====IOS-XR Lab 4: Advertising iBGP====

  - Advertise the Loopback and G 0/0/0/0 interface on both routers. Be patient, BGP neighborship will form. Sometimes it could take a few mins for that neighborship to form.
    - ++Answer|<code>RP/0/0/CPU0:R1(config)#router bgp 65000
RP/0/0/CPU0:R1(config-bgp)#address-family ipv4 unicast 
RP/0/0/CPU0:R1(config-bgp-af)#network 10.0.0.0/24
RP/0/0/CPU0:R1(config-bgp-af)#network 1.1.1.1/32
RP/0/0/CPU0:R1(config-bgp-af)#commit </code>
<code>RP/0/0/CPU0:R2(config)#router bgp 65000
RP/0/0/CPU0:R2(config-bgp)#address-family ipv4 unicast 
RP/0/0/CPU0:R2(config-bgp-af)#network 10.0.0.0/24
RP/0/0/CPU0:R2(config-bgp-af)#network 2.2.2.2/32
RP/0/0/CPU0:R2(config-bgp-af)#commit</code> ++
  - Verify
    - <code>RP/0/0/CPU0:R1#show bgp ipv4 unicast
BGP router identifier 1.1.1.1, local AS number 65000
   Network            Next Hop            Metric LocPrf Weight Path
*> 1.1.1.1/32         0.0.0.0                  0         32768 i
*>i2.2.2.2/32         10.0.0.3                 0    100      0 i
*> 10.0.0.0/24        0.0.0.0                  0         32768 i
* i                   10.0.0.3                 0    100      0 i

Processed 3 prefixes, 4 paths</code>
    - <code>RP/0/0/CPU0:R2#show bgp ipv4 unicast
BGP router identifier 2.2.2.2, local AS number 65000
   Network            Next Hop            Metric LocPrf Weight Path
*>i1.1.1.1/32         10.0.0.2                 0    100      0 i
*> 2.2.2.2/32         0.0.0.0                  0         32768 i
*> 10.0.0.0/24        0.0.0.0                  0         32768 i
* i                   10.0.0.2                 0    100      0 i

Processed 3 prefixes, 4 paths</code>
    - <code>RP/0/0/CPU0:R1#show bgp ipv4 unicast neighbors 10.0.0.3 advertised-routes 
Mon Dec 16 20:58:58.809 UTC
Network            Next Hop        From            AS Path
1.1.1.1/32         10.0.0.2        Local           i
10.0.0.0/24        10.0.0.2        Local           i

Processed 2 prefixes, 2 paths</code>
    - <code>RP/0/0/CPU0:R2#show bgp ipv4 unicast neighbors 10.0.0.2 advertised-routes 
Mon Dec 16 20:59:45.226 UTC
Network            Next Hop        From            AS Path
2.2.2.2/32         10.0.0.3        Local           i
10.0.0.0/24        10.0.0.3        Local           i

Processed 2 prefixes, 2 paths</code>
    - <code>RP/0/0/CPU0:R1#show route bgp
Mon Dec 16 21:00:48.261 UTC

B    2.2.2.2/32 [200/0] via 10.0.0.3, 00:16:35</code>
    - <code>RP/0/0/CPU0:R2#show route bgp
Mon Dec 16 21:00:54.761 UTC

B    1.1.1.1/32 [200/0] via 10.0.0.2, 00:19:33</code>
    - Notice the [200/0] next to the neighbor's address. The 200 is the Administrative Distance (AD). An AD of 200 means iBGP whereas eBGP would be 20.

[[:cisco:labs:ios_xr:lab5|IOS-XR Lab 5: iBGP]]\\ 
[[:cisco:labs:ios_xr|IOS-XR Lab Index]]