The Session Initiation Protocol (SIP) Refer Method

Status of this Memo This document specifies an Internet standards track protocol for the Internet community, and requests discussion and suggestions for improvements. Please refer to the current edition of the "Internet Official Protocol Standards" (STD 1) for the standardization state and status of this protocol. Distribution of this memo is unlimited. Abstract This document defines the REFER method. This Session Initiation Protocol (SIP) extension requests that the recipient REFER to a resource provided in the request. It provides a mechanism allowing the party sending the REFER to be notified of the outcome of the referenced request. This can be used to enable many applications, including call transfer. In addition to the REFER method, this document defines the the refer event package and the Refer-To request header. 1. Overview This document defines the REFER method. This SIP [1] extension requests that the recipient REFER to a resource provided in the request. This can be used to enable many applications, including Call Transfer. For instance, if Alice is in a call with Bob, and decides Bob needs to talk to Carol, Alice can instruct her SIP user agent (UA) to send a SIP REFER request to Bob's UA providing Carol's SIP Contact information. Assuming Bob has given it permission, Bob's UA will attempt to call Carol using that contact. Bob's UA will then report whether it succeeded in reaching the contact to Alice's UA.