2.2.6 Via Header Field Extensions

This protocol defines new Via header field parameters and their values. The original ABNF, as defined in [RFC5234], for the Via header field in [RFC3261] section 25 is extended as follows:

via-params = via-ttl / via-maddr / via-received /via-branch
             / via-branched
             / via-ms-internal-info 
             / via-ms-received-port 
             / via-ms-received-cid 
             / via-extension
via-branched = "branched=" ("TRUE" / "FALSE")
via-ms-internal-info = "ms-internal-info=" quoted-string
via-ms-received-port = "ms-received-port=" port
via-ms-received-cid  = "ms-received-cid=" token

token, quoted-string, and port are defined in [RFC3261] section 25.1.