Protocols which can be encapsulated in IP datagrams must be assigned a Protocol Number as defined in RFC2780. This number is used in an 8 bit field the IP header ("Protocol" in IPv4, "Next Header" in IPv6) to identify the encapsulated protocol. Due to the limited range of available values, it is desirable to recycle numbers, although not sought in general by the IESG. Current assignments may be found at http://www.iana.org/assignments/protocol-numbers. The Datagram Congestion Control Protocol (recently approved) has requested from IANA that it be permitted to reuse the Protocol Number 33, currently assigned to the Sequential Exchange Protocol (SEP). It is believed that this protocol has not been used for many years. The protocol author, Jon Crowcroft, confirms this view. This note initiates a two week last call (to end 3 June 2005) to solicit any indication that SEP is in active use. If there is no indication by the date above, the IESG will let IANA know that Protocol Number 33 may be assigned to DCCP, and that the use of 33 for SEP will be considered OBSOLETE. Public comments may be sent to ietf@ietf.org. Private comments may be sent to the Responsible Area Director, Allison Mankin, <mankin-at-psg.com>. _______________________________________________ IETF-Announce@ietf.org https://www1.ietf.org/mailman/listinfo/ietf-announce