SBM powered by Microsoft Lync™ Administrator's Guide 2011-11

A-27
Ready the Data Center for an SBM Deployment
Add the Survivable Branch to the Lync Server Topology
• If the SBM is using SIP trunking to forward PSTN calls, specify the
ITSP’s FQDN or IP address.
• If you are using SIP trunking primarily, but the SBM’s internal PSTN
gateway for backup, specify the ITSP’s FQDN or IP address for now.
15. Select the SIP Transport Protocol. It is recommended that you select TLS,
which provides encryption.
16. The Listening port for PSTN gateways field fills in automatically based on
the selected protocol. You can change this setting if you want, but you
must inform the technician installing the SBM, so he or she can specify
the same port. The default port in this wizard matches the default port in
the SBM Setup Wizard.
The transport protocol and listening port apply to calls as they move from the
SBM’s internal Mediation Gateway to its internal Media, or PSTN, gateway (1
in Figure A-23).
Note The default ports for an external gateway (such as an ITSP gateway) are 5067
or 5068.
Figure A-23. SIP Ports