Reg:IBGP routes issue

Hi All,

I have litlle confusion about ibgp functionality.As we know in EBGP we use AS path information to prevent loops.But if we receive a route from a IBGP peer then why we do not advertise the same route to that ibgp peer.As we know in case of RR we use cluster-id to prevent loops but what we use in ibgp.Bgp split-horizon rule says that routes learned via a n ibgp peer will not advertise to another ibgp peer as it assumes that ibgp is fully meshed but why we cann't advertise the route to the same ibgp peer from which we learned the router.

Please help me.

Thanks

Comments

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    Be careful with your wording or you will irritate Anthony.  :)  There
    is not "split horizon" in BGP, but the rules makes it LIKE split
    horizon.  hehehehe.



    But I think you answer your own question there.  And you do find
    instances where the same route IS passed both directions, but if I
    learn a route from you, the only reason I'll pass the same route back
    to you is if I have something better.   If the route FROM you is my
    bestpath, why would I tell you about it, because you're already telling
    me!



    HTH,






     



    Scott Morris, CCIEx4
    (R&S/ISP-Dial/Security/Service Provider) #4713,

    JNCIE-M #153, JNCIS-ER, CISSP, et al.

    CCSI #21903, JNCI-M, JNCI-ER

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    vinod kumar wrote:

    Hi All,

    I have litlle confusion about ibgp functionality.As we know in
    EBGP we use AS path information to prevent loops.But if we receive a
    route from a IBGP peer then why we do not advertise the same route to
    that ibgp peer.As we know in case of RR we use cluster-id to prevent
    loops but what we use in ibgp.Bgp split-horizon rule says that routes
    learned via a n ibgp peer will not advertise to another ibgp peer as it
    assumes that ibgp is fully meshed but why we cann't advertise the route
    to the same ibgp peer from which we learned the router.

    Please help me.

    Thanks







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