Active telephony call legs appear for non-existent calls in the output of show call active voice brief. The SPE Digital Signal Processor (DSP) associated with this call leg is not released, which may cause problems in the Cisco IOS VoIP gateway from processing calls once all DSPs are in use. The telephony call legs are in a connected state and there is no active IP call leg associated with the call.
The output of show spe command shows SPEs in an active (a) state with no call type associated with the call.
This is seen in a heavy load VoIP environment on Cisco AS5400 gateways. This may also relate to the use of TCL scripts during call processing and calls which disconnect with a non-normal call clearing (a non 0x10 cause code).This has been seen in an H.323 call environment but it is unclear if this may occur for Session Initiation Protocol (SIP) environments as well.
This issue is documented in Cisco bug ID CSCsb76266.
Once the call legs are in this state, the only known way to recover the SPE DSP resources is to reload the gateway.
In order to resolve this issue, upgrade the Cisco IOS Software Release to any one of these versions: