One Line Learning Posts - 3 BGP

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 Today we will cover some confusing options of the BGP

1). Route Dampening is only working for eBGP routes. It will not trigger on iBGP route. This technique is applied when receiving updates from external peers only (EBGP). Applying this technique to IBGP learned routes or to advertisement to IBGP or EBGP peers after making a route selection can result in routing loops.

2).  Peer Group: Since IOS version 12 manual peer group configuration is no longer necessary to achieve this optimization. IOS is capable of recognizing neighbors with the same outbound policy. These are then grouped together automatically. This is a feature called Dynamic Update Peer Groups. You can check the Dynamic groups using the command "show IP bgp update-group" command.  Changing a policy in out direction to a neighbor will also change the update group in the backend. 


3). Simplifying Route Reflector rule: Books say there are three rules. But as per my complete understanding of this point, I am remembering only one rule as non-Client routes will not advertise to other non-Client. Why? Because both non-clients are behaving the same as iBGP neighbors (BGP loop Prevention).  There is no other boundary for Router Reflector to stop advertising normal updates (Don't ignore BGP basic)

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