Clearmode supports for transporting/signalling clear channel data in ISDN over RTP as per RFC 4040. When an AS- SIP (Assured Services) signalling appliance receives a Q.931 SETUP message, where the bearer capability IE indicates that the bearer is 64 kbps unrestricted, then it will generate an outbound INVITE that includes the "SDP" parameters as specified in RFC 4040. The media ("m=")will be assigned the value audio. The attribute ("a=") will be assigned the value CLEARMODE/8000.
When an AS-SIP appliance receives an INVITE intended for the TDM network where m=audio and a=CLEARMODE/8000, the signaling applicance creates a Q.931 SETUP message with the bearer capability IE indicating that the bearer is 64 Kbps unrestricted.
For ISDN over VTP, the "Data" codec is used for transporting clear channel data over RTP.
SCIP over RTP supports native clear media traffic. The terminal supports clear, regular codecs like G.711 and G.729.
Signaling support of clear channel calls must be completed using SCIP-214.2. Support for SCIP over RTP will be declared as a dynamic RTP/AVP (Audio Video Profile) payload type of 126.
Session Description Protocol (SDP) is used to declare support for the SCIP over RTP session. In the cases where Secure RTP (SRTP) is negotiated, all of the RTP based media will be protected.
These instructions assume VX builder is installed and running.
To enable transporting/signaling clear channels, the following configuration options must be configured in the VX.
For ISDN over VTP, the "Data" codec must be configured to support RFC 4040 implementation.
For SCIP over RTP mode, signaling support of clear channels must be done use SCIP-214.2. The "SCIP" codec must be configured to support SCIP-214.2 (SCIP over RTP mode).