1# SIP - Session Initiation Protocol - Internet telephony - RFC 3261 2# Pattern attributes: ok fast fast 3# Protocol groups: voip ietf_proposed_standard 4# Wiki: http://www.protocolinfo.org/wiki/SIP 5# 6# This pattern has been tested with the Ubiquity SIP user agent. 7# 8# Thanks to Ankit Desai for this pattern. 9# 10# SIP typically uses port 5060. 11# 12# This pattern is based on SIP request format as per RFC 3261. I'm not 13# sure about the version part. The RFC doesn't say anything about it, so 14# I have allowed version ranging from 0.x to 2.x. 15 16#Request-Line = Method SP Request-URI SP SIP-Version CRLF 17sip 18^(invite|register|cancel) sip[\x09-\x0d -~]*sip/[0-2]\.[0-9] 19