Appendix E. TCP Options that May Be Used with BGP

If a local system TCP user interface supports the TCP PUSH function, then each BGP message SHOULD be transmitted with PUSH flag set. Setting PUSH flag forces BGP messages to be transmitted to the receiver promptly.

If a local system TCP user interface supports setting the DSCP field [RFC2474] for TCP connections, then the TCP connection used by BGP SHOULD be opened with bits 0-2 of the DSCP field set to 110 (binary).

An implementation MUST support the TCP MD5 option [RFC2385].

RFC 4271 BGP-4 January 2006