This article describes how calls in and out work if a Hosted Lync customer uses voice services (Plus and Enterprise Plus licences).
Calls outside of the Lync organisation (i.e. those to and from external phone numbers) pass through various servers in order to work. At a high level, the system is setup as in the picture below:
An inbound call from the phone network comes into Gradwell's main VoIP network via a SIP trunk. Our system recognises that this is a call for a Lync user and forwards it to a Session Border Controller (SBC). The SBC is required because whereas our network uses the SIP standard of UDP for transmitting SIP messages, Lync uses TCP. The SBC converts converts any SIP packets as they pass through (and vice versa).
All messages are handed over to the Lync mediation server within our Hosted Lync setup. This will forward the call into the Lync system where the customer who uses that phone number will be worked out, and then the user or call group that uses the phone number that the inbound call is for. Finally, the call can be delivered to the customer as appropriate, or any call forwarding rules followed.
Outbound calls are handed from the Lync setup to the SBC, which forwards the call into our main VoIP network. Here the call will be checked for available credit, and whether the destination is allowed under the account's call barring settings. If the call is authorised, it will be forwarded via our upstream suppliers to the dialled party.
There are two billing points in the setup.
The Gradwell Cloud system (which hosts our Lync setup) charges the customer for services used (Lync licences) based on the rates you configure.
The Gradwell VoIP network calculates the charges for outbound calls.
In all cases, the customer needs to be active in both systems, with available credit make calls in the Gradwell VoIP system (some resellers may choose to disable credit control on a customer account, however this is at your own risk).
Invoices for services will be calculated and sent out automatically by the Cloud system. In order to calculate invoices for calls made, you will need to download the CDR data from the VoIP reseller control panel and input them into your invoicing platform.