Cisco Cisco IOS Software Release 12.2(33)SRE

Border Gateway Protocol (BGP) support for Transmission Control Protocol (TCP) path maximum 
transmission unit (MTU) discovery introduces the ability for BGP to automatically discover the best 
TCP path MTU for each BGP session. TCP path MTU discovery is enabled by default for all BGP 
neighbor sessions, but you can disable, and subsequently enable, the TCP path MTU globally for all BGP 
sessions or for an individual BGP neighbor session.

Configuration information is included in the “Configuring BGP Neighbor Session Options” chapter of 
the 

, Release 12.4T, at the following URL:

Command reference information is included in the Cisco IOS IP Routing Protocols Command Reference, 
Release 12.2SR, at the following URL:

The following commands are new or modified for this feature:

Any Internet Protocol (IP) addresses used in this document are not intended to be actual addresses. Any examples, command display output, and 
figures included in the document are shown for illustrative purposes only. Any use of actual IP addresses in illustrative content is unintentional and 
coincidental.

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