bgp networks and subnet on the same router

Discussion in 'Cisco' started by pomidorek, Dec 27, 2007.

  1. pomidorek

    pomidorek Guest

    Helo


    I have network a.b.c.d/23 in my bgp configuration on my c28xx

    On the same router on my LAN interface i'd like divide clas /23 on some
    subnets 4x a.b.c.d/25 etc and i have problem. When i configure
    subnets , my bgp stop advertise my prefix /23. When i delete subnets and
    i configure a.b.c.1/23 bgp works good.

    There is possible to advertise in BGP prefix /23 and simultaneously have
    some subnets ?

    thx for help

    best regards

    Pet
     
    pomidorek, Dec 27, 2007
    #1
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  2. pomidorek

    pomidorek Guest

    pomidorek pisze:
    some outputs i conf

    sh ip route
    C A.B.C.0/24 is directly connected, GigabitEthernet0/0
    C A.B.C+1.0/24 is directly connected, Vlan2

    sh ip bgp neighbors [ip] advertised-routes

    Total number of prefixes 0


    my conf
    router bgp [as]
    no synchronization
    bgp router-id [ip]
    bgp log-neighbor-changes
    network A.B.C.0 mask 255.255.254.0
    neighbor [ip] remote-as [as]
    neighbor [ip] next-hop-self
    neighbor [ip] filter-list 4 in
    no auto-summary

    Pet
     
    pomidorek, Dec 27, 2007
    #2
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  3. pomidorek

    pcmccollum Guest

    Pet,

    Can you post your bgp configuration as well as your 'show ip bgp'
    output?

    neteng
    http://blog.humanmodem.com
     
    pcmccollum, Dec 27, 2007
    #3
  4. pomidorek

    pomidorek Guest

    pisze:
    sh ip route
    C 192.168.10.0/24 is directly connected, GigabitEthernet0/0
    C 192.168.11.0/24 is directly connected, Vlan2

    sh ip bgp neighbors [20.20.20.1] advertised-routes

    Total number of prefixes 0

    my conf
    router bgp [as]
    no synchronization
    bgp router-id [192.168.10.1]
    bgp log-neighbor-changes
    network 192.168.10.0 mask 255.255.254.0
    neighbor [20.20.20.1] remote-as [as]
    neighbor [20.20.20.1] next-hop-self
    neighbor [20.20.20.1] filter-list 4 in
    no auto-summary

    Pet

    Pet,
    ok I correct above
    Pet
     
    pomidorek, Dec 27, 2007
    #4
  5. pomidorek

    Merv Guest

    BGP network statement causes the local route to be advertised by BGP
    ONLY if the route is in the RIB (main routing table) when you split
    the subnet then the original route is no longer in the RIB


    All you need to do is create a summary route in the RIB for the
    original /23 subnet:


    ip route 192.168.10.0 mask 255.255.254.0 null0


    router bgp <>
    network 192.168.10.0 mask 255.255.254.0
     
    Merv, Dec 27, 2007
    #5
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