Extensions to RFC4379 in Support of Link Bundles draftnadeaurfc4379bislinkbundle00'txt

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Extensions to RFC4379 in Support of Link
Bundlesdraft-nadeau-rfc4379-bis-link-bundle-00.tx
t

• Tom Nadeau
• George Swallow
• Danny Prairie
• David Ward

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Requirements/Motivations

• Customers have run into some issues where link
  bundles are deployed which RFC4379 cannot
  correctly isolate.
• They have requested extending RFC4379 to solve
  this problem.
• Solution must be backwards compatible with
  implementations that do not support extensions.
• Solution must support different load balancing
  schemes used for Link Bundles.

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How This Works

• Extend existing Echo Request packet from RFC4379
  to include a new Link Bundle TLV.
• Modify the definition of the existing downstream
  mapping TLV slightly to clarify the semantics
  when link bundles need to be revealed at
  midpoints.
• Enhance downstream mapping TLV processing
  algorithm to support processing of the new TLV at
  the sender (source).

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New TLV Encoding at Midpoints

• Midpoints will encode the downstream interface
  mapping as they do today. When encountering link
  bundle interfaces, they should include the link
  bundle interface in the DSMap TLV. Midpoints must
  not include component links here, however.
• Midpoints will create an instance of the new
  Downstream Map Link Bundle TLV for each LB
  interface inserted into the DSMAP TLV (above).
• This TLV points back to the DSMap for the LB
  interface.
• For each component link, it must encode it here.

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Receiver Processing

• Process DSMap TLV as is done today, but when
  encountering DSLB TLV, process through this, and
  then link this to the associated LB interface
  from the DSMap TLV. This information can then be
  used in a manner similar to what is done today to
  probe the next ply in the ECMP tree.

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Open Issues and Next Steps

• Draft needs another round of editing.
• Is this a reasonable place to start on this work?
• Should we accept this as a WG doc to satisfy this
  charter item?
• Define requirements and mechanisms for MPLS OAM