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Here is an overview of a subset of the presentations that took place during Hiroshima’s meeting
  1. Pierre Francois: Clarification to the treatment of BGP non-transitive extended communities (draft-decraene-idr-rfc4360-clarification). The implementations tested by the authors do not behave in the same way. One implementation removes the community upon reception on an eBGP session. The authors of the draft highlight that section 6 of RFC 4360 says that non-transitive extended communities SHOULD not be transmitted on eBGP session. Since it is a “SHOULD” and not a “MUST”, the authors suggest that when such a community is received on an eBGP session, it is not stripped from the BGP update. It is important to fix this behavior should BGP graceful shutdown be performed using a non-transitive extended community instead of the current allocated community. Using a non-transitive extended community will simplify the filters that currently need to be configured to confine graceful shutdown to the local ASs.
  2. Pierre Francois: Analysis of the path selection modes proposed for add-path (draft-vvds-add-paths-analysis). In the “session type” mode (not described in the draft), the ASBRs advertise all paths to their RRs and on iBGP sessions of type “over”. RRs advertise the 2 best paths to their iBGP clients. This mode seems the most interesting to me, if the RRs can manage to hold all the routes.
  3. Bruno Decraene: Requirements for BGP graceful shutdown (draft-ietf-grow-bgp-graceful-shutdown-requirements). It is important to provide a solution to reduce connectivity/packet losses upon the maintenance of a BGP session. Bruno asked that the draft be last called. After the presentation of the requirements, Pierre presented one solution that does not require modifications to BGP, only configurations of BGP filters. The presentation was followed by operators coming to the mic. They were afraid that the solution be more complex than what they do today. For example, one of them uses AS-path prepending. He does not care about having 0 packet loss. Thus, tunnels are not needed (too expensive). However, he would benefit from the proposal relying on low loc-pref setting. This will ensure that traffic be redirected away from the maintained resources. This is not always the case with AS-path prepending. This is because the AS-path length comes after the loc-pref in the BGP decision process.

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November 17th, 2009 at 6:47 pm

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