Recommendation ITU-T H.460.26 enables ITU-T H.323 devices under the condition where UDP transport is unavailable to transport media and control that otherwise would be transported over UDP to be tunnelled through the ITU H.225.0 Signalling Channel over TCP. This extension may be used in conjunction with ITU-T H.460.17 "Using H.225.0 Call Signalling Connection as transport for H.323 RAS Messages" to facilitate the transportation of RAS, Signalling (ITU-T H.225.0), Control (ITU-T H.245) and Media Packets (RTP/RTCP/SRTP/SRTCP) over a signal TCP Channel.