Internet - Draft SIP Capabilities

Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet-Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." Abstract This specification defines mechanisms by which a Session Initiation Protocol (SIP) user agent can convey its capabilities and characteristics to other user agents. These capabilities are conveyed as parameters of the Contact header field.