JUNHYUK SONG INTERNET DRAFT DAEJOONG KIM June 2002 SAMSUNG ELECTRONICS SIP server IPCP configuration option for PPP draft-song-pppext-sip-support-00.txt Status of This Memo Distribution of this memo is unlimited. This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC2026. 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." The list of current Internet-Drafts can be accessed at: http://www.ietf.org/ietf/1id-abstracts.txt The list of Internet-Draft Shadow Directories can be accessed at: http://www.ietf.org/shadow.html. Abstract The Point-to-Point Protocol (PPP) [1] provides a standard method for transporting multi-protocol datagrams over point-to-point links. PPP defines an extensible Link Control Protocol (LCP) for establishing, configuring, and testing the data-link connection; and a family of Network Control Protocols (NCPs) for establishing and configuring different network-layer protocols. This document defines the PPP IPCP configuration option that contains a list of IPv4 addresses of SIP proxy servers. It is just one of the many possible mechanism to locate the SIP proxy server, such as DHCP option [6] and manual configuration. This approach is applicable to the system using PPP for the link layer protocol and IP address allocation (ex. 3GPP2 Packet Data network) Song and Kim Expires December 2002 [Page 1] Internet Draft June 2002 1. Introduction The SIP (Session Initiation Protocol)[3] is a signaling protocol used for the session invitation, modification and termination. The UAC(User Agent Client) sends a request to the UAS(User Agent Server). However, the request message (INVITE) is not directly sent to the callee UAS, it rather go through proxy servers, and possibly redirect servers. This draft is specifying one of the many possible mechanism to locate the SIP proxy server, such as DHCP option[6] and manual configuration. This draft extends the NCP for establishing and configuring the Internet Protocol over PPP [4], by specifying a IPCP option that allows SIP clients to locate a list of SIP proxy servers that is to be used for all SIP requests. This approach is applicable to the system utilizing PPP for the link layer protocol and IP address allocation (ex. 3GPP2 Packet Data network) Note : the format and behavior of these options are quoted from RFC1877 [2] for the sake of consistent implementation of PPP. 2. Configuration Options The Configuration Option format and basic options are defined by IPCP configuration option [4]. The most updated value of the IPCP Option Type field are specified in the IANA web site [IANA-ALLOCATION]. This document concerns the following values: [?] Primary SIP Server Address [?+1] Secondary SIP Server Address 2.1. Primary SIP server Address Option Description This Configuration Option defines a method for negotiating with the remote peer the address of the primary SIP server Address to be used on the local end of the link. By default, no primary SIP server address is provided. A summary of the Primary SIP Address Configuration Option format is shown below. The fields are transmitted from left to right. Song and Kim Expires December 2002 [Page 2] Internet Draft June 2002 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Length | Primary-SIP-Server Address +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Primary-SIP-Server Address(cont)| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Type ? (Primary SIP Proxy server) Length 6 Primary-SIP-Address The four octet Primary-SIP-Server Address is the address of the primary proxy SIP server to be used by the local peer. If all four octets are set to zero, it indicates an explicit request that the peer provide the address information in a Config-Nak packet. Default No address is provided. 1.3. Secondary SIP Server Address Description This Configuration Option defines a method for negotiating with the remote peer the address of the secondary SIP server Address to be used on the local end of the link. By default, no secondary SIP address is provided. Song and Kim Expires December 2002 [Page 3] Internet Draft June 2002 A summary of the Secondary SIP Address Configuration Option format is shown below. The fields are transmitted from left to right. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Length |Secondary-SIP-Server Address +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Secondary-SIP-Server Addr (cont)| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Type ?+1 (Secondary SIP Proxy server) Length 6 Secondary-SIP-Address The four octet Secondary-SIP-Server Address is the address of the secondary SIP server to be used by the local peer. If all four octets are set to zero, it indicates an explicit request that the peer provide the address information in a Config-Nak packet. Default No address is provided. 3. IANA Considerations Requires IPCP option number assignment 4. Acknowledgements A major portion of the text in this memo was quoted from RFC 1877. Song and Kim Expires December 2002 [Page 4] Internet Draft June 2002 References [1] Simpson, W., Editor, "The Point-to-Point Protocol (PPP)", STD 51, RFC 1661, Daydreamer, July 1994. [2] Steve Cobb, "PPP Internet Protocol Control Protocol Extensions for Name Server Addresses" RFC 1877, Microsoft, [3] M. Handley, H. Schulzrinne, E. Schooler, and J. Rosenberg, "SIP: session initiation protocol," Request for Comments 2543, Internet Engineering Task Force, Mar. 1999. [4] McGregor, G., "PPP Internet Control Protocol", RFC 1332, Merit, May 1992. [5] H. Schulzrinne and J. Rosenberg, "SIP: Session initiation protocol -- locating SIP servers," Internet Draft, Internet Engineering Task Force, Mar. 2001. Work in progress. [6] H. Schulzrinne "DHCPv4 Option for SIP Servers" Internet Draft, Internet Engineering Task Force, Mar. 2001. Work in progress. [IANA-ALLOCATION] Internet Assigned Numbers Authority, http://www.isi.edu/in-notes/iana/assignments/multicast-addresses. Addresses Questions about this memo can be directed to the authors: JUNHYUK SONG SAMSUNG ELECTRONICS. Packet Technology System Lab. Mobile Development Team Phone: +82-31-279-3639 Email: junhyuk@telecom.samsung.co.kr santajunman@yahoo.com DAEJOONG KIM SAMSUNG ELECTRONICS. Packet Technology System Lab. Mobile Development Team Phone: 82-31-279-3625 EMail: daejoong@samsung.com Song and Kim Expires December 2002 [Page 5] Internet Draft June 2002 Full Copyright Statement Copyright (C) The Internet Society (2002). All Rights Reserved. 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