Routing

Hi 

I peer EBGP woth cisco router. Status of BGP stuck in Connect state 

Output of log is below

May 17 10:56:30.470657 task_timer_reset: reset BGP_4652.61.19.60.1_Connect
May 17 10:56:30.470666 task_timer_set_oneshot_latest: timer BGP_4652.61.19.60.1_Connect interval set to 1:04
May 17 10:56:34.464676 task_process_events_internal: connect ready for BGP_4652.61.19.61.1
May 17 10:56:34.464714 bgp_connect_complete: error connecting to 61.19.61.1 (External AS 4652): Unknown error: -880758492
May 17 10:56:34.464718 BGP peer 61.19.61.1 (External AS 4652) CLOSE: close socket 88
May 17 10:56:34.464720 task_close: close socket 88 task BGP_4652.61.19.61.1
May 17 10:56:34.464723 task_reset_socket: task BGP_4652.61.19.61.1 socket 88
May 17 10:56:34.464750 bgp_event: peer 61.19.61.1 (External AS 4652) old state Connect event OpenFail new state Idle
May 17 10:56:34.464900 bgp_event: peer 61.19.61.1 (External AS 4652) old state Idle event Start new state Connect
May 17 10:56:34.464906 bgp_connect_start: peer 61.19.61.1 (External AS 4652)
May 17 10:56:34.464909 bgp_event: peer 61.19.61.1 (External AS 4652) old state Connect event ConnectRetry new state Connect
May 17 10:56:34.464937 task_get_socket: domain AF_INET type SOCK_STREAM protocol 0 socket 88
May 17 10:56:34.464954 task_set_option_internal: task BGP_4652.61.19.61.1 socket 88 option RecvBuffer(0) value 16384
May 17 10:56:34.464963 task_set_option_internal: task BGP_4652.61.19.61.1 socket 88 option SendBuffer(1) value 16384
May 17 10:56:34.464966 task_set_socket: task BGP_4652.61.19.61.1 socket 88
May 17 10:56:34.464983 task_set_option_internal: task BGP_4652.61.19.61.1 socket 88 option NonBlocking(8) value 1
May 17 10:56:34.464992 task_set_option_internal: task BGP_4652.61.19.61.1 socket 88 option ReUsePort(38) value 1
May 17 10:56:34.465008 task_set_option_internal: task BGP_4652.61.19.61.1 socket 88 option PathMTUDiscovery(26) value 0
May 17 10:56:34.465018 task_set_option_internal: task BGP_4652.61.19.61.1 socket 88 option TOS(16) value 192
May 17 10:56:34.465028 task_set_option_internal: task BGP_4652.61.19.61.1 socket 88 option DontRoute(5) value 1
May 17 10:56:34.465037 task_set_option_internal: task BGP_4652.61.19.61.1 socket 88 option IifRestrict(36) value 1
May 17 10:56:34.465045 task_set_option_internal: task BGP_4652.61.19.61.1 socket 88 option TTL(15) value 1
May 17 10:56:34.465060 task_set_option_internal: task BGP_4652.61.19.61.1 socket 88 option TcpAggressiveTransmission(59) value 0
May 17 10:56:34.465157 task_timer_reset: reset BGP_4652.61.19.61.1_Connect
May 17 10:56:34.465166 task_timer_set_oneshot_latest: timer BGP_4652.61.19.61.1_Connect interval set to 1:04

What's wrong??

Hi Halo,

Please verify IP connectivity to the peer (61.19.61.1?) and ensure the far end is configured with the correct BGP neighbor IP etc..  It seems we don't get a response from the other side.  

show system connections | grep <peer IP>

Hope this helps.

Regards,
-r.

--------------------------------------------------

If this solves your problem, please mark this post as "Accepted Solution."
Kudos are always appreciated :).

Are you able to ping the peer ip and telent on port 179? share the output of following commands:

show route 61.19.61.1

ping 61.19.61.1

telnet 61.19.61.1 port 179

Hi Halo, 

-Try matching BGP configuration in both sides , this will be useful, something like

 **Check if peer address/ AS number configured incorrectly on either router.

**Any other BGP configuration error.

-Is this Multihop using lo0? Try using TTL higher than 1

-Make you don’t have a firewall filter blocking port 179 on either side.

-Verify L3 connectivity – icmp

Please Mark My Solution Accepted if it Helped, Kudos are Appreciated too! 🙂

Hello,

---

@Halo  wrote:

 

What's wrong??

---

Most probably Your lo0.0 filter which does not allow return packets from peer.

HTH

Thx
Alex

Hi Halo,

First of what is connect state of BGP?

In connect  state, bgp waits for a TCP conn. to be completed. It starts ConnectRetry timer and  then If it is successful to establish TCP connection then the local router will send an OPEN message to the bgp peer(external or internal) and the BGP state machine transitions to the OpenSent state. However, if the TCP connection attempt fails, the local bgp router resets the ConnectRetry timer and transitions to the Active state. Additionally, depending on the failure condition, the local router could also revert back to the Idle state. Additionally, if the ConnectRetry timer reaches 0 while the local router is in the Connect state, the timer is reset and another connection attempt is made. In this case, the local router remains in the Connect state.

In your case TCP connection establishment is the problem.

Possiblity 1.

   Local router is sending TCP connection request to 61.19.61.1, but peer is not able to process it.

        1. Could be configuration issue for peering address on Cisco router.

        2. Check Policy on Cisco router if any access-list configured to deny packet from 61.19.61.1 on port 179(BGP application port).

        3. Cisco router is busy in processing other request which is queing TCP request from local peer. Check CPU utilization or other hw problem could be there.

       4. Check for any CoPP policy on cisco router.

Possiblity 2.

       Local router is sending TCP connection request to 61.19.61.1, but peer is not able to recieve it on their side.

            1. It could be issue on link congestion, check end-end path by continues ping, encountering any ping loss. 

            2. If possible check if any Firewall inbetween check the policy in it, port 179 is allowed for communication between local router and cisco router.

          3. Check for any QoS policy.

Please feel free to reply back with any queries...

For how much time, it is staying in Connect State or it stucked in this state for long(go for clear bgp; hsad reset). I am considering ur BGP Config is ok at both end.

Also is ConnectRetryTimer reinitiating or not???