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  1. Rene,

    If this has been answered by other members I apologize but following your example, the RR works as configured as R3 does learn about the prefix but its not being installed in the routing table because it can not reach the next hop address of To resolve this I added the next-hop-self command on R1 and reset the BGP peerings. That still did not resolve this.

    My question is once a RR is configured should all the clients update their next hop to the RR or should the originator of the prefix have the next-hop-self configuration?

    R3#sh ip bgp
    BGP routing table entry for, version 0
    Paths: (1 available, no best path)
      Not advertised to any peer
      Refresh Epoch 2
      Local (inaccessible) from (
          Origin IGP, metric 0, localpref 100, valid, internal
          Originator:, Cluster list:
          rx pathid: 0, tx pathid: 0


    R1#sh running-config | section router bgp
    router bgp 123
     bgp log-neighbor-changes
     network mask
     neighbor remote-as 123
     neighbor next-hop-self
  2. Hi Michael,

    In this example R1 originates the prefix so the next hop is

    R2 will reflect this prefix to R3 but it doesn’t change the next hop. Using next-hop self on R1 won’t help here since is already the next hop IP address.

    The route reflector will reduce the number of iBGP peerings but that’s it :slight_smile:

    About your question, let’s imagine that R1 learns from an eBGP router. In this case, it would be better to make R1 the RR and use “next hop self” for all other iBGP routers. That would ensure that all iBGP neighbors learn the prefix and are able to reach it.


  3. Udaya,
    In the case of a router’s being a route reflector client of multiple route reflectors, the client will accept routes from all reflectors. In other words, all learned routes will be present in the BGP topology table. As far as which routes are selected as best routes, and installed in the routing table, the client will use the standard (and complex!) BGP best path selection algorithm.

  4. I need a bit of help, I can’t seem to get this working on Real Equip or GNS3

    I have the following setup; http://imgur.com/a/ZLqCl

    But R1 still cannot ping the address assigned on loopback 0 on R3. I’ve got some outputs below, let me know if you need more :slight_smile: Hope someone can help me figure what i’ve done wrong

    R1 - http://paste.ubuntu.com/23460781/ http://paste.ubuntu.com/23460783/
    R2 - http://paste.ubuntu.com/23460788/ http://paste.ubuntu.com/23460789/
    R3 - http://paste.ubuntu.com/23460791/ http://paste.ubuntu.com/23460793/

    What I can see is R1 is showing inaccessible for the next hop of However even if R2 has “Next-Hop-Self” enabled the Next Hop Address doesn’t change?

  5. Hey Ryan,
    The issue you are having is that while R1 knows about the BGP route to R3, it is not installing it into the routing table. You can verify this by going on to R1 and issuing a “show ip bgp” and look for the route (it will be missing the “>” symbol).

    The reason R1 is not installing the route is due to BGP behaving differently than other routing protocols. BGP really isn’t a true routing protocol in the way that OSPF or EIGRP are. BGP is more of an application that tells you WHERE to go to get to a network, but it does not tell HOW to get there. So, for example, BGP is telling R1 to get to, go to It is up to R1 to figure out HOW to get to In this case, R1 doesn’t know how to get to

    I suspect you know all of this, which is why you are trying to configure R2 to be a next-hop-self for R1. The problem with this solution is that, by default, BGP only modifies this attribute on routes it learns from external neighbors–not internal neighbors.

    So to solve this problem, you have four options:

    1. Configure R3 in a different BGP ASN than R2
    2. Configure R2 to advertise the and networks in BGP
    3. Configure either static routes or an IGP so that R1, R2, and R3 know about all the links connecting them
    4. If you have a late enough version of the IOS, R2 will have a new option of “neighbor next-hop-self all” where this option allows the modification of either internally or externally learned BGP routes.

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