CCNP - BGP - Packetracer limitations?

Node ManNode Man Member Posts: 668 ■■■□□□□□□□
Hi Everyone,
I'm trying to figure out if I am doing something wrong, or if this is a Packettracer limitation: I believe that I read that BGP neighbors do not have to belong in the same subnet, however, in Packettracer will not form an adjacent neighbor unless the BGP routers are in the same subnet. Am I doing something wrong?



  • fredrikjjfredrikjj Member Posts: 879
    That depends. It could be a Packttracer limitation, but it could also be you not fully understanding how BGP's TCP session works.
  • networker050184networker050184 Mod Posts: 11,962 Mod
    I think fredrikjj hit it on the head with the TCP session part.
    An expert is a man who has made all the mistakes which can be made.
  • HeeroHeero Member Posts: 486
    That being said, if you are at the CCNP level and doing BGP labs, you should step your game up and use something like GNS3, or VIRL, or CSR1000Vs, or IOU.
  • Node ManNode Man Member Posts: 668 ■■■□□□□□□□
    One reason I love this forum is its proactive attitude. We clearly have already upgraded to protocol ToughLove V2.

    I'll will take the advice above. Loading up GNS3 icon_smile.gif
  • FitziFitzi Member Posts: 40 ■■■□□□□□□□
    I'm not sure about packet tracer as I have never used it but to give another hint, as the other guys have alluded to, have a think about reachability between your two bgp speakers.
  • _Gonzalo__Gonzalo_ Member Posts: 113
    Node Man wrote: »
    I believe that I read that BGP neighbors do not have to belong in the same subnet,

    Firstly, I agree with you upgrading to GNS3 or similar. It is tough to let packet tracert go, but you really have no choice, as for advanced routing and high availavility (to give you two examples) you can´t use it.

    And now, about your question, routing goes after connectivity. No connectivity, no routing. That said, in BGP there is no need for two routers to be directly connected to be neighbors, as you can set the hops needed to reach the neighbor that you defined.

    Hope it helped!
  • HondabuffHondabuff Member Posts: 667 ■■■□□□□□□□
    You can use the "neighbor ip-address ebgp-mutihop number-of-hops command" Used for peering to loopback addresses. If connecting to a loopback address with the neighbor ip-address update-sourceinterface command. The dumb things you remember while doing NP studies.
    “The problem with quotes on the Internet is that you can’t always be sure of their authenticity.” ~Abraham Lincoln
  • Node ManNode Man Member Posts: 668 ■■■□□□□□□□
    Hi Guys,
    Thank for the good advice. Here were the steps I took:

    1) used GNS2
    2) watched some youtube videos
    3) found my major snag: properly setting up the "ip route" command:
    ip route

    I got the loopback working. Now I am going to wash - rinse - repeat a few more times.

    Thanks again!
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