Configuring MTU Discovery for BGP Sessions

You can configure TCP path maximum transmission unit (MTU) discovery. MTU discovery improves convergence times for IBGP sessions. BGP unconditionally disables TCP path MTU discovery, resulting in a 512-byte MSS on TCP sessions that are not directly connected. This feature allows you to to enable TCP path MTU discovery on BGP sessions.

To configure MTU discovery, include the mtu-discovery statement:

mtu-discovery;

For a list of hierarchy levels at which you can include this statement, see the statement summary section for this statement.