INTERNET DRAFT JUNHYUK SONG March 2002 SAMSUNG ELECTRONICS DONGKIE LEE SK TELECOM DNS RR type for NAI draft-song-dnsext-nai-support-01.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 This document proposes the use of the new DNS RR type "NAI" (Network Access Identifier) [RFC2486] to specify dynamically assigned IP address. Song Expires September 2002 [Page 1] Internet Draft March 2002 1. Introduction The use of the wireless mobile networking has been dramatically increased thanks to rapid development of wireless technology and commercial deployment of Mobile IP technology [RFC3220]. The most recent release of Mobile IPv4 supports the dynamic Home Address assignment mechanism that allow MN (Mobile Node) being identified by NAI (Network Access Identifier) [RFC2486] rather than static Home IP address. NAI has a prominent role on the mobile network environment. This is not only because NAI significantly reduces the IPv4 address shortage problem and but also it provides the standardized method for identifying users in order to accomplish the interoperability for roaming over multiple ISPs (Internet Service Providers). The most of the Mobile IPv4 deployment including 3GPP2 CDMA2000 wireless packet data system architecture [P.S0001-B] identify the Mobile Node by NAI. Therefore the need for standardized method of binding the ever changing home address of the MN over various ISPs to NAI is necessary. The DNS basically provides a mechanism to map between hostnames and IP address with support of many other RRs thorough hierarchically built domain names. The NAI is of the form user@realm [RFC2486]. Adding NAI as a DNS RR shall enable tracking of the dynamically changed home IP address. This document specifies a new RR type for NAI, mapping host IP address and user identifier (NAI) [RFC2486]. 2. Applicability Statement Mobile IPv4 is designed to provide the IP mobility that provides reasonably seamless IP connectivity. Since the MN (Mobile Node) is no longer necessarily identified by the unique home IP address, the mechanism for the locating and updating newly assigned home IP address is required [UM]. The NAI RR defines user identifier, NAI widely used for PPP dialup connection and Mobile IPv4. The basic idea is to let mobile Internet user to constantly update its IP address, while moving around multiple access provider network. It can enables correspondent user to always reach the specific user by querying NAI to name server, regardless of the connecting location. It is expected that NAI RR will be used in IRS(Internet Reachability Service) of 3GPP2 wireless IP network standard [P.S0001-B] (see Appendix A). Song Expires September 2002 [Page 2] Internet Draft March 2002 The applications that running on the Dynamic Home Address Allocation enabled Mobile IPv4 MN (Mobile node) depends on the one to one mapping of NAI and newly assigned mobile host IP address in DNS name server for the connectivity with Correspondent nodes. Because it will be the only way the CN (Correspondent Node) can find the Mobile Node's newly assigned IP address. An example of application is including WWW server, IP push service, Instant Messaging, Multi-user Network games, Multi-chat, etc. 3. NAI RR Type NAI name space is resemble to Domain Name Space, except that it is a sequence of one or more labels, made of the user identifier and domain name. The "@" sign before realm, shall be treated as a delimiter to flag user ID part. Every user Identifier shall end with "@" sign and placed before domain name. NAI records cause no additional section processing The NAI record has the DNS RR type of "?", hence has the same QTYPE number of "?". Note NAI RR requires IANA number assignment. The class of NAI RR is defined in the IN class only. TTL should be configured to minimize the time of the RR being cached The RDATA of NAI is same as A RDATA format, 32 bit Internet Address 4. Examples Resource Record for NAI(junhyuk@xbs.samsung.co.kr) is like below: junhyuk@.xbs.samsung.co.kr. 1440 IN NAI 165.213.221.4 5. IANA Considerations It requires new RR type number from IANA. 6. Acknowledgements Special thanks to Professor Murali Venkatesh of Syracuse University Song Expires September 2002 [Page 3] Internet Draft March 2002 Appendix A. IRS of 3GPP2 wireless IP Network standard In this example, I've omitted the detail operation of deleting DNS record in case of user disconnect. In IRS, it is assumed that MS desires to be reached by a fixed identifier such as an NAI-like hostname 1. Simple IP operation Upon connecting to new access network MS(Mobile Station) shall generate CHAP authentication with NAI for user authentication. After successfully authenticate the user authentication request, AAAH shall send DNS A record update message to name server. (See figure 1) +--------------+ PPP CHAP (3) +--------------+ | | Auth Req | AAAH | | AAAF |-------------->| | | |<--------------| | +--------------+ PPP CHAP(5) +--------------+ ^ | Auth Ack | PPP CHAP | | User | Auth Req | | PPP CHAP Location | (2) | | Auth Ack Update(4)| | | (6) v | v +---------------+ +------+ PPP CHAP +-----------+ | Name Server | | | Auth Req (1) | | +---------------+ | |---------------------->| PDSN | ^ | |<----------------------| | User | | MS | PPP CHAP | | Location | | | Auth Ack (7) | | Query | | |<--------------------->| | | | | IP data (8) | | +-------+ +------+ | | <-----------| CH | +-----------+ IP data +-------+ Figure 1: Simple IPv4 operation Song Expires September 2002 [Page 4] Internet Draft March 2002 2. Mobile IP operation When the HA receives and successfully replies to an initial Mobile IP Registration Request, it performs the DNS update for the MS if it has previously received an indication from the home RADIUS server to do so, or has otherwise been provisioned to do so. The HA shall send a DNS Update message [RFC 2136] to the DNS server to add a Resource Record for the MS, if so required by the home RADIUS server [4]. (See figure 2) +--------------+ +--------------+ | |---------------->| | | AAAF | | AAAH | | |<----------------| | +--------------+ +--------------+ ^ | ^ Access | | Access | Request | v Accept v +------+ Agent +--------------+ +--------------+ | |Advertisement | | | | | | with FAC | PDSN/FA | | Mobile IPv4 | | MS |<------------ | | | Home Agent | | |------------> | |---------------->| | | |Mobile IP RRQ | |Mobile IP RRQ | | | |with MN-AAA | | | | | |<-------------| |<----------------| | +------+Mobile IP RRP +--------------+Mobile IP RRP +--------------+ | User | Location | Update | v +--------------+ | Name Server | +--------------+ Figure 2: Mobile IPv4 operation Song Expires September 2002 [Page 5] Internet Draft March 2002 References [RFC3220] C. Perkins, Editor. "IP Mobility Support". RFC 3320. January 2002. [UM] J.H Song, DK Lee "draft-song-network-user-mobility-00.txt" Work in Progress [RFC2486] Bernard Aboba and Mark A. Beadles "The Network Access Identifier". RFC 2486. January 1999. [P.S0001-B] 3GPP2 P.S0001-B work in progress. ftp://ftp.3gpp2.org/TSGP/Standard/ 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 DONGKIE LEE SK TELECOM Core Network Development Team Network R&D Center Phone +82-2-829-4640 Email: galahad@netsgo.com FAX:+82-2-829-4612 Song Expires September 2002 [Page 6] Internet Draft March 2002 Full Copyright Statement Copyright (C) The Internet Society (2002). All Rights Reserved. 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