BGP Route Reflection diagram

feature

I had plans to cover Nokia (Alcatel-Lucent) BGP Route Reflectors (BGP RR) in a full-featured post, but… But a lot of new stuff suddenly hit me as I joined Nuage Networks team.

Ok, lyrics aside, during my preparation for BGP exam I noticed that BGP route reflectors behavior defined throughout several chapters and there was no summary diagram (or cheatlist) that covered route reflectors decisions and actions. So, here you are:

This diagram shows the complete decision path of a BGP RR when it needs to reflect a route, including action items for different kind of neighbors (Non-client, Client, regular peer).

Note, that Nokia’s (Alcatel-Lucent) definitions were used for RIB structures (RIB-In, RIB-Out), though the decisions that RR has to make should no differ between vendors.

Download high-resolution file.

Roman Dodin

Network engineer at Nokia
Eagerness to learn multiplied by passion to share.
You can reach me at LinkedIn

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  • Anton Marchenko

    Roman,

    Thanks for reminding essentials BGP RR concepts.

    Paying attention to details do you think it would more correct to say that BGP best path selection happens on routes in LOC-RIB, so if the path was not selected as best it should be kept in LOC-RIB, not in RIB-IN. Because RIB-IN basically holds all received routes from a neighbor before applying import policies.

    • http://hellt.ru/ Roman Dodin

      Anton, this is subject to a vendor-specific definitions. At Nokia we use RIB-IN as a first loop in a chain of BGP routes memory structures. See this diagram http://img-fotki.yandex.ru/get/4109/21639405.11c/0_84d72_94e5a74a_XL.png for a clean picture

      • Anton Marchenko

        Roman,

        Thanks for explanation. I just thought those structures correspond to RFC4271 conceptual RIB model where you have Adj-RIB-In per neighbor, after import policies routes go to Loc-RIB where best path selection happens and after export policies routes finally land in per neighbor Adj-RIB-Out.

  • ahmed karim

    Perfect Roman, many thanks