BGP Notification received message with dead time expired

[tanmoymm91]

R1---R2 is running with ibgp .

I checked the configuration like AS number , MTU as well MSS setting on both side . looks good and symmetric .

both side MTU is 1500 bytes . we have set the MSS as 1460 bytes also on both side .

what should be the possible reasons for this error .

Note : for security issues i will not be able to share the configurations here 

[MHM Cisco World]

Disable pmtu discover if you hardcoded the mtu.

Ping ibgp Peer IP with repeat 100 check if there is any drop.

[tanmoymm91]

ping having intermitted drop .

MTU is by default with 1500 bytes

[MHM Cisco World]

Share the ping result 

[MHM Cisco World]

If there are success and then some failed 

Check interface output drop'

Adjust the queue of interface.

[Joseph W. Doherty]

The new information of ping drops does point toward lost BGP packets are the likely cause.

However, "Adjust the queue of interface." might require some thought.  You can easily make the same problem worse or create other issues.

In general, routing protocol packets are important.  Cisco's BGP, I believe, marks such packets with IPPrec 6.

[Joseph W. Doherty]

"Disable pmtu discover if you hardcoded the mtu."

Why?

[DanielP211]

Is connectivity OK, are they pingble between each other, is there any firewall inbetween? Are the router peers in the same subnet? 
You can change the configuration of IP's and AS number and paste it for reference. 

[Joseph W. Doherty]

A possible reason is loss of BGP packets on a heavily loaded path.

[tanmoymm91]

are you saying about the bandwidth congestion in underlying link ?

[Joseph W. Doherty]

Possibly.

Just noting loss of BGP packets, between BGP peers, is a possible cause.  If that's happening, why/where needs analysis.

As BGP peers don't need to be directly connected, not uncommon for iBGP peers (which your OP mentions), which is why I wrote path, not link or interface.

[Joseph W. Doherty]

Although, unlikely related to your issue, just curious:

Did you configure "MTU" or "IP MTU"?  For either, why?

You configured MSS with what command?  Why?