ROAMOPS Working Group Bernard Aboba INTERNET-DRAFT Microsoft Category: Updates RFC 2138 9 March 1998 Support for Mobile IP in Roaming 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 mate- rial 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 , and expires September 1, 1998. Please send comments to the authors. 2. Abstract This document describes how Mobile IP may be supported in roaming, via definition of a RADIUS attribute for Mobile-IP v4 Configuration Option, as described in RFC 2290. 3. Introduction As described in [6], support for Mobile IP is a requirement for a roaming standard. RFC 2290 [8] describes the Mobile-IPv4 Configuration Option for PPP IPCP. This option allows two PPP peers to communicate their support for Mobile IP, as well as for the NAS to pass the home address to the dial-in user. In order to permit Mobile IP configuration in roaming services, this document defines modifications to the RADIUS Framed-IP-Address Attribute, as well as defining a new Mobile-IP-Configuration attribute. Aboba [Page 1] INTERNET-DRAFT 9 March 1998 4. Attribute definitions 4.1. Framed-IP-Address Description This Attribute indicates the address to be configured for the user. It MAY be used in Access-Accept packets. It MAY be used in an Access-Request packet as a hint by the NAS to the server that it would prefer that address, but the server is not required to honor the hint. A summary of the Framed-IP-Address Attribute 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 2 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Length | Address +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Address (cont) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Type 8 for Framed-IP-Address Length 6 Address The Address field is four octets. The value 0xFFFFFFFF indicates that the NAS should allow the user to select an address (e.g. Negotiated). The value 0xFFFFFFFE indicates that the NAS should select an address for the user (e.g. Assigned from a pool of addresses kept by the NAS). The value 0xFFFFFFFD indicates that Mobile IP will be configured for the user, and therefore that the NAS should not select an address for the user, Other valid values indicate that the NAS should use that value as the user's IP address. 4.2. Mobile-IP-Configuration Description This Attribute indicates the Mobile-IP Home Address to be config- ured for the user. It MAY be used in Access-Accept packets. A summary of the Mobile-IP-Configuration Attribute format is shown below. The fields are transmitted from left to right. Aboba [Page 2] INTERNET-DRAFT 9 March 1998 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 2 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Length | Address +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Address (cont) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Type ? for Mobile-IP-Configuration Length 6 Address The Address field is four octets, and encodes the Mobile Node's Home Address. This field MUST NOT be zero. 5. Acknowledgements Thanks to Glen Zorn of Microsoft for useful discussions of this prob- lem space. 6. References [1] B. Aboba, J. Lu, J. Alsop, J. Ding, W. Wang. "Review of Roaming Implementations." RFC 2194, Microsoft, Aimnet, i-Pass Alliance, Asi- ainfo, Merit, September 1997. [2] C. Rigney, A. Rubens, W. Simpson, S. Willens. "Remote Authenti- cation Dial In User Service (RADIUS)." RFC 2138, Livingston, Merit, Daydreamer, April 1997. [3] C. Rigney. "RADIUS Accounting." RFC 2139, Livingston, April 1997. [4] S. Bradner. "Key words for use in RFCs to Indicate Requirement Levels." RFC 2119, Harvard University, March, 1997. [5] C. Rigney, W. Willats. "RADIUS Extensions." Internet draft (work in progress), draft-ietf-radius-ext-01.txt, Livingston, December 1997. [6] B. Aboba, G. Zorn. "Roaming Requirements," Internet draft (work in progress), draft-ietf-roamops-roamreq-07.txt, Microsoft, March 1998. [7] C. Perkins. "IP Mobility Support." RFC 2002, IBM October 1996. [8] J. Solomon, S. Glass, "Mobile-IPv4 Configuration Option for PPP Aboba [Page 3] INTERNET-DRAFT 9 March 1998 IPCP." RFC 2290, Motorola, FTP Software, February 1998. 7. Authors' Addresses Bernard Aboba Microsoft Corporation One Microsoft Way Redmond, WA 98052 Phone: 425-936-6605 EMail: bernarda@microsoft.com Aboba [Page 4]