ROAMOPS Working Group Bernard Aboba INTERNET-DRAFT Microsoft Category: Standards Track <draft-ietf-roamops-nai-03.txt> May 22, 1997 The Network Access Identifier 1. Status of this Memo This document is an Internet-Draft. Internet-Drafts are working docu- ments of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute work- ing 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.'' To learn the current status of any Internet-Draft, please check the ``1id-abstracts.txt'' listing contained in the Internet-Drafts Shadow Directories on ds.internic.net (US East Coast), nic.nordu.net (Europe), ftp.isi.edu (US West Coast), or munnari.oz.au (Pacific Rim). The distribution of this memo is unlimited. It is filed as <draft- ietf-roamops-nai-03.txt> and expires January 1, 1998. Please send comments to the authors. 2. Abstract In order to enhance the interoperability of roaming and tunneling ser- vices, it is desirable to have a standardized method for identifying users. This document proposes syntax for the Network Access Identifier (NAI). It is expected that this will be of interest for support of roaming as well as tunneling. "Roaming capability" may be loosely defined as the ability to use any one of multiple Internet service providers (ISPs), while maintaining a formal, customer-vendor rela- tionship with only one. Examples of cases where roaming capability might be required include ISP "confederations" and ISP-provided cor- porate network access support. 3. Introduction Considerable interest has arisen recently in a set of features that fit within the general category of "roaming capability" for dialup Internet users. Interested parties have included: Regional Internet Service Providers (ISPs) operating within a particular state or province, looking to combine their efforts Aboba [Page 1]
INTERNET-DRAFT May 22, 1997 with those of other regional providers to offer dialup service over a wider area. National ISPs wishing to combine their operations with those of one or more ISPs in another nation to offer more comprehensive dialup service in a group of countries or on a continent. Businesses desiring to offer their employees a comprehensive package of dialup services on a global basis. Those services may include Internet access as well as secure access to corporate intranets via a Virtual Private Network (VPN), enabled by tunnel- ing protocols such as PPTP, L2F and L2TP. In order to enhance the interoperability of roaming and tunneling ser- vices, it is desirable to have a standardized method for identifying users. This document proposes syntax for the Network Access Identifier (NAI). Methods for authentication routing or determination of tunnel server endpoints will be addressed in future documents. 3.1. Terminology This document frequently uses the following terms: Network Access Identifier The Network Access Identifier (NAI) is the userID submitted by the client during PPP authentication. In roaming, the purpose of the NAI is to identify the user as well as to assist in the routing of the authentication request. Please note that the NAI may not necessarily be the same as the user's e-mail address or the userID submitted in an applica- tion layer authentication. Network Access Server The Network Access Server (NAS) is the device that clients dial in order to get access to the network. In PPTP termi- nology this is referred to as the PPTP Access Concentrator (PAC), and in L2TP terminology, it is referred to as the L2TP Access Concentrator (LAC). 3.2. Purpose As described in [1], there are now at least five services implementing dialup roaming, and the number of Internet Service Providers involved in roaming consortia is increasing rapidly. In order to be able to offer roaming capability, one of the require- ments is to be able to identify the user's home authentication server. For use in roaming, this function is accomplished via the Network Access Identifier (NAI) submitted by the user to the NAS in the ini- tial PPP authentication. It is also expected that PACs and LACs will use the NAI as part of the process of opening a new tunnel, in order Aboba [Page 2]
INTERNET-DRAFT May 22, 1997 to determine the tunnel endpoint. 4. Formal Definition of the NAI As proposed in this document, the Network Access Identifer is of the form user@domain, where the domain is a fully qualified domain name (FQDN). 4.1. BNF for the NAI The grammar for the NAI is given below, using the augmented BNF nota- tion described in reference [9]. NAI = USERNAME "@" FQDN FQDN = token "." token *[ "." token ] USERNAME = token Examples of valid Network Access Identifiers include: fred@bigco.com nancy@eng.bigco.edu Examples of invalid Network Access Identifiers include: bigco howard.edu fred@bigco.com@smallco.com bigco!fred@smallco.com bigco%fred@smallco.com 5. Acknowledgements Thanks to Glen Zorn of Microsoft for many useful discussions of this problem space. 6. References [1] B. Aboba, J. Lu, J. Alsop, J. Ding, W. Wang. "Review of Roaming Implementations." Work in progress, draft-ietf-roamops-imprev-02.txt, Microsoft, Aimnet, i-Pass Alliance, Asiainfo, Merit, May, 1997. [2] C. Rigney, A. Rubens, W. Simpson, S. Willens. "Remote Authenti- cation Dial In User Service (RADIUS)." RFC 2058, Livingston, Merit, Daydreamer, January, 1997. [3] C. Rigney. "RADIUS Accounting." RFC 2059, Livingston, January, 1997. [4] R. Fielding, et al. "Hypertext Transfer Protocol - HTTP/1.1." draft-ietf-http-v11-spec-07, UC Irvine, August, 1996. Aboba [Page 3]
INTERNET-DRAFT May 22, 1997 7. Authors' Addresses Bernard Aboba Microsoft Corporation One Microsoft Way Redmond, WA 98052 Phone: 206-936-6605 EMail: bernarda@microsoft.com Aboba [Page 4]
