I am developing a SIP client. I understand SIP requests and SIP responses but, in SIP messages, how are the call id and branch tags generated? RFC3261 does not specify this.
Share
Sign Up to our social questions and Answers Engine to ask questions, answer people’s questions, and connect with other people.
Login to our social questions & Answers Engine to ask questions answer people’s questions & connect with other people.
Lost your password? Please enter your email address. You will receive a link and will create a new password via email.
Please briefly explain why you feel this question should be reported.
Please briefly explain why you feel this answer should be reported.
Please briefly explain why you feel this user should be reported.
I am developing a SIP client. I understand SIP requests and SIP responses but, in SIP messages, how are the call id and branch tags generated? RFC3261 does not specify this.
The Call-ID header value can be anything you want but does need to be unique in order to avoid requests getting classified as duplicates.
THe branch parameter on a Via header needs to start with the magic cookie value of z9hG4bK and must also be unique to avoid the request getting classified as a duplicate. For SIP Proxy’s wanting to do loop detection there is also the guideline in the RFC in section 16.6 point 8 which details factors to take when constructing the branch parameter value.