Refer to the exhibit.
A user at BR1 is on a call to the PSTN through the PRI interface on the local H.323 gateway. The IP WAN has just failed and the call has been dropped.
What is causing the call to be dropped?
A.
The H.323 gateway has lost the D channel on the PRI.
B.
SRST hasn’t been configured on the BR1 gateway.
C.
The no h225 timeout keepalive command has not been configured on the gateway.
D.
The IP phone hasn’t registered with SRST.
As you can see in the question, the call has been stabilished before it has been dropped. If the call would never connected your presumption is , the gw has lost the D channel, but the call connected and then dropped. It means the H225 TCP sockets were closed and it was due to TCP timeout occurred on H225 channel and it can be solved setting no h225 timeout keepalive in h323 config -inside voice service voip configuration.
Letter C is corre