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Forum Replies

  1. Hi Rene,
    Ur explanation was good…plz also describes about BGP Route Reflectors and Confederations.

  2. Hi Hamood,

    Good question, there’s a good explanation for this:

    1. iBGP requires a full mesh of peerings because of iBGP split horizon. This is why we use loopback interfaces instead of physical interfaces for the peering. Physical interfaces can go down, loopbacks can’t (unless you shut them). In this example I could have used physical interfaces since there is only one link between R2-R3 and R3-R4, if we had a link between R2-R4 then it would have been a must.

    2. When R4 (or R2) advertises its network on the loopback interface to R3 then R3 will store it in its

    ... Continue reading in our forum

  3. Hello Minh,

    It sounds like you have a good understanding of these concepts :slight_smile:

    ISPs / service providers often use MPLS in their core networks yes. One of the advantages is that you don’t have to run iBGP on each and every core router. I have a lesson where I explain this:


    On the P and PE routers, we use an IGP like OSPF or IS-IS, on the PE routers we use iBGP.

    VRFs are often used in MPLS VPN where you want customer routing to be separated 100%. You don’t really need this for just Internet access. With MPLS VPN

    ... Continue reading in our forum

  4. actually it is helpful. I have ran into that in the work place. I just was so focused I was not seeing it. I have actually ran into that in the work environment. where we had a bgp prefix of a customer and we needed to test to see if they could get outside the ISP network. My initial pings did not work because of something similar here where the IP being used by default by the ping was not the correct one and we had to use the source command. So that is vey similar to this except in those cases it was actual public IPs and not loopbacks. However, now

    ... Continue reading in our forum

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