeda (Keio University) PowerPoint PPT Presentation


  • 93 Views
  • Uploaded on
  • Presentation posted in: General

78 th IETF, Maastricht, Netherlands, July 2010. IGMP/MLD-Based Explicit Membership Tracking Function for Multicast Routers draft-asaeda-mboned-explicit-tracking-00. Hitoshi Asaeda (Keio University). Objectives. Problem in bursty IGMP/MLD message transmission

Download Presentation

Hitoshi Asaeda (Keio University)

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.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Hitoshi asaeda keio university

78th IETF, Maastricht, Netherlands, July 2010

IGMP/MLD-Based Explicit Membership Tracking Function for Multicast Routersdraft-asaeda-mboned-explicit-tracking-00

Hitoshi Asaeda

(Keio University)

78th IETF, July 2010, Maastricht


Objectives

Objectives

  • Problem in bursty IGMP/MLD message transmission

    • Especially in the recent IGMPv3/MLDv2/LW-IGMPv3/LW-MLDv2 due to elimination of the report suppression mechanism

    • Requirement to save wireless network resources (in multimob WG)

  • Requirement of fast leave or shortening leave latency

78th IETF, July 2010, Maastricht


Functions

Functions

  • The explicit tracking function on routers (described in a separate draft) works for:

    • Per-host accounting

    • Reducing the number of transmitted Query and Report messages

    • Shortening leave latencies

    • Maintaining multicast channel characteristics (or statistics)

78th IETF, July 2010, Maastricht


Objective 1 the number of messages transmission

Objective 1: the Number of Messages Transmission

  • Whenever a router receives the State-Change Report, it sends the corresponding Group-Specific or Group-and-Source Specific Query messages to confirm whether the Report sender is the last member host or not.

78th IETF, July 2010, Maastricht


Current state report regular case

Current-State Report – Regular Case

  • Responses for General Query

  • Responses for Group- (and-Source) Specific Query

78th IETF, July 2010, Maastricht


Lower specific query transmission

Lower Specific Query Transmission

  • A router enabling the explicit tracking function does not need to always ask Current-State Report message transmission to the member hosts whenever it receives the State-Change Report

    • Because the explicit tracking function works with the expectation that the State-Change Report sender is the last remaining member of the channel

78th IETF, July 2010, Maastricht


Current state report with explicit tracking function

Current-State Report – With Explicit Tracking Function

  • Responses for General Query

  • No responses for Group- (and-Source)

    Specific Query

0h 20m

78th IETF, July 2010, Maastricht


Outdated state information

Outdated State Information

  • When a router expects that the State-Change Report sender was the sole member, but not the one, or when the number of receivers in the state information becomes “0”, but not “0”;

    • Other members remaining in the same channel will reply with identical Report messages

  • When a router expects that there are other members, but there isn’t, or when the number of receivers in the state information is not “0”, but it is “0”;

    • The router sends periodical General Query later but does not receive the corresponding Report; it then starts the leave operation

    • Will add some intelligence (e.g., send State-Change Report when the number of remaining members is less than “5”, etc.)

78th IETF, July 2010, Maastricht


Objective 2 leave latency

Objective 2: Leave Latency

  • [Last Member Query Interval] (LMQI) and [Last Listener Query Interval] (LLQI)

    • The maximum time allowed before sending a responding Report

  • [Last Member Query Count] (LMQC) and [Last Listener Query Count] (LLQC)

    • The number of Group-Specific Queries or Group-and-Source Specific Queries sent before the router assumes there are no local members

  • [Last Member Query Time] (LMQT) and [Last Listener Query Time] (LLQT)

    • Total time the router should wait for a report, after the Querier has sent the first query

78th IETF, July 2010, Maastricht


Shortening leave latencies

Shortening Leave Latencies

  • [Last Member Query Timer (LMQT)] and [Last Listener Query Timer (LLQT)]

    • Default: LMQI/LLQI * LMQC/LLQC (= 2 sec.)

    • Shorter value contributes to shortening leave latency

    • Proposal

      • LMQC/LLQC = 1, thus LMQT/LLQT = 1 sec.

      • Note, LMQI/LLQI can be shorter, e.g., 0.5 sec.

  • Note

    • The risk that a router misses Report messages from remaining members will be increased if the router adopts small LMQC/LLQC

    • However the wrong expectation would be lower happened for the router enabling the explicit tracking function.

78th IETF, July 2010, Maastricht


Membership state information

Membership State Information

  • Complete state information

    • (S, G, number of receivers, (receiver records))

  • Minimum state information

    • (S, G, number of receivers)

    • Pro.: Minimizing memory usage

    • Con.: No accounting support

  • ASM

    • “S” is with “Null”

  • EXCLUDE mode

    • Not integrate state information

    • Just keep the current state without modification

78th IETF, July 2010, Maastricht


Interoperability and compatibility

Interoperability and Compatibility

  • Not work for old IGMP/MLD

    • Because of Report suppression mechanism

    • Keep the current state as is

  • Not work for IGMPv3/MLDv2 router changing its compatibility mode to the older version

    • Keep the current state as is

78th IETF, July 2010, Maastricht


Next step

Next Step

  • WG document?

78th IETF, July 2010, Maastricht


  • Login