Check BGP Sessions
Purpose
Display summary information about BGP and its neighbors to determine if routes are received from peers in the autonomous system (AS). When a BGP session is established, the peers are exchanging update messages.
Action
To check that BGP sessions are up, enter the following Junos OS CLI operational mode command from the ingress router:
Sample Output 1
user@R1> show bgp summary Groups: 1 Peers: 6 Down peers: 1 Table Tot Paths Act Paths Suppressed History Damp State Pending inet.0 1 1 0 0 0 0 Peer AS InPkt OutPkt OutQ Flaps Last Up/Dwn State|#Active/Received/Damped... 10.0.0.2 65432 11257 11259 0 0 3d 21:49:57 0/0/0 0/0/0 10.0.0.3 65432 11257 11259 0 0 3d 21:49:57 0/0/0 0/0/0 10.0.0.4 65432 11257 11259 0 0 3d 21:49:57 0/0/0 0/0/0 10.0.0.5 65432 11257 11260 0 0 3d 21:49:57 0/0/0 0/0/0 10.0.0.6 65432 4 4572 0 1 3d 21:46:59 Active 10.1.36.2 65432 11252 11257 0 0 3d 21:46:49 1/1/0 0/0/0
Sample Output 2
user@R1> show bgp summary Groups: 1 Peers: 5 Down peers: 0 Table Tot Paths Act Paths Suppressed History Damp State Pending inet.0 1 1 0 0 0 0 Peer AS InPkt OutPkt OutQ Flaps Last Up/Dwn State|#Active/Received/Damped... 10.0.0.2 65432 64 68 0 0 32:18 0/0/0 0/0/0 10.0.0.3 65432 64 67 0 0 32:02 0/0/0 0/0/0 10.0.0.4 65432 64 67 0 0 32:10 0/0/0 0/0/0 10.0.0.5 65432 64 67 0 0 32:14 0/0/0 0/0/0 10.0.0.6 65432 38 39 0 1 18:02 1/1/0 0/0/0
Meaning
Sample Output 1 shows that one peer (egress router 10.0.0.6 ) is not established, as indicated by the Down Peers: 1 field. The last column (State|#Active/Received/Damped) shows that peer 10.0.0.6 is active, indicating that is it not established. All other peers are established as indicated by the number of active, received, and damped routes. For example, 0/0/0 for peer 10.0.0.2 indicates that no BGP routes were active or received in the routing table, and no BGP routes were damped; 1/1/0 for peer 10.1.36.2 indicates that one BGP route was active and received in the routing table, and no BGP routes were damped.
If the output of the show bgp summary command of an ingress router shows that a neighbor is down, check the BGP configuration. For information on checking the BGP configuration, see Verify the BGP Configuration.
Sample Output 2 shows output from ingress router R1 after the BGP configurations on R1 and R6 were corrected in Take Appropriate Action. All BGP peers are established and one route is active and received. No BGP routes were damped.
If the output of the show bgp summary command shows that a neighbor is up but packets are not being forwarded, check for received routes from the egress router. For information on checking the egress router for received routes, see Verify Received BGP Routes.
