Patton electronic SmartNode 4110 Series manual Hunt group service

SmartWare Software Configuration Guide 40 • Call router configuration

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.

		Context
interface sip IF-SIP				interface isdn IF-BRI0
		Call Router
					interface isdn IF-BRI1
first routing table		routing table		route
a		i		route
b		j
c	route	k	route	route	interface isdn IF-BRI2
	execute
				hunt group
a	A			service
b	B			route	interface isdn IF-BRI3
mapping table

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.

You can specify a timeout after which the next destination interface is tried when there is no answer at all from the destination interface.

You can specify drop causes that trigger hunting for the next destination. All other causes (e.g. user busy) will drop the original call.

Call router configuration task list 498