SIP Delayed Media Outbound

The IMG 2020 supports both inbound and outbound delayed media. For information on inbound delayed media see SIP Delayed Media Inbound - 3PCC. SIP Delayed Media Outbound gives the IMG 2020 the ability to generate an outbound delayed media SIP call where the INVITE message generated does not contain an offer SDP. Negotiation will proceed once offer SDP is received from a far end provisional response or in final response. The IMG 2020 will either pass, release, or cancel the call. Below are the three scenarios supported.

Scenario 1

Open

• IMG 2020 generates an INVITE with No SDP (empty INVITE) and sends INVITE to Far End Gateway.

• The Far End Gateway responds with a 180 Ringing followed by a 200 OK with SDP (offer) in the response.

• The IMG 2020 and Far End Gateway negotiate the offer based on local capabilities.

• If negotiation is successful, the IMG 2020 sends the answer in an ACK message and the call is connected.

• If negotiation fails, IMG 2020 will reject the offer in the ACK by setting the port to 0 and release the call by sending a BYE. See call flows above.

Scenario 2

Open

• IMG 2020 generates an INVITE with No SDP (empty INVITE) and sends INVITE to Far End Gateway.

• Far End Gateway responds with a non-reliable 183 Session Progress or 180 Ringing with SDP (offer).

• IMG 2020 ignores this SDP since the SDP came in a non-reliable non failure 183 Session Progress message from the Gateway.

• The Gateway then sends the SDP in the 200 OK message. Since this is a reliable message, the IMG 2020 negotiates the offer based on local capabilities.

• If negotiation is successful the IMG 2020 sends the answer in an ACK to the gateway.

• If negotiation fails, the IMG 2020 shall reject the offer (SDP) in the ACK by setting the port to 0 and then release the call by sending a BYE message to the gateway. See call flow diagrams above.

Scenario 3

• IMG 2020 generates an INVITE with No SDP (empty INVITE) and sends INVITE to Far End Gateway.

• Far end Gateway responds with a reliable 183 Session Progress or 180 Ringing with offer (SDP).

• IMG 2020 negotiates the offer received in the reliable 183 Session Progress or 180 Ringing with offer (SDP) based on local capabilities.

• If negotiation is successful, the IMG 2020 will send answer in a PRACK.

• If negotiations fail, IMG 2020 releases the call by sending CANCEL.

Configuration Procedure

The procedure below explains how to configure the IMG 2020 for outbound delayed media. Before configuring the outbound delayed media feature, the IMG 2020 must have an initial configuration created on it. Follow the Basic Configurations procedure before proceeding onto configuring the IMG 2020 for delayed media.

Create an Signaling Gateway Profile (SGP) for Delayed Media Feature

• Right click on the Profiles object and select New SIP Profiles. The SIP Profiles object is a parent or container object. No configuration is needed here. Refer to the SIP Profiles topic for more information on this object.

• Right click on the SIP Profiles object and select New SIP Profile. The first profile that gets created is a Default SIP Profile and cannot be modified. Disregard this profile.

• Right click on the SIP Profiles object and select New SIP Profile again. In the SIP Profile object that appears, either enter a name that identifies this SIP Profile or accept the default name already entered. In this example the SIP Profile was labeled Delayed_Media_En.

• Enable the Outbound Delayed Media by selecting Enabled from drop down menu of the Outbound Delayed Media field. For more information on the SIP Profile (SGP) pane refer to the SIP Profile - SGP topic.

Create an External Network Element

The SIP Channel group that will get created is used to communicate with an external SIP entity. Create an External Network Element and then an external remote gateway that the SIP channel group will transmit messaging to.

• Right click on the Dialogic object and select New External Network Elements. The External Network Elements object is a container object and no configuration is needed in this object. Refer to External Network Elements for more information.

• Right click on External Network Elements object and select New External Gateways. The External Gateways object is also a container object. Under the External Gateways object, multiple individual gateways can be created. Refer to External Gateways topic for more information.

• Right click on External Gateways object and select New External Gateway.

Configure SIP Signaling

The configuration above displays how to configure the SIP Profile and External SIP Gateway so that the Delayed Media feature is configured. The next step is to configure the SIP signaling stack and SIP Channel Groups. Refer to the Configure SIP (Single SIP IP) topic for a procedure on how to configure the SIP functionality.