This lab will configure all three routers to form iBGP relationships with each other.

1. Add a neighbor statement to R3 from R1 and vice-versa.
   1. Answer R1

      router bgp 65000
       neighbor 10.0.1.3
        remote-as 65000
        address-family ipv4 unicast

   2. Answer R3

      router bgp 65000
       neighbor 10.0.0.2
        remote-as 65000
        address-family ipv4 unicast

2. Verification

   1. RP/0/0/CPU0:R3#show bgp summ
      Neighbor        Spk    AS MsgRcvd MsgSent   TblVer  InQ OutQ  Up/Down  St/PfxRcd
      10.0.0.2          0 65000     107     107     4080    0    0 01:43:16          2
      10.0.1.2          0 65000    1127    1127     4080    0    0 18:43:48          3

   2. RP/0/0/CPU0:R3#show bgp nei 10.0.0.2 | i BGP state
      BGP state = Established, up for 01:44:11

   3. RP/0/RP0/CPU0:R1#show route bgp
      Tue Feb  4 13:54:01.083 UTC
      
      B    2.2.2.2/32 [200/0] via 10.0.0.3, 00:04:04
      B    3.3.3.3/32 [200/0] via 10.0.1.3, 00:01:00
      B    10.0.1.0/24 [200/0] via 10.0.0.3, 00:04:04

   4. RP/0/RP0/CPU0:R2#show route bgp
      Tue Feb  4 13:55:08.321 UTC
      
      B    1.1.1.1/32 [200/0] via 10.0.0.2, 00:05:11
      B    3.3.3.3/32 [200/0] via 10.0.1.3, 00:05:11

   5. RP/0/RP0/CPU0:R3#show bgp nei 10.0.0.2 | i BGP state
      Tue Feb  4 13:53:30.051 UTC
        BGP state = Established, up for 00:00:35
      RP/0/RP0/CPU0:R3#show route bgp
      Tue Feb  4 13:53:37.832 UTC
      
      B    1.1.1.1/32 [200/0] via 10.0.0.2, 00:00:01
      B    2.2.2.2/32 [200/0] via 10.0.1.2, 00:03:42
      B    10.0.0.0/24 [200/0] via 10.0.0.2, 00:00:01

   6. Now R1 and R3 have an iBGP relationship. All this was done without creating a directly connected full-mesh topology.

   7. RP/0/RP0/CPU0:R3#ping 10.0.0.1
      Tue Feb  4 14:02:42.197 UTC
      Type escape sequence to abort.
      Sending 5, 100-byte ICMP Echos to 10.0.0.1, timeout is 2 seconds:
      !!!!!
      Success rate is 100 percent (5/5), round-trip min/avg/max = 143/163/181 ms
      RP/0/RP0/CPU0:R3#ping 10.0.0.2
      Tue Feb  4 14:02:47.192 UTC
      Type escape sequence to abort.
      Sending 5, 100-byte ICMP Echos to 10.0.0.2, timeout is 2 seconds:
      !!!!!
      Success rate is 100 percent (5/5), round-trip min/avg/max = 158/185/204 ms
      RP/0/RP0/CPU0:R3#ping 10.0.0.3
      Tue Feb  4 14:03:00.589 UTC
      Type escape sequence to abort.
      Sending 5, 100-byte ICMP Echos to 10.0.0.3, timeout is 2 seconds:
      !!!!!
      Success rate is 100 percent (5/5), round-trip min/avg/max = 89/114/166 ms

IOS-XR Lab 7: iBGP with Three Routers part 3
IOS-XR Lab Index