Bandwidth calculation in cisco call manager

Posted on 2009-04-22
Last Modified: 2012-05-06
This is a Cisco Call MANAGER Question.

Given the following how do I calculate number of audio and video calls between two locations?

From Region configuration:
Codec used G.729
Video call bandwidth=384kbps

From Location configuration:
Audio bandwidth=512kbps
video Bandwidth=768kbps


Question by:Abnel
    LVL 7

    Expert Comment

    G729 is about ~40k per call.  So, if you have 512k for audio, you can do 12 calls at any given moment.
    However, I see video is 384k (which is a common video setting per video conf), which is fine, but 768k is not enough for 2 streams because you need to factor in overhead (for multipoint sessions).  Use 420k or so for overhead per video stream.

    Author Comment


    I am a bit confused, thought  G.729  is 24kbps uncompressed, and 8kbps compressed. Can you explain me why you said 40? I do not have good knowledge with various CODECs.

    LVL 7

    Accepted Solution

    Aside from the voice payload, there are other elements for budgeting for voice packets.  In general, 40k is a fair budget for this codec.
    There are various formulas here:
    You'll see Ethernet bandwidth in the table all the way to the right.  I know there are various flavors of g729, but 40k is a fair estimate most people use.

    Author Closing Comment

    Thank you for your support, the link you provided is also very helpful,


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