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Cisco Bug: CSCuq85618 - IOS voice gateway crash due to Media Antitrombone

Last Modified

Sep 03, 2020

Products (16)

  • Cisco IOS
  • Cisco ASR 901-6CZ-F-D Router
  • Cisco ASR 901-6CZ-FS-D Router
  • Cisco ASR 901-4C-FT-D Router
  • Cisco ASR 901S-4SG-F-D Router
  • Cisco ASR 901S-2SG-F-AH Router
  • Cisco ASR 901-6CZ-F-A Router
  • Cisco ASR 901S-2SG-F-D Router
  • Cisco ASR 901-6CZ-FT-A Router
  • Cisco ASR 901-12C-FT-D Router
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Known Affected Releases


Description (partial)

A router configured as a voice gateway may unexpectedly crash and reload when a call leg is being torn down. This will typically exhibit itself either as a segmentation fault or a fatal alignment error in the CCSIP_SPI_CONTROL process, similar to the following:

Exception to IOS Thread:
Frame pointer 0x7F2BE5A5A640, PC = 0x7F2C48756219

UNIX-EXT-SIGNAL: Segmentation fault(11), Process = CCSIP_SPI_CONTROL
-Traceback= 1#08b65be3f4ae1c460ee5571211270cd0  :7F2C39A71000+ECE5219 :7F2C39A71000+ED1FD1C [omitted] 

Media antitrombone must be enabled on the router. This configuration would look similar to the following:

voice service voip
 media anti-trombone

This will happen while tearing down a call leg (e.g. call ends, call is transferred, etc). It occurs due to a timing problem internal to IOS, and so predicting if the crash will occur for a particular call is likely not feasible.
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