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Hunt Groups in Standalone Deployments

SIP Server supports the Hunt Groups feature as a type of call coverage to distribute incoming calls to a statically configured group of extensions. The Hunt Group call distribution strategy (sequential or parallel) controls how a call is propagated to one or to all extensions within the group.

Note: Starting with version 8.1.101.49, Hunt Groups with the parallel distribution strategy (simultaneous ringing) are supported in Business Continuity deployments. See the SIP Server 8.1 High-Availability Deployment Guide for details.

Hunt Group members are Extension DNs or ACD Position DNs listed in the hg-members option. In contrast to the typical Genesys call distribution using a routing point, URS/ORS and Stat Server, the Hunt Group does not rely on or require any login. Hunt Group distribution does take into account the status of each DN, and will distribute calls only to those DNs which meet the following criteria:

  • DN must be in-service
  • DN must be idle (not in a call)
  • DN must not have DND or Call Forwarding set on SIP Server

In a sequential call distribution, SIP Server selects one of the available Hunt Group members as a target for the call distribution. If the Hunt Group member answers the call, the call is diverted from the Hunt Group and the distribution is complete. If the call is rejected by the Hunt Group member, or not answered within a specified period of time (hg-noanswer-timeout), SIP Server selects the next available Hunt Group member for a call distribution. Depending on the configuration, SIP Server uses one of the following strategies for Hunt Group member selection:

  • Linear hunting. SIP Server always distributes the calls to the first Hunt Group member, then to the second, to the third, and so on. Hunting stops at the last Hunt Group member.
  • Circular hunting. SIP Server distributes the calls in a round-robin fashion. If a call was previously delivered to the first Hunt Group member, the next call SIP Server distributes to the second member, and so on. The succession throughout each of the Hunt Group members continues even if one of the previous members becomes available. When a list of Hunt Group members is exhausted, the hunting starts over at the first member. Hunting stops at the Hunt Group member who answered the previous call. That is, SIP Server makes only one circle through the Hunt Group member list.

In a parallel call distribution, when any Hunt Group member answers the call, the call is diverted from the Hunt Group and SIP dialogs with the non-answered Hunt Group members are dropped. This SIP Server behavior is known as divert-on-answer and works differently from the usual queue distribution enabled by the divert-on-ringing configuration option. For the Hunt Groups feature, you do not need to set the divert-on-ringing option to false. The hg-type option triggers that by default.

The call distribution is considered unsuccessful if:

  • None of the Hunt Group members answers the call.
  • There are no available Hunt Group members during the specified period of time (hg-queue-timeout).
  • The number of queued calls on the Hunt Group exceeds the specified limit (hg-queue-limit).

The unanswered call is distributed to the default destination if it is configured; otherwise the call is released.

It is not recommended to use Extension or ACD Position as the default-dn destination for the Hunt Group to avoid call overflow at that DN. A Routing Point DN should be used instead.

Call forward redirection from a SIP endpoint or from an agent desktop application like Interaction Workspace will be ignored for calls distributed from a Hunt Group. Calls distributed by the Hunt Group to a member will not be diverted to the member's mailbox if there is no answer.

Feature Configuration

On a DN of type ACD Queue, specify the following configuration options in the TServer section:

  • hg-type—Specify the type of Hunt Group algorithm that is used to deliver calls to Hunt Group members.
  • hg-members—Specify members of the Hunt Group by listing DNs separated by a comma.
  • hg-noanswer-timeout—Set the period of time that a call distributed to the members waits to be answered by a member.
  • hg-queue-limit—Set a maximum number of calls that can be queued on the Hunt Group at the same time.
  • hg-queue-timeout—Set the period of time that a call can remain in the Hunt Group (while all Hunt Group members are not reachable) before being sent to Hunt Group members.
  • hg-busy-timeout—Set the period of time during which SIP Server will not distribute calls to the Hunt Group member’s device after it answers with an error.
  • default-dn—(Optional) Specifies the default destination where a call is distributed if one of the following conditions occurs:
    • hg-noanswer-timeout expires
    • hg-queue-timeout expires
    • hg-queue-limit is exceeded
    • no correct Hunt Group members are defined
  • If the Hunt Group does not have the default-dn option defined, SIP Server uses the Application-level default-dn instead.

Configuration Options

This section includes only new and modified Hunt Group configuration options. See the Framework 8.1 SIP Server Deployment Guide for a complete list of Hunt Group configuration options.

hg-type

Default Value: No default value
Valid Values: fork, linear, circular
Changes Take Effect: For next call distribution

Specifies the type of Hunt Group algorithm that is used to deliver calls to Hunt Group members, as follows:

  • fork–Parallel distribution strategy (forking)
  • linear–Sequential distribution strategy, linear hunting
  • circular–Sequential distribution strategy, circular hunting

hg-noanswer-timeout

Default Value: 0
Valid Values: 0–600
Changes Take Effect: For the next call

For a parallel call distribution, this option specifies the period of time, in seconds, that a non-answered call remains in a Hunt Group before SIP Server either redirects the call to the default-dn destination (if configured) or rejects it.

For a sequential call distribution, this option specifies the period of time, in seconds, that SIP Server allows for a Hunt Group member to answer a call before SIP Server redirects the call to another available Hunt Group member. If the call is not answered, SIP Server either redirects the call to the default-dn destination (if configured) or rejects it.

If set to 0, the call remains in ringing state until it is answered by the destination or dropped by the caller.

hg-queue-limit

Default Value: 0
Valid Values: 0–20
Changes Take Effect: For the next call

Specifies the maximum number of calls that can be queued at the Hunt Group. When the limit is reached, a new call is either redirected to the default-dn destination (if configured) or rejected.

If set to 0, the number of calls in the queue is unlimited.

hg-queue-timeout

Default Value: 30
Valid Values: 0–6000
Changes Take Effect: For the next call

Specifies the period of time, in seconds, that a call is queued on the Hunt Group waiting for processing. When the time period is reached, the call is either redirected to the default-dn destination (if configured) or rejected. If set to 0, the call remains in the queue until all previous call processing is finished, or the call is dropped by the caller.

Feature Limitations

  • Hunt Groups are not compatible with SIP Server’s Early Media feature. A call to a Hunt Group will be immediately connected, which typically results in the caller being charged before the call is answered by an agent.
  • Predictive calls (initiated by the TMakePredictiveCall request) are not supported. If a predictive call arrives at a Hunt Group, it will be rejected by the Hunt Group.
  • Hunt group is not supported in deployment with IMS (double-triggering).
  • A DN with nailed-up connection (line-type=3) must not be a member of a Hunt Group.
  • DNs of the Hunt Group members must be located on the same switch as the Hunt Group.
  • Calls distributed from a Hunt Group will not invoke the external Feature Server dial plan.
  • It is not possible to use the Call Pickup feature to answer ringing calls for members of the Hunt Group. An attempt by a Hunt Group member to answer a call using the Call Pickup feature will be rejected.
  • 1pcc semi-attended, 3pcc semi-attended, and mute transfers to a Hunt Group destination are not supported.
This page was last modified on May 31, 2016, at 15:41.

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