feature: VoIP in-depth: An introduction to the SIP protocol, Part 2 (Ars Technica)
In Part 1 of our SIP primer, I covered the SIP foundation layers starting from the message structure and ending with the SIP transactions. We saw how phone registrations and proxies could work using these layers. This second part completes the discussion by covering the way SIP defines calls, and in general, any type of communication. Naturally, this installment is built on the previous part ...
