--On 03 June 2004 01:15 +0200 Jiri Kuthan <jiri at iptel.org> wrote: > In RFC3261, use of Contacts is mandatory. That's not the case in RFC2543 > which was a bug. Ah! the final part of the jigsaw. The SIP book (written by an RFC author) seems to predate RFC3261 (at least in parts). Thanks. Now all sorted I think. Alex