Nailed-Up Connection

[Approved]

SIP Server can provide a persistent SIP session for agents who require a dedicated connection to the contact center—typically, for TDM agents who are dialing in to the contact center from the PSTN. The agent can make calls, wait for calls, and send or accept transfers while maintaining the current SIP connection to the contact center. If a call to the agent DN is released by either the caller or by an agent 3pcc request (TReleaseCall, TSingleStepTransferCall, or TCompleteTransfer), SIP Server does not end the SIP session; instead, it parks the agent DN on the predefined gcti::park device. The session is released only after the agent hangs up the phone (1pcc release call).

Important

In Business Continuity deployments, any DN with a statically configured contact must use dr-forward set to no-agent. In practical terms, such a DN is commonly used for a “remote agent”, often in conjunction with the nailed-up connection.

How SIP Server Establishes the Nailed-Up Connection

SIP Server can set up the nailed-up connection between the remote TDM agent and the contact center using the following methods:

• SIP Server calls the agent to start a session—SIP Server sends the call to a remote TDM agent configured for the nailed-up feature. This applies to the first transfer to the agent, where the initial nailed-up session starts. When the caller releases the call or the agent releases the call using 3pcc, SIP Server parks the agent on Stream Manager, keeping the connection for the call leg to the nailed-up connection.
• The agent calls the contact center to start a session—The remote TDM agent (configured for the nailed-up feature) initiates a call (1pcc) to the contact center.

SIP Server Calls the Agent to Start a Session

The basic call flow when SIP Server first calls an agent who is configured for the nailed-up feature is as follows:

1. SIP Server receives a customer call, which the Universal Routing Server then processes.
2. After qualification and queuing, the routing strategy selects the agent who will handle the call.
3. SIP Server contacts the agent as it would for any remote TDM extension (SIP Server does not yet consider the agent to be nailed-up).
4. At the end of the call, when the agent requests to release the call through the Agent Desktop (a 3pcc TReleaseCall), SIP Server does not disconnect the call leg to the nailed-up connection but, instead, parks the agent on the predefined gcti::park device. At this point, the agent is considered to be nailed-up. Stream Manager applies a silent treatment while the nailed-up connection is maintained.

In Business Continuity deployments, SIP Server applies the following “Call Delivery” logic when establishing the initial call to a DN with a statically configured contact:

1. If the first SIP Server to handle the call determines an agent is locally logged in and using the DN, this SIP Server delivers the call directly to the DN.
2. Otherwise, the first SIP Server forwards the call to the second SIP Server on the alternate site, using the inter-site Trunk DN and ISCC. The second SIP Server delivers the call to the DN, regardless of whether any agent is logged in and using the DN or not.

Important

Carefully consider this behavior. This could result in high telephone connection charges, if, for example, DNs and data centers are distributed across different countries.

Agent Calls the Contact Center to Start a Session

The basic call flow when a remote TDM agent who is configured for the nailed-up feature is as follows:

1. A call from the remote agent arrives at the contact center on a Routing Point DN.
2. A short treatment is applied, and URS issues a TRouteCall to the predefined gcti::park device (RouteType=Unknown; OtherDN=’gcti::park’).
3. SIP Server parks the agent on the gcti::park device, keeping the call leg to the agent connected. At this point, the agent is considered to be nailed-up. Media Server applies a silent treatment while the nailed-up connection is maintained.

In Business Continuity deployments, each data center should have a unique routing point, which allows an agent to connect to their preferred data center based on which routing point they contact.

Feature Configuration

On the Trunk DN that represents the gateway that is used to contact the remote agent, specify the following option in the TServer section:

• refer-enabled—Set to false.

On the ACD Position or Extension DN for the agent, specify the following options:

• line-type—Set this option to 1.
• refer-enabled—Set this option to false.
• dual-dialog-enabled—Set this to false.
• reject-call-notready—Set this option to true (recommended, not mandatory).
• sip-cti-control—Ensure that this option is not configured.

To enable automatic disconnection of the agent from the nailed-up connection on agent logout, in the TServer section of the SIP Server Application, configure the following option:

• drop-nailedup-on-logout—Set this to true.

  
  

  Important

  If enabled, SIP Server can only establish the nailed-up connection if the agent is logged in.

For Business Continuity deployments, set dr-forward to no-agent. See Basic Deployment for details.

Feature Limitations

• Consultation calls for nailed-up DNs are supported in single dialog mode only.

• If an agent with the nailed-up connection is participating in the first call before it was ever parked, SIP Server cannot park this agent if the call is released before it is established. For example, if the agent with the nailed-up connection initiates a call and releases it while the call is ringing, or if the agent with the nailed-up connection completes a two-step transfer in ringing state. To avoid this, the agent should call the call center to get parked first.