SIP Trunking Deployment Overview


Topic Last Modified: 2010-11-08

Before you can deploy a SIP trunk, you and your service provider must exchange some basic connection information about your respective SIP trunk endpoints.

Get the following information for each ITSP gateway you will connect to:

  • IP address

  • FQDN


The service provider may ask you to connect to more than one ITSP gateway. In that case, you must configure a connection between each ITSP gateway and each Mediation Server in your pool.

The information you give to your service provider depends on your SIP trunk connection type:

  • For MPLS or private network connections, give the ITSP the publicly routable IP Address of the router in your perimeter network (also known as demilitarized zone, DMZ, and screened subnet). Verify that the gateway or Session Border Controller at the ITSP can reach this address. Also give the ITSP the FQDN of your server pool.

  • For VPN connections, give the ITSP the IP address of your VPN server.

Certificate Considerations

To determine whether you need a certificate for SIP trunking, check with your ITSP about protocol support:

  1. If your ITSP supports TCP only, you do not need a certificate.

  2. If your ITSP supports TLS, the ITSP must provide you with a certificate.


SIP works in conjunction with RTP or SRTP, the protocols that manage the actual voice data in VoIP calls.

Deployment Process

To implement the Lync Server 2010 side of the SIP trunk connection, follow these steps:

  1. Using the Lync Server Topology Builder, create and configure the SIP domain topology. For details, see “Define and Configure a Topology in Topology Builder” in the Deployment documentation.

  2. Using the Lync Server Control Panel, configure voice routing for the new SIP domain. For details, see “Configuring Trunks and Translation Rules” in the Deployment documentation.

  3. Test connectivity using the Test-CsPstnOutboundCall cmdlet. For details, see the Lync Server Management Shell documentation or Help for Lync Server Management Shell.