BGP Route Redistribution – Internal Peers

The figure shown below depicts the topology setup used for this configuration.

Figure 1. BGP Configuration and Testing Topology


Use the following commands to configure BGP routing.

  1. To enable BGP in Router R1:

    Execute the following commands:

    • Enter the Global Configuration Mode.
    iS5comm# configure terminal
    • Enter the Autonomous System (AS) number in R1.
    iS5comm(config)# as-num 100
    • Configure the router-id in R1.
    iS5comm(config)# router-id 12.0.0.1
    • Enable BGP in R1.
    iS5comm(config)# router bgp 100
    • Configure R2 (with as-num 100) as internal peer in R1.
    iS5comm(config-router)# neighbor 12.0.0.2 remote-as 100

  2. To enable BGP in Router R2:

    Execute the following commands:

    • Enter the Global Configuration Mode.
    iS5comm# configure terminal
    • Enter the Autonomous System (AS) number in R2.
    iS5comm(config)# as-num 100
    • Configure the router-id in R2.
    iS5comm(config)# router-id 12.0.0.2
    • Enable BGP in R2.
    iS5comm(config)# router bgp 100
    • Configure R1 (with as-num 100) as internal peer in R2.
    iS5comm(config-router)# neighbor 12.0.0.1 remote-as 100

  3. Verify that the BGP session between the internal peers R1 and R2 is established, using the following show commands in R1 and R2.

    Type the following:

    • R1: View the bgp summary information.
    iS5comm# show ip bgp summary
    BGP router identifier is 12.0.0.1, local AS number 100
    BGP table version is 0
    Neighbor Version AS MsgRcvd MsgSent Up/DownState/PfxRcd
     -------------------------------- ----------------
    12.0.0.2  4     100  2      2        00:00:00:23 Established

    iS5comm# show ip bgp neighbor
    BGP neighbor is 12.0.0.2, remote AS 100, external link
    BGP version 4, remote router ID 12.0.0.2
    BGP state = Established, up for 3 minutes 11 seconds
    Configured BGP Maximum Prefix Limit 100
    Configured Connect Retry Count 5
    Current Connect Retry Count 0
    Peer Status : NOT DAMPED
    Idlehold time is 20 DelayOpen interval is 50 secs
    Rcvd update before 0 secs, hold time is 120, keepalive interval is 30 secs
    Neighbors Capability:
    Route-Refresh: Advertised and received
    Address family IPv4 Unicast: Advertised and received
    Received 8 messages, 0 Updates
    Sent 8 messages, 0 Updates
    Route refresh: Received 0, sent 0.
    Minimum time between advertisement runs is 30 seconds
    Connections established 1 time(s)
    Local host: 12.0.0.1, Local port: 179
    Foreign host: 12.0.0.2, Foreign port: 49152
    Last Error: Code 0, SubCode 0

    • R2: View the BGP summary information.
    iS5comm# show ip bgp summary
    BGP router identifier is 12.0.0.2, local AS number 100
    BGP table version is 0
    Neighbor Version AS MsgRcvd MsgSent Up/DownState/PfxRcd
    -------- ------- ---- -------------- ----------------
    12.0.0.1    4    100   2      2   00:00:00:6 Established

    • View the peer details for the neighbor.
    iS5comm# show ip bgp neighbor
    BGP neighbor is 12.0.0.1, remote AS 100, internal link
    BGP version 4, remote router ID 12.0.0.1
    BGP state = Established, up for 31 minutes 38 seconds
    Configured BGP Maximum Prefix Limit 100
    AutomaticStart ENABLED
    DelayOpen ENABLED
    Configured Connect Retry Count 5
    Current Connect Retry Count 0
    Peer Status : NOT DAMPED
    Idlehold time is 20 DelayOpen interval is 60 secs
    Rcvd update before 0 secs, hold time is 90, keepalive interval is 30 secs
    Received 63 messages, 0 Updates
    Sent 63 messages, 0 Updates
    Route refresh: Received 0, sent 0.
    Minimum time between advertisement runs is 5 seconds
    Connections established 1 time(s)
    Local host: 12.0.0.2, Local port: 179
    Foreign host: 12.0.0.1, Foreign port: 49152
    Last Error: Code 0, SubCode 0.

    • Add static route in R1:
    iS5comm# configure terminal
    iS5comm(config)# ip route 91.0.0.0 255.0.0.0 20.0.0.2
    iS5comm(config)# exit
    iS5comm# show ip route
    C 12.0.0.0/8 is directly connected, vlan1
    C 20.0.0.0/8 is directly connected, vlan2
    S 91.0.0.0/8 [-1] via 20.0.0.2

    • In R1, redistribute the static route into BGP.
    iS5comm# configure terminal 
    iS5comm(config)# router bgp 100
    iS5comm(config-router)# redistribute static
    iS5comm(config-router)# end

    • Verify the BGP route in R2.
    iS5comm# show ip bgp rib
    BGP table version is 1,local router ID is 12.0.0.2
    Status codes: d damped* valid, > best, i - internal
    Origin codes: i - IGP, e - EGP, ? - incomplete
    Network Next Hop Metric LocPrf Path
    ------- ---- --- ------------ ----
    *>i   91.0.0.0/8 12.0.0.1 100   ?

    • iS5comm# show ip route
    C 12.0.0.0/8 is directly connected, vlan1B 91.0.0.0/8 [-1] via 12.0.0.1

    • Delete the static route in R1.
    iS5comm# configure terminal
    iS5comm(config)# no ip route 91.0.0.0 255.0.0.0 20.0.0.2
    iS5comm(config)# end

    iS5comm# show ip route
    C 12.0.0.0/8 is directly connected, vlan1
    C 20.0.0.0/8 is directly connected, vlan2
    In R2 verify that BGP route is not present after deletion of the static route in R1

    iS5comm# show ip bgp rib
    BGP table version is 0, local router ID is 0.0.0.0
    Status codes: d damped * valid, > best, i - internal
    Origin codes: i - IGP, e - EGP, ? - incomplete
     Network Next Hop Metric LocPrf Path
    ------- ---- --- ------ ------ ----

    iS5comm# show ip route
    C 12.0.0.0/8 is directly connected, vlan1
Parent topic: BGP Configuration