An outbound call is in progress through a Cisco Unified Border Element using G729r8 codec.
And it is dropped after 60 minutes.
Root cause analysis revealed that ITSP signaled a codec change to G711u.
Which two Cisco Unified Border Element configuration changes will prevent this problem from happening again? (Choose two)
Click on the arrows to vote for the correct answer
A. B. C. D. E. F.BD.
The root cause of the issue is that the ITSP signaled a codec change to G711u during the outbound call, which caused the call to be dropped after 60 minutes. To prevent this problem from happening again, we need to make some configuration changes on the Cisco Unified Border Element (CUBE).
A. Configure the voice-class sip midcall-signaling block command on the outbound dial peer.
This command is used to block any mid-call signaling messages that may change the codec. However, if the ITSP sends a codec change message during the call, the call will still be dropped. Therefore, this command alone may not be sufficient to prevent the issue from happening again.
B. Configure the midcall-signaling preserve-codec under voice service voip.
This command is used to preserve the current codec during a call if a codec change message is received. This means that if the ITSP sends a codec change message during the call, the CUBE will ignore it and continue to use the current codec. This command is a global configuration and will apply to all outbound calls.
C. Configure the voice class-codec command with G711u and G729r8 codecs on the outbound dial peer.
This command is used to specify the codecs that are allowed on the outbound dial peer. By specifying both G711u and G729r8 codecs, we ensure that the call will continue to use one of these codecs even if the ITSP sends a codec change message during the call.
D. Configure the voice-class sip midcall-signaling preserve-codec command on the outbound dial peer.
This command is similar to option B, but it applies only to the specific outbound dial peer. This means that if a codec change message is received on this dial peer, the CUBE will ignore it and continue to use the current codec.
E. Configure the midcall-signaling preserve-codec command under each outbound ITSP dial peer.
This command is similar to option B, but it applies only to the specific outbound ITSP dial peer. This means that if a codec change message is received on this ITSP dial peer, the CUBE will ignore it and continue to use the current codec.
F. Configure the midcall-signaling passthru media-change command under voice service voip.
This command is used to allow mid-call codec changes if the new codec is supported by both endpoints. However, this command may not be suitable in this case since the G711u codec is not supported by the endpoint.
Therefore, options B and C would be the best choices to prevent the issue from happening again. Option B applies to all outbound calls, while option C specifies the codecs that are allowed on the outbound dial peer. However, option D or E may also be used instead of option B if we want to apply the configuration only to specific dial peers or ITSPs.