350-801 Question #383: Real Exam Question with Answer & Explanation

Question

Location-based call admission control is used in Cisco UCM to control the amount of bandwidth allowed between predefined locations. What must be considered when calculating the number of calls that can be made?

Options

• AA limit of 900 kb is the total amount of bandwidth used for the sum of the media and signaling in
• BA limit of 900 kb Is the total amount of bandwidth used for the sum of calls of the defined codec
• CA limit of 900 kb is the total amount of bandwidth used for the sum of calls. The use of
• DA limit of 900 kb is the total amount of actual used RTP traffic so the oversubscription can be

Explanation

When calculating the number of calls for location-based CAC, a bandwidth limit represents the total aggregate bandwidth used for the sum of all concurrent calls traversing the link between locations.

Approach. Location-based Call Admission Control (CAC) manages the aggregate bandwidth consumed by all active media streams between two locations. The bandwidth limit, such as 900 kb, is the total amount available for the sum of all concurrent calls, irrespective of the specific codec or type of call, which are then individually factored into the total.

Common mistakes.

• A. Location-based CAC primarily controls media bandwidth; signaling bandwidth is generally insignificant and not typically included in the explicit CAC bandwidth calculations.
• B. The 900 kb limit represents the total aggregate bandwidth for all calls, which may use various codecs, not just for the sum of calls utilizing a single defined codec.
• D. CAC calculations use the configured bandwidth for codecs (including overhead), which are estimations, rather than the fluctuating 'actual used RTP traffic,' to make admission decisions reliably.

Concept tested. Location-based CAC bandwidth calculation

Reference. https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/srnd/collab12/collab12/cac.html

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