If you are encountering issues with using Gradwell trunks on your Lync deployment, the troubleshooting steps outlined below have been found to resolve most problems.
Please note that Gradwell only support the sending of calls to your platform, or accepting calls from it. We cannot assist with configuration of your deployment or any services.
If none of the steps below resolve your problems, contact Gradwell Support. We will be able to run traces from within our network to verify whether we are successfully sending or receiving a call from your Lync deployment.
Ensure that you have both an inbound and outbound SIP trunk package
If you are planning to both make and receive calls from your Lync deployment, please ensure that you have purchased both inbound and outbound SIP trunk services. If, for example, you only purchased inbound SIP trunks you will not be able to make an outbound call.
Check SBC licences have been purchased
Because Microsoft Lync uses TCP, yet standard SIP uses UDP, we need to use Session Border Controllers (SBCs) to convert TCP to UDP (or vice versa) on the edge of our network.
To use our SBCs, you need to purchase one SBC licence for each concurrent call you expect to have.
Check SBC licences have been applied onto your trunk
You need to inform our system that you will be sending traffic to our SBCs, which requires you to configure the trunk correctly in your Gradwell VoIP control panel. Use the following guides for assistance with purchasing SBC licences and correctly applying them to your trunk:
Check SIP URI formatting
Lync uses E.164 formatting for numbers, that is international format (e.g. +441225800123). If you are using an inbound trunk ensure that the trunk is configured to use E.164, otherwise we will send calls to you in the incorrect format
Check IP address
Ensure that you have configured the IP address of your Lync deployment correctly in the Gradwell VoIP control panel.
Check the configuration of the next hop from your deployment
Outbound calls from your network should be sent to sbc.voip-system.net. Calls routed to any other Gradwell hostname will not be routed via our SBCs and the call will fail.
Run a traceroute to sbc.voip-system.net from within your network to ensure that you can resolve it.
Generate a call trace from your system
If you can, trace a call from within your system. This is likely to show any error codes, as well as confirm that you are sending traffic to the correct address (or in the case of an inbound call, receiving the call from our system).