This document describes a set of extensions to SIP which allow a caller to express preferences about request handling in servers. These preferences include the ability to select which URIs a call gets proxied or redirected to, and to specify certain request handling directives in proxies and redirect servers. It does so by defining three new request headers, Accept-Contact, Reject-Contact and Request-Disposition, which specify the callers preferences. The extension also defines new parameters for the Contact header. These extra parameters are present in the Contact header in REGISTER requests, and are used to associated attributes with particular addresses.
Last updated by Henning Schulzrinne