rfc2194.txt

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Network Working Group                                         B. Aboba
Request for Comments: 2194                                   Microsoft
Category: Informational                                          J. Lu
                                                        AimQuest Corp.
                                                              J. Alsop
                                                       i-Pass Alliance
                                                               J. Ding
                                                              Asiainfo
                                                               W. Wang
                                                   Merit Network, Inc.
                                                        September 1997


                   Review of Roaming Implementations

1.  Status of this Memo

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

2.  Abstract

   This document reviews the design and functionality of existing
   roaming implementations.  "Roaming capability" may be loosely defined
   as the ability to use any one of multiple Internet service providers
   (ISPs), while maintaining a formal, customer-vendor relationship with
   only one.  Examples of cases where roaming capability might be
   required include ISP "confederations" and ISP-provided corporate
   network access support.

3.  Introduction

   Considerable interest has arisen recently in a set of features that
   fit within the general category of "roaming capability" for Internet
   users.  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 service over a
      wider area.

      National ISPs wishing to combine their operations with those of
      one or more ISPs in another nation to offer more comprehensive
      service in a group of countries or on a continent.

      Businesses desiring to offer their employees a comprehensive
      package of access services on a global basis.  Those services may



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      include Internet access as well as secure access to corporate
      intranets via a Virtual Private Network (VPN), enabled by
      tunneling protocols such as PPTP, L2F, or L2TP.

   What is required to provide roaming capability?  The following list
   is a first cut at defining the requirements for successful roaming
   among an arbitrary set of ISPs:

      Phone number presentation
      Phone number exchange
      Phone book compilation
      Phone book update
      Connection management
      Authentication
      NAS Configuration/Authorization
      Address assignment and routing
      Security
      Accounting

   In this document we review existing roaming implementations,
   describing their functionality within this framework.  In addition to
   full fledged roaming implementations, we will also review
   implementations that, while not meeting the strict definition of
   roaming, address several of these problem elements. These
   implementations typically fall into the category of shared use
   networks or non-IP dialup networks.

3.1.  Terminology

   This document frequently uses the following terms:


   home ISP  This is the Internet service provider with whom the user
          maintains an account relationship.


   local ISP This is the Internet service provider whom the user calls
          in order to get access. Where roaming is implemented the local
          ISP may be different from the home ISP.


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






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   shared use network
          This is an IP dialup network whose use is shared by two or
          more organizations.  Shared use networks typically implement
          distributed authentication and accounting in order to
          facilitate the relationship among the sharing parties. Since
          these facilities are also required for implementation of
          roaming, implementation of shared use is frequently a first
          step toward development of roaming capabilities.  In fact, one
          of the ways by which a provider may offer roaming service is
          to conclude shared use agreements with multiple networks.
          However, to date the ability to accomplish this has been
          hampered by lack of interoperability among shared use
          implementations.

   non-IP dialup network
          This is a dialup network providing user access to the member
          systems via protocols other than IP.  These networks may
          implement phone book synchronization facilities, in order to
          provide systems, administrators and users with a current list
          of participating systems.  Examples of non-IP dialup networks
          supporting phone book synchronization include FidoNet and
          WWIVnet.

4.  Global Reach Internet Consortium (GRIC)

   Led by a US-based Internet technology developer, AimQuest
   Corporation, ten Internet Service Providers (ISPs) from the USA,
   Australia, China, Japan, Hong Kong, Malaysia, Singapore, Taiwan, and
   Thailand formed the Global Reach Internet Connection (GRIC) in May,
   1996.  The goals of GRIC were to facilitate the implementation of a
   global roaming service and to coordinate billing and settlement among
   the membership.  Commercial operation began in December of 1996, and
   GRIC has grown to over 100 major ISPs and Telcos from all over the
   world, including NETCOM, USA; KDD and Mitsubishi, Japan; iStar,
   Canada; Easynet, UK; Connect.com, Australia; Iprolink, Switzerland;
   Singapore Telecom; Chunghwa Telecom, Taiwan; and Telekom Malaysia.
   Information on GRIC is available from http://www.gric.net/.

   In implementing their roaming service, GRIC members have chosen
   software developed by AimQuest. AimQuest Corporation's roaming
   implementation comprises the following major components: the
   AimTraveler Authentication Server (AAS), the AimTraveler Routing
   Server (ARS), and the AimQuest Internet Management System (AIMS),
   software designed to facilitate the billing process. Information on
   the AimQuest roaming implementation is available from
   http://www.aimquest.com/.





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   The AimTraveler Authentication Server (AAS) runs at each member ISP
   location, and handles incoming authentication requests from NAS
   devices and other AASes. The AimTraveler Routing Server (ARS) can run
   anywhere.  A single routing server can be used where centralized
   routing is desired, or multiple routing servers can be run in order
   to increase speed and reliability or to gateway to networks of
   particularly large partners.

   The first version of the AimTraveler software, deployed by AimQuest
   in May, 1996, supported direct authentication between members of the
   roaming consortium, but as GRIC grew, management of the relationships
   between the authentication servers became a problem. In August. 1996,
   AimQuest began development of the AimTraveler Routing Server (ARS) in
   order to improve scalability.

   The routing server is comprised of two elements: The Central
   Accounting Server and the Central Routing Server.  The Central
   Accounting Server collects all the roaming accounting data for
   settlement.  The Central Routing Server manages and maintains
   information on the authentication servers in the roaming consortium.
   Adding, deleting, or updating ISP authentication server information
   (e.g. adding a new member ISP) may be accomplished by editing of a
   configuration file on the Central Routing Server. The configuration
   files of the AimTraveler Authentication Servers do not need to be
   modified.

   The AimTraveler Authentication and Routing Servers are available for
   various UNIX platforms. Versions for Windows NT are under
   development.  The AimTraveler Authentication Server supports both the
   UNIX password file and Kerberos.

   The AimQuest Internet Management System (AIMS) is designed for large
   ISPs who need a centralized management system for all ISP operations,
   including sales, trouble-ticketing, service, and billing.  AIMS
   produces usage and transaction statement reports, and includes a
   settlement module to produce settlement/billing reports for the
   roaming consortium members.  Based on these reports, the providers
   charge their ISP/roaming customers, and pay/settle the roaming
   balance among the providers.  AIMS currently runs on
   Sun/Solaris/Oracle. A version for Windows NT and SQL Server is
   expected to become available in Q4 1996.

4.1.  Phone number presentation

   Currently there are two principal methods by which GRIC users can
   discover available phone numbers: a Web-based directory provided by
   the GRIC secretariat, and a GRIC phone book client on the user PC
   with dialing capability.



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4.1.1.  Web based directory

   A directory of GRIC phone numbers is available on the GRIC home page,
   http://www.gric.com/.  The list of numbers is arranged by country and
   provider. For each provider within a country, this directory,
   provided in the form of a table, offers the following information:

      Provider address, voice phone and fax
      Customer support phone number
      Provider domain name
      Primary Domain Name Server
      Secondary Domain Name Server
      Dial-up IP Address
      News server
      Web page
      POP phone numbers (i.e. 1-408-366-9000)
      POP locations (i.e. Berkeley)
      Proxy addresses
      Dialer configuration

   In order to discover phone numbers using the Web-based directory, it
   is expected that users will be online, and will navigate to the
   appropriate country and provider. They then look up the number and
   insert it into the AimQuest Ranger dialer.

4.1.2.  GRIC phone book client

   The GRIC phone book client software provides for phone book
   presentation as well as automated updating of phone numbers.  The
   GRIC phone book includes a list of countries, states, cities and
   area/city codes, as well as detailed provider information, including
   the cutomer support phone number, and Internet server configuration
   info.  The Phone book, developed with Java, is available for download
   from the AimQuest Web site:

     http://www.aimquest.com/dialer.html

4.2.  Phone number exchange

   GRIC members submit information both about themselves and their POPs
   to the GRIC secretariat, which is run by AimQuest. The GRIC
   secretariat then compiles a new phone book and provides updates on
   the GRIC FTP and Web servers.

   GRIC users then download the phone numbers either in Windows .ini
   file format or in HTML.





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4.3.  Phone book compilation

   GRIC phone books are compiled manually, and represent a concatenation
   of available numbers from all the members of the roaming consortium,
   with no policy application.  As new POPs come online, the numbers are
   forwarded to GRIC, which adds them to the phone book servers.

4.4.  Phone book update

   Phone numbers in the GRIC phone book client are updated automatically
   upon connection.  The AimTraveler server includes an address book
   which contains the phone numbers of all the roaming consortium
   members.

4.5.  Connection management

   The AimTraveler software supports SLIP and PPP, as well as PAP and
   CHAP authentication.

4.6.  Authentication