Call Trace - SRTP - Outbound INVITE

The IMG 2020 has negotiated an SRTP cryptosuite on the incoming side. Now it is time to transmit an INVITE message to a remote SIP gateway on the outbound side. The Call Trace below is an INVITE/Offer message from the IMG 2020 to a remote gateway. The m= line shows that it is an audio call and that the RTP Data is encrypted using SRTP. This is displayed as RTP/SAVP. Below the m= line, the three cryptosuites being offered are F8_128_HMAC_SHA1_80, AES_CM_128_HMAC_SHA1_32, and AES_CM_128_HMAC_SHA1_80. Once the remote gateway receives the offer, it will respond with a 183 message displaying which cryptosuites are configured on the remote gateway. The call trace below displays the initial INVITE/Offer sent from the IMG 2020.