Mobile IP Network Access Identifier Extension for IPv4
The information below is for an old version of the document that is already published as an RFC.
This is an older version of an Internet-Draft that was ultimately published as RFC 2794.
|Author||Charles E. Perkins|
|Last updated||2013-03-02 (Latest revision 2000-01-05)|
|RFC stream||Internet Engineering Task Force (IETF)|
|Additional resources||Mailing list discussion|
|IESG||IESG state||RFC 2794 (Proposed Standard)|
|Send notices to||(None)|
Mobile IP Working Group Pat R. Calhoun INTERNET DRAFT Sun Microsystems Laboratories 5 January 2000 Charles E. Perkins Nokia Research Center Mobile IP Network Access Identifier Extension for IPv4 draft-ietf-mobileip-mn-nai-06.txt Status of This Memo This document is a submission by the mobile-ip Working Group of the Internet Engineering Task Force (IETF). Comments should be submitted to the MOBILE-IP@STANDARDS.NORTELNETWORKS.COM mailing list. 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 AAA servers are in use within the Internet today to provide authentication and authorization services for dial-up computers. Such services are likely to be equally valuable for mobile nodes using Mobile IP when the nodes are attempting to connect to foreign domains with AAA servers. AAA servers today identify clients by using the Network Access Identifier (NAI). Our proposal defines a way for the mobile node to identify itself, by including the NAI along with the Mobile IP Registration Request. This draft also updates RFC2290 which specifies the Mobile-IPv4 Configuration option for IPCP, by allowing the Mobile Node's Home Address field of this option to be zero. Calhoun, Perkins Expires 5 July 2000 [Page i] Internet Draft Mobile Node NAI 5 January 2000 1. Introduction AAA servers are in use within the Internet today to provide authentication and authorization services for dial-up computers. Such services are likely to be equally valuable for mobile nodes using Mobile IP when the nodes are attempting to connect to foreign domains with AAA servers. AAA servers today identify clients by using the Network Access Identifier (NAI) . This document specifies the Mobile Node NAI extension to the Mobile IP Registration Request  message from the mobile node. Since the NAI is typically used to uniquely identify the mobile node, the mobile node's home address is not always necessary to provide that function. Thus, it is possible for a mobile node to authenticate itself, and be authorized for connection to the foreign domain, without even having a home address. A message containing the Mobile Node NAI extension MAY set the Home Address field to zero (0) in the Registration Request, to request that a home address be assigned. The "Mobile-IPv4 Configuration" option to IPCP has been specified in RFC 2290  for proper interaction between a mobile node and a peer, through which the mobile node connects to the network using PPP. According to that specification the Mobile Node's Home Address field of the option MUST not be zero. However, in the context of this draft which allows a mobile node to be identified by its NAI and to obtain an address after the PPP phase of connection establishment, the Home Address field is allowed to be zero while maintaining all other aspects of RFC 2290. Interpretation of various scenarios from RFC 2290 is given in section 4. The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in . Calhoun, Perkins Expires 5 July 2000 [Page 1] Internet Draft Mobile Node NAI 5 January 2000 2. Mobile Node NAI Extension The Mobile Node NAI extension, shown in figure 1, contains the user and/or host name following the format defined in . When it is present in the Registration Request, the Home Address field MAY be set to zero (0). The Mobile Node NAI extension MUST appear in the Registration Request before both the Mobile-Home Authentication extension and Mobile-Foreign Authentication extension, if present. 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 | MN-NAI ... +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 1: The Mobile Node NAI Extension Type 131 (skippable)  Length The length in bytes of the MN-NAI field MN-NAI A string in the NAI format defined in . 3. Foreign Agent Considerations If Home Address is zero in the Registration Request, the foreign agent MUST use the NAI instead in its pending registration request records, along with the Identification field as usual. If the foreign agent cannot manage pending registration request records in this way, it MUST return a Registration Reply with Code indicating NONZERO_HOMEADDR_REQD (see section 5). If the mobile node includes the Mobile Node NAI extension in its Registration Request, then the Registration Reply from the home agent MUST include the Mobile Node NAI extension. If not, the foreign agent SHOULD send the Registration Reply to the mobile node, changing the Code to the value MISSING_NAI (see section 5). The Registration Reply MUST include a nonzero Home Agent address and mobile node's Home Address. If not, the foreign agent SHOULD send the Registration Reply to the mobile node, changing the Code to the value MISSING_HOME_AGENT or MISSING_HOMEADDR, respectively (see section 5). Calhoun, Perkins Expires 5 July 2000 [Page 2] Internet Draft Mobile Node NAI 5 January 2000 4. Interactions with Mobile-IPv4 Configuration Option to IPCP In the Mobile-IPv4 Configuration Option to IPCP , the Mobile Node's Home Address field may be zero. In this section, we specify the action to be taken in that case, when the mobile node is using the Mobile Node NAI extension in the Mobile IP Registration Request. Whether or not the IP Address Configuration Option contains a nonzero IP address, the mobile node will subsequently attempt to obtain a home address from the Mobile IP Registration Reply. If the IP Address Configuration Option to IPCP has IP address equal to zero, the PPP peer is expected to allocate and assign a co-located care-of address to the Mobile Node. If, on the other hand, the IP Address Configuration Option to IPCP has a nonzero IP address, the PPP peer is expected to assign that address to the Mobile Node as its co-located care-of address. 5. Error Values Each entry in the following table contains the name and value for the Code  to be returned in a Registration Reply, and the section in which the error Code is first mentioned in this specification. Error Name Value Section of Document ---------------------- ----- ------------------- NONZERO_HOMEADDR_REQD 96 3 MISSING_NAI 97 3 MISSING_HOME_AGENT 98 3 MISSING_HOMEADDR 99 3 6. IANA Considerations The number for the Mobile Node NAI extension is taken from the numbering space defined for Mobile IP registration extensions defined in RFC 2002  as extended in RFC 2356 . The numbering for the extension also SHOULD NOT conflict with values specified in the Internet Draft for Route Optimization . The Code values specified for errors, listed in section 5, MUST NOT conflict with any other code values listed in RFC 2002, RFC 2344 , or RFC 2356 . They are to be taken from the space of error values conventionally associated with rejection by the foreign agent (i.e., 64-127). Calhoun, Perkins Expires 5 July 2000 [Page 3] Internet Draft Mobile Node NAI 5 January 2000 7. Security Considerations Mobile IP registration messages are authenticated, and the authentication verified by the recipient. This proposal does not prohibit the mobile node from sending its NAI in the clear over the network, but that is not expected to be a security issue. 8. IPv6 Considerations Supporting NAI-based registrations for Mobile IPv6  is outside the scope of this document. This section contains some ideas how Stateless Address Autoconfiguration  and DHCPv6  might be extended to support NAI-based Mobile IPv6 registrations. For mobile nodes using IPv6, there are no commonly deployed mechanisms by which a mobile node may present its credentials, such as exist today with IPv4. Nevertheless, a mobile node using IPv6 mobility may wish to specify the domain in which their credentials may be checked, by using a NAI just as this specification proposes for IPv4. In the case of IPv6, however, there is no foreign agent in place to manage the connectivity of the mobile node, and thus to manage the verification of the credentials offered by the mobile node. To identify the HDAF (see appendix A) that has the expected relationship with the mobile node, the NAI would have to be forwarded to a local AAA by the local agent involved with configuring the care-of address of the mobile node. This agent can either be a router sending out Router Advertisements , or a DHCPv6 server. In the former case, the router could signal its ability to handle the NAI by attaching some yet to be defined option to the Router Advertisement. In the latter case, for managed links, the mobile node could include a yet to be defined NAI extension in its DHCP Solicitation message. Such an NAI extension and appropriate authentication would also be required on the subsequent DHCP Request sent by the mobile node to the DHCP Server selected on the basis of received DHCP Advertisements. Once a care-of address on the foreign network has been obtained, the mobile node can use regular MIPv6 . 9. Acknowledgements The authors would like to thank Gabriel Montenegro and Vipul Gupta for their useful discussions. Thanks to Basaravaj Patil and Pete McCann for text describing actions to be taken when the home address is zero but the mobile node wishes to use the Mobile-IPv4 Configuration Option to IPCP defined in RFC 2290. Calhoun, Perkins Expires 5 July 2000 [Page 4] Internet Draft Mobile Node NAI 5 January 2000 References  B. Aboba and M. Beadles. The Network Access Identifier. Request for Comments (Proposed Standard) 2486, Internet Engineering Task Force, January 1999.  J. Bound and C. Perkins. Dynamic Host Configuration Protocol for IPv6 (DHCPv6). Internet Draft, Internet Engineering Task Force. draft-ietf-dhc-dhcpv6-14.txt, February 1999. Work in progress.  S. Bradner. Key words for use in RFCs to Indicate Requirement Levels. Request for Comments (Best Current Practice) 2119, Internet Engineering Task Force, March 1997.  D. Johnson and C. Perkins. Mobility Support in IPv6. draft-ietf-mobileip-ipv6-08.txt, June 1999. (work in progress).  G. Montenegro. Reverse Tunneling for Mobile IP. Request for Comments (Proposed Standard) 2344, Internet Engineering Task Force, May 1998.  G. Montenegro and V. Gupta. Sun's SKIP Firewall Traversal for Mobile IP. Request for Comments (Informational) 2356, Internet Engineering Task Force, June 1998.  C. Perkins. IP Mobility Support. Request for Comments (Proposed Standard) 2002, Internet Engineering Task Force, October 1996.  C. Perkins and D. Johnson. Route Optimization in Mobile IP. Internet Draft, Internet Engineering Task Force. draft-ietf-mobileip-optim-08.txt, February 1999. Work in progress.  J. Solomon and S. Glass. Mobile-IPv4 Configuration Option for PPP IPCP. Request for Comments (Proposed Standard) 2290, Internet Engineering Task Force, February 1998.  S. Thomson and T. Narten. IPv6 Stateless Address Autoconfiguration. Request for Comments (Draft Standard) 2462, Internet Engineering Task Force, December 1998. Calhoun, Perkins Expires 5 July 2000 [Page 5] Internet Draft Mobile Node NAI 5 January 2000 A. Home Domain Allocation Function (HDAF) This appendix introduces a new function named the Home Domain Allocation Function (HDAF) that can dynamically assign a Home Address to the mobile node. Figure 2 illustrates the Home HDAF, which receives messages from foreign agents (e.g., FA) and assigns a Home Address within the Home Domain. The HDAF does not perform any Mobile IP processing on the Registration Request, but simply forwards the request to a Home Agent (HA) within the network that is able to handle the request. +------+ | | +---+ HA-1 | +------+ +------+ +------+ | | | | | | | | | | +------+ | MN |-------| FA |-------| HDAF +---+ ... | | | | | | | +------+ +------+ +------+ +------+ | | | +---+ HA-n | | | +------+ Figure 2: Home Domain Allocator Function (HDAF) Upon receipt of the Registration Request from the mobile node (MN), FA extracts the NAI and finds the domain name associated with it. FA then finds the HDAF that handles requests for the mobile node's domain. The discovery protocol is outside of the scope of this specification. As an example, however, FA might delegate the duty of finding a HDAF to a local AAA server. The local AAA server may also assist FA in the process of verifying the credentials of the mobile node, using protocols not specified in this document. Calhoun, Perkins Expires 5 July 2000 [Page 6] Internet Draft Mobile Node NAI 5 January 2000 Addresses The working group can be contacted via the current chairs: Basavaraj Patil Phil Roberts Nortel Networks Inc. Motorola 2201 Lakeside Blvd. 1501 West Shure Drive Richardson, TX. 75082-4399 Arlington Heights, IL 60004 USA USA Phone: +1 972-684-1489 Phone: +1 847-632-3148 EMail: firstname.lastname@example.org EMail: QA3445@email.mot.com Questions about this memo can be directed to: Charles E. Perkins Pat R. Calhoun Nokia Research Center Sun Microsystems Laboratories 313 Fairchild Drive 15 Network Circle Mountain View, California 94043 Menlo Park, California 94025 USA USA Phone: +1-650 625-2986 Phone: +1 650-786-7733 EMail: email@example.com EMail: firstname.lastname@example.org Fax: +1 650 625-2502 Fax: +1 650-786-6445 Calhoun, Perkins Expires 5 July 2000 [Page 7]