HP Survivable Branch Communication zl Module powered by Microsoft Lync Planning and Design Guide 2011-02

2-16
Design Considerations
Planning Call Capacity
Table 2-14. Estimate WAN Bandwidth Requirements (Example)
Although it is possible that the peak usage time for remote Lync calls will not
overlap with the peak usage time for remote PSTN calls, you add the two
values together to ensure adequate bandwidth. Therefore, this site would need
about 5.4 Mbps on the WAN connection to handle the call load (beyond
whatever bandwidth is required for other functions).
Considerations for Audio and Video Web Conferencing
If your solution includes audio and video conferencing, you must also plan
adequate bandwidth for those applications.
The process is much the same as estimating bandwidth for calls. First, if
possible, use records from an existing solution to find the number of simulta-
neous conferences of each type. Otherwise, make your best estimate at the
number. Note that all conferences are routed through the data center Lync
Server pool. Therefore, each conference consumes WAN bandwidth.
After estimating the number of concurrent conference users, multiply that
number by either the typical or maximum bandwidth required for the type of
conference. You must ensure that the WAN connections (and individual
endpoint connections) provide adequate bandwidth.
Table 2-15 indicates Microsoft’s recommendations for bandwidth for various
features (from the Microsoft planning guide for Lync requirements and the
guide for Enterprise Voice). Note that you must add features together for some
conferences. For example, a video conference might include RoundTable,
audio, and video components.
Call Type My Estimate for
Required Bandwidth
My Number of
Concurrent Calls
Total Estimated
Bandwidth
Remote peer-to-
peer calls
X = 39.8 Kbps E = 90 E*X = 3582 Kbps
Remote PSTN
calls
Y = 60 Kbps F = 30 F*Y = 1800 Kbps