The ip routing table shows that I have 4 routes to reach

#show ip route, ubest/mbest: 4/0
*via x.x.16.6, [20/0], 2d, bgp-64500, external, tag 64500
*via x.x.17.4, [20/0], 2d, bgp-64500, external, tag 64500
*via x.x.18.2, [20/0], 2d, bgp-64500, external, tag 64500
*via x.x.19.0, [20/0], 2d, bgp-64500, external, tag 64500

However, when I see which ones are advertised to the neighbor, I only see one:

show ip bgp neighbors 10.x.x.x advertised-routes 
Network               Next Hop            Metric     LocPrf    Weight Path
*>e0.0.0.0/0          x.x.17.4                              0 64500 100 i

Is this default behavior of BGP? If yes, how does BGP choose which route to advertise out of 4?

  • Is my question missing some information?
    – monica
    Oct 25 '18 at 2:03
  • All the routes have exactly same attributes. If it has to come to RID, it should have been x.x.16.6. However, why it is 17.4 is not clear to me. Also, the BGP path selection process is used to decides which prefixes to install in the IP routing table. All of the prefixes are installed in the route table due to multipath enabled.
    – monica
    Oct 26 '18 at 18:50

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