Core Issue
This is the configured and expected call flow:
- Call a hunt pilot number that routes to a hunt list.
- The hunt list contains three line groups.
- The first line group is configured to broadcast the call to five IP phones. On no answer, the call rolls over to the second line group.
- The second line group is a single IP phone (an operator number). On no answer, the call rolls over to the final line group.
- The third line group contains voice mail ports to take the caller to voice mail to leave a message.
This occurs when calling the hunt pilot:
- The five IP phones in the first line group all ring.
- After a no answer timeout, the operator's IP phone rings.
- The call is disconnected.
Resolution
This is expected behavior. The call exceeds the T301 timer. This timer is the duration that a caller is in the alerting phase of the call (hearing ring back). The T301 timer is a cluster-wide Cisco CallManager service parameter, which should not be modified to change the behavior of hunt lists because it affects all phones.
To rule out voice mail problems, move the third line group (containing the voice mail ports) to the top of the hunt list. The call goes successfully to voice mail. Note: This problem is related to the time-out, not to the voice mail ports. The call would have the same behavior if it was forwarded to a normal extension.
For reference, the context-sensitive help in the Cisco CallManager 4.0 Administration pages provides this information on the T301 timer:
This parameter specifies an ISDN Layer 3 timer for
User (Call Delivered) ALERTING Received, Network (Call Received)
ALERTING Received.
For exact timer definitions, refer to the Q.931 specification.
This value should always be greater than the value specified
in the Forward No Answer Timer parameter;
if it is not, the call is not forwarded
and the caller receives a busy signal.
For information on Cisco CallManager service paramaters, refer to Service Parameters Configuration.
