Core Issue

Cisco IOS  needs to be able to perform a graceful (or forced) shutdown of VoIP call processing on a gateway router while leaving other router functions running normally. Graceful is defined as leaving existing calls up, but preventing new ones from being accepted or terminated on the router. Forced shutdown means all existing calls are immediately cleared and no new ones are accepted.

Resolution

Use the new Cisco IOS Software Release 12.3 feature called Gateway Shutdown Control.

Cisco IOS Software Release 12.3 has several new commands that allow all or selected VoIP processing to be stopped, while normal routing functions remain unaffected.

In router configuration mode, refer to:

voice service voip
     shutdown (forced)

The forced keyword stops all call processing immediately. The router can be returned to normal call processing by removing these commands:

voice service voip 
   no shutdown

Call processing can be selectively shutdown based on Signalling Protocol.  This example shows a Session Initiation Protocol (SIP) call service being shutdown on a Cisco gateway:

voice service voip
sip
call service stop

This example shows an H.323 call service being re-enabled on a Cisco gateway:

voice service voip
 h323
 no call service stop

For additional information on this feature, refer to Gateway  Codec Order Preservation and Shutdown Control .