CAC- drop a call

[Ian Jones]

if I'm using CAC and the BW for the site is all used up- if someone wants to make a emergency services call - can CUCM drop one of the other calls to allow this one through ?

[Roger Kallberg]

Yes you can use MLPP to achieve this.

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[Jonathan Schulenberg]

Cisco specifically advises against using MLPP for this purpose.

Do not use the multilevel precedence and preemption (MLPP) feature to assign higher priority to emergency calls. An emergency-related call might not appear as such to the IP Telephony system, and you would risk terminating an existing emergency call to place another call to the main emergency service routing number. For example, an emergency situation might prompt someone to place a call to a regular ten-digit number to reach a medical professional. Preemption of this call would abort the ongoing emergency communication and could delay handling of the emergency. Also, incoming calls from emergency service personnel would be at risk of preemption by MLPP.

http://www.cisco.com/en/US/docs/voice_ip_comm/cucm/srnd/8x/dialplan.html

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[Roger Kallberg]

Well that might be the case, but afaik this is the only option there is to do what is asked for. If you have any other ideas please feel free to share. With a proper designed dial plan you should be able to take care of all calls to an emergency number, ie you should if you go down the path of using MLPP to give emergency calls a higher precedence see to it that all numbers deemed to be of that class are matched and given the proper precedence level. That should take care of the first concern raised in the SRND, the second option might be harder to do anything about. One option might be to use the route by calling party feature on translation patterns introduced in CM8, but that require you to know the calling number for any out dial call from an emergency service and that might not always be the case since that might be presented as a restricted caller id.

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