[Docs] [txt|pdf] [Tracker] [WG] [Email] [Nits] [IPR]

Versions: 00 01 02 03 04 05 06 RFC 2794

Mobile IP Working Group                                   Pat R. Calhoun
INTERNET DRAFT                                    Sun Microsystems, Inc.
25 February 1999                                      Charles E. Perkins
                                                  Sun Microsystems, Inc.

             Mobile IP Network Address Identifier Extension
                   draft-ietf-mobileip-mn-nai-00.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@smallworks.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, such as RADIUS and DIAMETER, are in use within the
   Internet today to provide authentication and authorization services
   for dial-up computers.  We propose that such services are equally
   valuable for mobile nodes using Mobile IP when the nodes are
   attempting to connect to foreign domains with AAA servers.  Such
   AAA servers typically identify clients by using the Network Access
   Identifier (NAI). We propose that the NAI be allowed for use with
   Mobile IP when the mobile node issues a Registration Request.








Calhoun, Perkins             Expires 25 August 1999             [Page i]


Internet Draft             Mobile Node NAI              25 February 1999


1. Introduction

   AAA servers, such as RADIUS and DIAMETER, are in use within the
   Internet today to provide authentication and authorization services
   for dial-up computers.  We propose that such services are equally
   valuable for mobile nodes using Mobile IP when the nodes are
   attempting to connect to foreign domains with AAA servers.  Such
   AAA servers typically identify clients by using the Network Access
   Identifier (NAI). We propose that the NAI be allowed for use with
   Mobile IP when the mobile node issues a Registration Request.  This
   draft specifies the Mobile-Node-NAI Extension to the Mobile IP
   Registration Request message from the Mobile Node.

   Since the NAI is typically used to 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.  This draft introduces new entity
   named the Home Domain Allocation Agency (HDAA) that can dynamically
   assign a Home Address to the Mobile Node.  A message containing the
   Mobile-Node-NAI extension MAY have the Home Address field in the
   Registration Request set to zero (0) to request that one be assigned.

   In the figure 1, we introduce the Home Domain Allocator Agency
   (HDAA), which receives messages from Foreign Agents and assigns a
   Home Address, and possibly a Home Agent, within the Home Domain.  The
   HDAA does not perform any Mobile IP processing on the Registration
   Request, but simply forwards the request to a Home Agent within the
   network that is able to handle the request.

   Mobile IP [6] defines a method for a Mobile Node to be assigned
   a Home Agent dynamically through the use of a limited broadcast
   message.  However, most corporate networks do not allow such packets
   to traverse their firewall.  The use of the limited broadcast ensured
   that the Home Agent assigned to the Mobile Node resided on a specific
   subnet, therefore it was not necessary to assign a dynamic IP
   Address to the Mobile Node.  With the Mobile-Node-NAI extension, we
   propose that the the HDAA may also assign a dynamic Home Agent to the
   Mobile Node.  This alternative mechanism avoids the use of limited
   broadcast.

   A Registration Request with the Mobile-Node-NAI extension MAY have
   the Home Agent field set to zero (0) to request that a home agent
   be dynamically assigned.  Such a registration MUST be forwarded
   to an HDAA, which is able to assign the Home Address.  The domain
   portion of the NAI [1] is used to identify the Mobile Node's Home
   Domain, and thus to identify the HDAA which is the destination of the
   Registration Request.  The DIAMETER Mobile IP extension [3] defines a




Calhoun, Perkins             Expires 25 August 1999             [Page 1]


Internet Draft             Mobile Node NAI              25 February 1999


   method of resolving the Home Agent allocator, but this document will
   refer to a generic method for full generality.


                                                     +------+
                                                     |      |
                                                 +---+ HA-1 |
        +------+       +------+       +------+   |   |      |
        |      |       |      |       |      |   |   +------+
        |  MN  |-------|  FA  |-------| HDAA +---+     ...
        |      |       |      |       |      |   |   +------+
        +------+       +------+       +------+   |   |      |
                                                 +---+ HA-n |
                                                     |      |
                                                     +------+


             Figure 1: Home Domain Allocator Agency (HDAA)


   Upon receipt of the Registration Request, the Foreign Agent extracts
   the Mobile Node's NAI and finds the domain name associated with it.
   The Foreign Agent then finds the HDAA that handles requests for the
   Mobile Node's domain.  The discovery protocol is outside of the
   scope of this specification.  As an example, however, the FA might
   typically delegate the duty of finding a HDAA to a local AAA server.

   The Registration Reply from the Home Agent MUST include the Mobile-
   Node-NAI extension.  The Registration Reply MUST include a nonzero
   Home Agent address and Mobile Node's Home Address.


2. Mobile-Node-NAI Extension

   The Mobile-Node-NAI Extension contains the user and/or host name
   following the format defined in [1].  The NAI is used to identify a
   user or host and can be used to find a HDAA within the requestor's
   home domain.

   When present in the Registration Request, the Home Agent and Home
   Address fields MAY be set to zero (0).  Since the foreign agent
   cannot use the Home Address in the reply to identify the Mobile Node,
   it MUST use the NAI instead in its pending registration request
   records.  If the foreign agent cannot manage pending registration
   request records in this way, it MUST return a Registration Reply with
   status 77 (unexpected extension).

   The Mobile-Node-NAI Extension, shown in figure 2, MUST appear before
   the Foreign-Home Authentication Extension.



Calhoun, Perkins             Expires 25 August 1999             [Page 2]


Internet Draft             Mobile Node NAI              25 February 1999


       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 2: The Mobile-Node-NAI Extension



      Type       TDB

      Length

      Mobile-Node-NAI Contains the username or host name in the format
                 defined in [1].


3. Security Considerations

   This document assumes that the Mobile IP messages are authenticated
   using a method defined by the Mobile IP protocol.  This proposal does
   require that the Mobile Node's NAI be sent in the clear over the
   network, but that is not expected to be a security issue.


4. IPv6 considerations

   For mobile nodes using IPv6, there are no commonly deployed
   mechanisms by which a mobile node may verify credentials, such
   as there are with IPv4.  Nevertheless, it may be the case that
   mobile nodes using IPv6 mobility would like 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 forward the mobile
   node's binding update, and thus to manage the verification of the
   credentials offered by the mobile node.  In order for the NAI to
   serve the purpose of identifying the home AAA 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 local agent can be identified as either the router sending out
   Router Advertisements [5] for use by the mobile node with stateless
   address autoconfiguration, or as an appropriate DHCPv6 [2] server.
   In the former case, the ability to handle the NAI would be signaled
   by the router in question by attaching a new extension to the Router
   Advertisement.  In the latter case, for managed links, the mobile



Calhoun, Perkins             Expires 25 August 1999             [Page 3]


Internet Draft             Mobile Node NAI              25 February 1999


   node would include an NAI extension to the DHCP Solicitation for use
   by the DHCP server.  The NAI extension would also be required on the
   subsequent DHCP Request unicast by the mobile node to the DHCP Server
   selected on the basis of received DHCP Advertisements.


5. Acknowledgements

   The authors would like to thank Gabriel Montenegro and Vipul Gupta
   for their useful discussions.


References

   [1] B. Aboba and M. A. Beadles.  The network access identifier.
       draft-ietf-roamops-nai-12.txt, November 1998.  (work in
       progress).

   [2] J. Bound and C. Perkins.  Dynamic Host Configuration Protocol
       for IPv6.  draft-ietf-dhc-dhcpv6-14.txt, June 1998.  (work in
       progress).

   [3] P. Calhoun and C. E. Perkins.  DIAMETER Mobile IP Extensions.
       draft-calhoun-diameter-mobileip-01.txt, November 1998.  (work in
       progress).

   [4] T. Narten, E. Nordmark, and W. Simpson.  Neighbor Discovery for
       IP version 6 (IPv6).  RFC 1970, August 1996.

   [5] T. Narten, E. Nordmark, and W. Simpson.  RFC 2461:  Neighbor
       discovery for IP Version 6 (IPv6), December 1998.  Obsoletes
       RFC1970 [4]. Status:  DRAFT STANDARD.

   [6] C. Perkins, Editor.  IP Mobility Support.  RFC 2002, October
       1996.


Chairs' Addresses

   The working group can be contacted via the current chairs:

      Jim Solomon                             Erik Nordmark
      Redback Networks, Inc.                  Sun Microsystems, Inc.
      1301 E. Algonquin Road                  17 Network Circle
      Schaumburg, IL 60196                    Menlo Park, California 94025
      USA                                     USA

      Phone:  +1-847-576-2753                 Phone:  +1 650 786-5166
      Fax:                                    Fax:  +1 650 786-5896



Calhoun, Perkins             Expires 25 August 1999             [Page 4]


Internet Draft             Mobile Node NAI              25 February 1999


      E-mail:  solomon@redbacknetworks.com    E-mail:  nordmark@sun.com



Author's Addresses

   Questions about this memo can be directed to:

      Pat R. Calhoun                    Charles E. Perkins
      Sun Microsystems Laboratories     Sun Microsystems Laboratories
      15 Network Circle                 15 Network Circle
      Menlo Park, CA 94025              Menlo Park, CA 94025
      USA                               USA

      Phone:  +1-650-786-7733           Phone:  +1 650 786-6464
      EMail:  pat.calhoun@sun.com       EMail:  cperkins@eng.sun.com
                                        Fax:  +1 650 786-6445



































Calhoun, Perkins             Expires 25 August 1999             [Page 5]


Html markup produced by rfcmarkup 1.129b, available from https://tools.ietf.org/tools/rfcmarkup/