Creating A Hunt Group Service - Patton electronics SmartNode Series Software Configuration Manual

SmartWare Software Configuration Guide 33 • Call router configuration

Creating a hunt group service

A hunt group service hunts an incoming call to multiple interfaces. Figure 66 shows an example scenario where
a call from a SIP interface is first processed by several tables. The second table decides that the call must be for-
warded to the PSTN. The device is connected to the PSTN over four BRIs, which are bound to the context CS
interfaces IF-BRI0 up to IF-BRI3. All four ISDN interfaces lead to the same provider. Since the call router
does not know the load on the BRIs, it has to be able to try BRI0 and, if BRI0 already serves two calls, use
BRI1, and so on.
Figure 66. Hunt group service
The hunt group service accepts a call routed to it by a routing table or directly from an interface and creates
another call that is offered to one of the configured destination interfaces.
The interface tried first (IF-BRI0) may drop the call telling the service that the interface has no resources to
handle the call (e.g. no circuit channel available). Note that only the call between the hunt group and the des-
tination interface is dropped, while the original call between the SIP interface and the hunt group service
remains connected.
The hunt group then decides to try the next destination (IF-BRI1), which in turn also drops the call due to
unavailable resources. In our example the hunt group then tries the third and eventually the fourth destination.
When an interface accepts a call, the interface hunting is complete and the hunt group service merges the orig-
inal with the new call to the interface that accepted the call.
You can influence the algorithm of the hunt group by several configuration commands. You can specify
whether the hunt group shall always start with the same destination interface or whether it shall immediately
try the next one in a round-robin fashion. This is called cyclic operation mode.
Call router configuration task list 397