RFC-3261 doesn't talk much about TimerC and when it fires. I understand the importance of TimerC in forking scenarios.
Does TimerC have any role in regular SIP call?
RFC-3261 doesn't talk much about TimerC and when it fires. I understand the importance of TimerC in forking scenarios.
Does TimerC have any role in regular SIP call?
Correct. Only Proxies use Timer C. Timer C is the proxy INVITE transaction timeout. It is used to check if a proxied INVITE request never generates a final response. The Timer C MUST be set for each client transaction when an INVITE request is proxied ie each URI you forward the SIP INVITE to after receiving the initial INVITE.