RFC 2794 (rfc2794) - Page 2 of 9

Mobile IP Network Access Identifier Extension for IPv4

RFC 2794                    Mobile Node NAI                   March 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) [1].  This document
   specifies the Mobile Node NAI extension to the Mobile IP Registration
   Request [7] 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 [8] 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 memo
   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 [3].

2. Mobile Node NAI Extension

   The Mobile Node NAI extension, shown in figure 1, contains the user
   name following the format defined in [1].  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.








Calhoun & Perkins           Standards Track