Gradwell trunks can be used with Microsoft Lync, however in order to work we need to use Session Border Controllers (SBCs). This is because SIP usually transfers datagrams using UDP. However, Lync uses TCP as the transmission method for SIP messages. The SBCs convert traffic from UDP to TCP (or vice versa) at the edge of our network.
To use Gradwell services with a Lync deployment, you need to purchase licences to use the SBCs and configure your trunk to use the SBCs.
Purchasing SBC licences
After you have purchased your Gradwell trunk service, login to the VoIP control panel and click on Packages in the top menu.
Select to add a new package and then select SBC Licence from the services list. You will be taken through the purchase process for the licences to be added to your account. You need to purchase a licence for each concurrent call that you expect to have.
Applying SBC licences to your outbound trunk
To apply the licence to your outbound trunk, click on SIP Outbound from the top menu.
Enter the IP address of your PBX, and using the SBC Profile dropdown select Lync. This will notify our SBCs to expect SIP traffic from your PBX.
Configuring your trunk
On your trunk settings, please ensure that you configure sbc.voip-system.net as the next hop after your network.
Please note that standard Gradwell trunks use sip.trunk.gradwell.com. Please do not configure this on your Lync deployment as your traffic will not go via our SBCs and calls will fail.