Hunt Groups

Hunt Groups

Hunt group is a term that is used to describe a group of Private Branch Exchange (PBX) or IP-PBX resources or extension numbers that are shared by users.

Hunt groups are used to efficiently distribute calls into or out of a given business unit. For example, a PBX or IP-PBX might be configured to have 10 extension numbers for the sales department. The 10 sales extension numbers would be configured as one hunt group. In a PBX or IP-PBX, hunt groups are used to efficiently locate an open line, extension, or channel when an incoming call is received. In a telephony network a hunt group is defined as a set of extension numbers that are grouped as a single logical unit. When an incoming call is received, the PBX or IP-PBX uses the hunt group or group of extensions that are defined to "hunt" for an available or open line, extension, or channel that can be used to receive the call.

There are multiple algorithms or methods that have been created to be used by a PBX or IP-PBX to define how the open line, extension, or channel will be located. These include:

• Round robin
• Most idle
• Start with lowest number

Creating and defining a hunt group in a PBX or IP-PBX minimizes the chance that a caller who places an incoming call will receive a busy signal when the call is received.

Unified Messaging Hunt Groups

Unified Messaging hunt groups are critical to the operation of the Unified Messaging system. The Unified Messaging hunt group is a logical representation of an existing PBX or IP-PBX hunt group. Unified Messaging hunt groups act as a connection or link between the Unified Messaging IP gateway and the Unified Messaging dial plan. Therefore, a single Unified Messaging hunt group must be associated with at least one Unfied Messaging IP gateway and one Unified Messaging dial plan.

Unified Messaging hunt groups are used to locate the PBX or IP-PBX hunt group from which the incoming call was received. A pilot number that is defined for a hunt group in the PBX or IP-PBX must also be defined within the Unified Messaging hunt group. The pilot number is used to match the information presented for incoming calls through the Session Initiation Protocol (SIP) signaling message information on the message. The pilot number enables the Unified Messaging server to interpret the call together with the correct dial plan so that the call can be routed correctly. The absence of a hunt group prevents the Unified Messaging server from knowing the origin or location of the incoming call. It is very important to configure the Unified Messaging hunt groups correctly, because incoming calls that do not correctly match the pilot number defined on the Unified Messaging hunt group will not be answered and incoming call routing will fail.

When you create a Unified Messaging hunt group, you are enabling all Unified Messaging servers that are specified within the Unified Messaging dial plan to communicate with an IP/Voice over IP (VoIP) gateway. If you delete the Unified Messaging hunt group, the associated IP/VoIP gateway will no longer service calls with the specified pilot number. If the IP/VoIP gateway is left without remaining Unified Messaging hunt groups, the IP/VoIP gateway will not be able to handle incoming calls.