TD 92326GB
2009-03-10 / Ver. E
Installation and Operation Manual
VoIP Gateway
144
21
Considerations on the Configuration of Call Routing
Your VoIP Gateway's gatekeeper is responsible for call routing. It is controlled by “routes”.
Note:
These are voice routes, not to be mistaken with the data or IP routes.
21.1 Routes
Each route defines a permitted path for a call, from the interface where the call arrives, to
the interface from which the call departs. The interfaces concerned can either be an ISDN
interface or a VoIP interface.
Figure 124. Unidirectional routes
A route is always defined for one call direction only. Two routes are thus necessary for
bidirectional calls (one for each direction).
Routes define call routing within a single VoIP Gateway. If a call is to be switched via two
VoIP Gateways a separate route is required in each VoIP Gateway. Four routes are then
required in total, for bidirectional calls.
shows a scenario in which calls are switched via the Gatekeeper between a
VoIP client connected to VoIP Gateway A and the ISDN network connected to VoIP
Gateway B.
Figure 125. Routes via 2 VoIP Gateways
The type of call is of no relevance to call switching. In principle, any call can be forwarded
to any given interface. For instance: For a call from a remote VoIP Gateway to your ISDN-
telephone, an incoming call on a Gatekeeper interface of the VoIP Gateway is put through
to the ISDN-interface to which your ISDN-telephone is connected.
Calls from different interfaces are often handled in the same way. That is why a number of
interfaces can be specified as permitted sources for a route.
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