A look into Instant Messaging using SIP

In vanilla RFC3261 SIP, a UA can only send a REGISTER request to a SIP Registrar. It can’t go via any intermediary proxies. That’s obviously a bit of a problem, as we build out our network we might have a series of load balancers that send traffic to a pool of Registrars, but according to […]
SIP Register status, expires and why it’s often misunderstood.