Unless I'm missing something, the ending is... weird?<p>> But with SIP/TCP, the re-registration storm can be substantial, and disruptive.<p>Why would the endpoints reregister? We can do TCP failover already by replicating connection state between SBCs. It's complicated, but should work (almost?) all the time with mostly idle connections.<p>Also, the "use TCP to avoid fragmentation" was in the RFC for what... 2 decades now? This was really frustrating to me when working with VoIP. There's no SIP standard: there's Linksys SIP, there's Avaya SIP, there's MS SIP, ... One will be UDP only, one TCP only, one will crash on fragments, another will have really low default MTU.