Call Processing Language (CPL), as described, for example, in J. Lennox and H. Schulzrinne, ???CPL: A Language for User Control of Internet Telephony Services,??? Draft RFC draft-ietf-iptel-cpl-05.txt, November 2001, is a language that is proposed for SIP proxies. [0007] CPL allows users to specify in advance how to select a specific URL given characteristics of a SIP INVITE message (that is used