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Refer to Phone Number

Overview

This feature allows the CSP to support a telephone number in an outbound REFER method.

Pertinent Specification

RFC 3515

Description

REFER is a SIP method as defined by RFC 3261 that indicates that the recipient (identified by the Request-URI) should contact a third party using the contact information provided in the request. Refer-To is a request header field with in the REFER method as defined by RFC 3515.

Prior to this feature, the CSP supports only the SIP URL in the Refer-To header. The host had to provide the username and host name in the PPL Event Request method to generate the REFER. By default CSP fills in the port number, in case the host has not supplied it. There was no provision for the host to use a telephone number in Refer-To header.

With this feature, the CSP supports telephone number in an outbound REFER method.

Important! The telephone number supplied by the host is not validated by CSP.

How Supplied

The CSP SIP Stack allows the host to supply the telephone number in an outbound REFER method. The username TLV (0x291E) is optional in the PPL Event Request to generate REFER method.

Only host name TLV (0x2920) will be mandatory. The CSP will not fill the port number by default. To refer to a telephone number the host supplies only the host name TLV containing the telephone number. To refer to a SIP URL the host has to provide the host name TLV and username TLV.

Example:

The host name TLV supplied by the user for an outbound refer to a telephone number.

Hostname (0x2920): 080-23310818

(in the form of null terminated ASCII string)

The final Header will look as follows:

Refer-To: <sip:080-23310818>

Session-Initiation Protocol. A signaling protocol used for establishing sessions in an IP network. A session could be a simple, two-way telephone call, or it could be a collaborative multi-media conference session.
See Programmable Protocol Language.
Tag-Length-Value block. A standardized block that allows data to inserted in a standard way into API messages.
A condition that, when met, drives a state machine from one state to another. A condition that drives a Component out of its current state by invoking an associated primitive.
American Standard Code for Information Interchange