Given half a chance, I am always open to punt The SIP School as probably the best starting point for learning SIP out there. I took this course some years ago, and was recently able to convince our management to get our whole voice team to complete the training. It has really skilled up our team and made us a force to be reckoned within our local market. If you want to learn SIP, look no further. I’ve said it loads of times, this was without a doubt the key to my CCIE Collaboration success. Before you ask, I have no affiliation to the SIP School whatsoever – am just a very, very satisfied customer!
That being said, my main motivation for suggesting this training material is that the course, although covering Core SIP and other topics incredibly well, is, by design, heavily influenced by the IETF standards documentation. At the time of studying for the SSCA exam, I took the opportunity to do a detailed study of the RFCs that each section referenced. To me, it is very important as a VoIP Engineer to have a strong understanding of RFC Compliance – particularly for SIP!
That being said, I only recently came across RFC 5411. I can’t believe that in the last 5 years I’ve missed this! This is absolutely the coolest IETF RFC for VoIP ever. Unsurprisingly, this was written by Jonathan Rosenburg.
This is really a great starting point for working through the long list of RFCs that cover standard-based SIP (a term that can only ever be used loosely, haha). Although there have been several key RFCs post-2009, this is an excellent starting point for even a seasoned SIP professional. I particularly like how Jonathan has broken down this list functionally. If you’re anything like me, you’ll soon find yourself deep down the rabbit hole! And it definitely goes deep 🙂
I am particularly fond of these as well:
For something more Cisco-centric, this is a great read on how Cisco has recently endeavoured to remain RFC-compliant:
Happy reading. Please ping me to add to this list!