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

3-7
Ready the Data Center for an SBM Deployment
Add the Survivable Branch to the Lync Server Topology
Configure Media Bypass (Recommended)
It is recommended that you configure Media Bypass for the SBM’s site.
Otherwise, you might not be able to reach the maximum of 120 PSTN calls, or
the call quality might suffer. See “Media Bypass” on page 2-17 for an overview
of this feature.
You enable Media Bypass from the Lync Server Control Panel. You can enable
it globally or for certain traffic only, as determined by site and region config-
uration. With the first option, Lync applies Media Bypass to all calls. This
option provides a simple setup but is not suitable for most environments in
which some calls should not use Media Bypass.
With the second option, Media Bypass automatically applies to only those calls
that are assigned the same bypass ID as the PSTN gateway. Lync automatically
assigns bypass IDs to devices such that all devices with the same ID are
connected by higher-bandwidth links that can support the higher-bandwidth
G.711-encoded traffic.
More precisely, Lync assigns bypass IDs based on region, site, and subnet
configuration as follows:
■ Each region is assigned a unique ID.
■ Each site in the region that is connected to the region’s central site without
bandwidth constraints is assigned the region ID.
■ Each site in the region that is connected to the region’s central site with
bandwidth constraints is assigned its own unique ID.
■ Each subnet that is associated with a site is assigned the site’s ID (which
might be the region ID or a unique ID for that site, as explained above).
Therefore, to ensure that Media Bypass applies to the SBM’s traffic, you must
perform the following:
1. If the region does not already exist, create a region associated with the
SBM’s parent central site.
2. Define a site for the SBM’s branch site in the Lync Server Control Panel
Network Configuration tab. Associate the site with its parent site’s region.
3. Associate all of the subnets at the branch site with this site.