SIP Phone Context Parameter

The Phone-Context parameter is defined in RFC 3966 and is part of the URI scheme tel. The IMG 2020 supports the Phone Context parameter on the outgoing To/From headers in the SIP INVITE message. The Phone Context feature is configured in the SIP Profile object and by default is set to Disabled. See below.

Call Flow

Below is Call Flow Diagram of the Phone Context Parameter being used in a call. Refer to the Call Trace below when viewing the Call Flow diagram.

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Call Trace Example

To view a Call Trace of the above call flow, click Call Trace - SIP Phone Context.

Configuration

The Phone Context parameter is configured through the SIP Profile object. Below are steps to configure the IMG 2020 to output the Phone Context parameter in the SIP INVITE message.

Initial Configuration

The procedure below explains how to configure the SIP Phone Context parameter feature on the IMG 2020. Before configuring, the IMG 2020 must have an initial configuration created on it. Follow the Basic Configurations procedure before proceeding.

Create SIP Profile (SGP)

Create a SIP Profile object. Within the SIP Profile object, the Trusted and SIP Privacy fields can be configured. Once the SIP Profile is configured, it can be linked with entities inside and outside of the trusted domain

• Create a SIP Profile. Right click on the Dialogic object and select New Profiles. The Profiles object is a parent or container object and no configuration is needed here.

• Right click on the 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 Profiles object just created again and select New SIP Profile. Either enter a Name into the name field that identifies this profile or accept the default entry. The name entered in this procedure was SIP_PhoneContext_Profile.

• Right click on the SIP Profile object just created and select New SIP Advanced Settings. To enable the Phone Context Support feature, select from drop down menu where to include the Phone Context parameter. SIP Phone context feature is by default set to disable. Refer to the screen capture below.
  
  

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• Click in the Phone Context String field and enter a Phone Context String. Max number of characters is 64. Below are a few examples:

Create a Remote Gateway

Create an external network element and link the SIP profile created with the remote SIP gateway. Follow procedure below to communicate with a remote gateway.

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

• Right click on External Network Elements and select New External Gateways. The External Gateways object is a parent or container object also and no configuration is needed here. Refer to External Gateways for more information.

• Right click on External Gateways and select New External Gateway. Enter a name that identifies the gateway being configured. In this example the gateway was labeled PhoneContext_GW.

Configure SIP Signaling

The configuration above displays how to configure the SIP Profile and External SIP Gateway so that the SIP Phone Context Parameter functionality 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.

Additional Information

• Phone-context parameter is available for outgoing INVITE requests only.

• If phone-context parameter appears in an incoming SIP message, the SIP stack will ignore it.

• The Phone-Context String field has a maximum length of 64 ASCII characters.