Criteria for Evaluating Roaming Protocols
RFC 2477

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Network Working Group                                          B. Aboba
Request for Comments: 2477                                      G. Zorn
Category: Informational                           Microsoft Corporation
                                                           January 1999

               Criteria for Evaluating Roaming Protocols

Status of this Memo

   This memo provides information for the Internet community.  It does
   not specify an Internet standard of any kind.  Distribution of this
   memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (1999).  All Rights Reserved.

1.  Abstract

   This document describes requirements for the provisioning of "roaming
   capability" for dialup Internet users.  "Roaming capability" is
   defined as the ability to use multiple Internet service providers
   (ISPs), while maintaining a formal, customer-vendor relationship with
   only one.

2.  Introduction

   Operational roaming services are currently providing worldwide
   roaming capabilities, and these services continue to grow in
   popularity [1].  Interested parties have included:

      Regional Internet Service Providers (ISPs) operating within a
      particular state or province, looking to combine their efforts
      with those of other regional providers to offer services over a
      wider area.

      National ISPs wishing to combine their operations with those of
      one or more ISPs in another nation to provide greater coverage 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 can
      include Internet access as well as secure access to corporate
      intranets via a Virtual Private Network (VPN).

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RFC 2477              Evaluating Roaming Protocols          January 1999

   This document provides an architectural framework for the
   provisioning of roaming capabilities, as well as describing the
   requirements that must be met by elements of the architecture.

2.1.  Requirements language

   In this document, the key words "MAY", "MUST, "MUST NOT", "optional",
   "recommended", "SHOULD", and "SHOULD NOT", are to be interpreted as
   described in [4].

   Please note that the requirements specified in this document are to
   be used in evaluating protocol submissions.  As such, the
   requirements language refers to capabilities of these protocols; the
   protocol documents will specify whether these features are required,
   recommended, or optional for use in roaming.  For example, requiring
   that a protocol support confidentiality is NOT the same thing as
   requiring that all protocol traffic be encrypted.

   A protocol submission is not compliant if it fails to satisfy one or
   more of the must or must not requirements for the capabilities that
   it implements.  A protocol submission that satisfies all the must,
   must not, should and should not requirements for its capabilities is
   said to be "unconditionally compliant"; one that satisfies all the
   must and must not requirements but not all the should or should not
   requirements for its protocols is said to be "conditionally
   compliant."

2.2.  Terminology

   This document frequently uses the following terms:

   phone book
      This is a database or document containing data pertaining to
      dialup access, including phone numbers and any associated
      attributes.

   phone book server
      This is a server that maintains the latest version of the phone
      book.  Clients communicate with phone book servers in order to
      keep their phone books up to date.

   Network Access Server
      The Network Access Server (NAS) is the device that clients dial in
      order to get access to the network.

   Authentication server
      This is a server which provides for authentication/authorization
      within the roaming architecture.

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   Accounting server
      This is a server which provides for accounting within the roaming
      architecture.

   Authentication proxy
      Authentication proxies may be deployed within the roaming
      architecture for several purposes, including authentication
      forwarding, policy implementation, shared secret management, and
      attribute editing.  To the NAS, the authentication proxy appears
      to act as an authentication server; to the authentication server,
      the proxy appears to act as an authentication client.

   Accounting proxy
      Accounting proxies may be deployed within the roaming architecture
      for several purposes, including accounting forwarding, reliability
      improvement, auditing, and "pseudo-transactional" capability.  To
      the NAS, the accounting proxy appears to act as an accounting