Hung-ying Tyan 233718c3c5 Start keepalive process for the caller of a SIP call
so that the callee can send signals (on-hold or bye) back to the caller.
Without the keepalive, the NAT port for the caller will be timed out during the
call. And the signals will be dropped by the NAT device.

Change-Id: I21848d73469045b2ed9e7281556ab184c594c362
2011-06-27 19:33:24 +08:00
..