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Forum Replies

  1. Dear Ahammad,

    You have to configure this on all routers within the sub-AS otherwise they won’t consider themselves part of the confederation. They will be able to establish BGP peerings but they’ll consider other routers in the confederation as regular “external” or “internal” neighbors. They will also drop routes when they see a confederation path in it.

    I tested this, here is the output of some show commands when I removed “bgp confederation identifier 2” on R3, R4 and R5:

    R3#show ip bgp 11.11.11.11
    BGP routing table entry for 11.11.11.11/32, version 19
    Paths
    ... Continue reading in our forum

  2. Dear Rene,

    Thanks for the information. Yes that is correct.

    However, I simulated a similar lab like yours but I have not connected R4 and R5 that you have done, only to see if those router can communicate with R1. And i found out that if i don’t connect R4 and R5 to each other as redundant link then those two router do not need the “bgp confederation peer” and “bgp confederation identifier” commands. Also I found out that those two commands are mandatory for R2 and R3. Since, R2 is connecting External AS router R1 and Internal “sub-as” router R3 and R3 is con

    ... Continue reading in our forum

  3. Hi Rene

    Thank you for this article.

    I had a question though

    When R1 advertises route to R2 that’s external and learned via ebgp. For ibgp protocol states that next hop advertised by ebgp should be carried into ibgp. So when R1 advertises 11.11.11.11 to R2 it uses next hop address as 192.168.12.1. So when R2 advertises this route to its ibgp peers it should have next hop as 192.168.12.1 and not as 2.2.2.2 .
    Is this case we can also use next-hop-self command ? or using igp like ospf is the only option?

    thank you
    Kandhla

  4. Hi Kandhla,
    Yes, you can absolutely use the next-help-self option with iBGP. In fact, in some circumstances you might HAVE to. For example, let’s say you have a router (R1) with an external BGP relationship with an ISP, and your highly available site has been given two separate circuits from that ISP. To ensure that R1’s BGP neighborship with the ISP is also highly available, you have configured R1 to use the ISP’s router’s loopback address (you would also have to use the ebgp-multihop option for this). To do this you would create static routes on R1 to get

    ... Continue reading in our forum

  5. Hello Rene,

    Can you tell me if in GNS we have any kind of incompatibility with Confederations.

    I did a lab on the GNS3 Cisco Router 7200, when I set up EBGP between R1 x R2 look at the messages.

    Configurations?
    R1:

    //cdn-forum.networklessons.com/uploads/default/original/2X/2/2b804a9288f1a203138adf9432e8585bf9172b5f.png

    R2:

    //cdn-forum.networklessons.com/uploads/default/original/2X/d/d213fce0433b3dcda9f17b6555084c5ff4172666.png

    AS error:
    R2:

    //cdn-forum.networklessons.com/uploads/default/original/2X/6/690796f4d5e52196e9312ebe7a2ede994caa82a1.png


    R1:

    //cdn-foru

    ... Continue reading in our forum

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