Bandwidth Clarification Question


  • So I'm going through the planning guide and looking at Chapter 3 in particular and I have some questions to clarify exactly how I should use the number to determine maximum bandwidth.

    So at the end of the bandwidth section is a table that gives information such as Typical, Max and Max with FEC.  I understand that I should use the max numbers.  The guide also gives me some information like that the bandwidth is only one-way audio.  Video is two-way where both endpoints send/receive.

    So the table gives items like Audio (Wideband) is 62 Kbps (91 w/ FEC), Video 260 Kbps, etc.

    So, the questions:

    1. Should the peer to peer audio max be 62 Kbps or 124 Kbps?  I would think since the document says it's one-way audio and people could both be talking at the same time, the number would be 124 Kbps.  But if I use the capacity planner and put in 2 users, it gives me back 62 Kbps.  So should I assume that in a peer to peer call, I only need one stream.

    2. Video seems like it should be 520 as a no-brainer, but again the capacity calculator gives me the lower - one stream only.

    3. Lastly, when does FEC kick in?  In the docs, I can only find "when packet loss occurs".  Is there a specific number (because I could literally seeing it happening to some degree on almost every call) or does it have to reach a particular threshold?



    • Moved by Noya LauModerator Friday, February 17, 2012 6:47 AM (From:Planning and Deployment)
    Tuesday, February 14, 2012 4:19 AM


  • Hi Chuck,

    The network bandwidth numbers in those tables represent one-way traffic only and include 5 Kbps for RTCP traffic overhead for each stream. For video the maximum video bit rate is used for computing the maximum stream.

    The recommendations created by the calculator are for planning purposes only. Actual load simulation is required to ensure that Lync Server 2010 is adequately provisioned. To perform stress testing under a simulated load, use the Lync Server 2010 Stress and Performance Tool.

    Noya Liu

    TechNet Community Support

    Friday, February 17, 2012 7:12 AM