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.

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STP/RSTP election process

Just a quick reminder on STP election process (thanks to Dmitry Figol):

  1. Choose Root bridge:
    1. lowest Bridge ID (priority + system mac)
    2. all ports on a Root bridge are designated
  2. Choose Root port on each non-root bridge:
    1. lowest path cost to the root
    2. lowest neighbor Bridge ID
    3. lowest neighbor’s Port ID (port priority + internal port number)
    4. lowest local Port ID (port priority + internal port number)
  3. Choose Designated port on each segment.
    1. bridge with the lowest root path cost
    2. bridge with the lowest Bridge ID
    3. interface with the lowest Port ID
  4. All other ports are non-designated/blocking

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