rfc3017.txt

最新的RFC

Network Working Group                                          M. Riegel
Request for Comments: 3017                                    Siemens AG
Category: Standards Track                                        G. Zorn
                                                           Cisco Systems
                                                           December 2000


                 XML DTD for Roaming Access Phone Book

Status of this Memo

   This document specifies an Internet standards track protocol for the
   Internet community, and requests discussion and suggestions for
   improvements.  Please refer to the current edition of the "Internet
   Official Protocol Standards" (STD 1) for the standardization state
   and status of this protocol.  Distribution of this memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (2000).  All Rights Reserved.

Abstract

   This document defines the syntax as well as the semantics of the
   information to be included in the phone book for roaming
   applications.  It comprises the information necessary to select the
   most appropriate ISP and to configure the host to get access to the
   network of the provider. The specification consists of a small set of
   required information elements and a variety of possible extensions.
   All data is specified in XML [5] (Extensible Markup Language) syntax
   leading to a concise XML DTD (Document Type Declaration) for the
   phone book.

Table of Contents

   1.  Introduction .............................................  3
   2.  Rationale for XML Usage ..................................  4
   3.  Specification of Requirements ............................  5
   4.  Value type notations for 'stronger' typing ...............  5
   5.  Container Element Definitions ............................  5
     5.1.  PhoneBook ............................................  5
      5.1.1.  phoneBook Attribute "name" ........................  6
      5.1.2.  phoneBook Attribute "version" .....................  6
     5.2.  POP ..................................................  7
      5.2.1.  pop Attribute "entryVersion" ......................  8
     5.3.  Setup ................................................  8
     5.4.  Support ..............................................  9
     5.5.  Provider .............................................  9



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   6.  Information Element Definitions .......................... 10
     6.1.  Information elements defined for the POP element ..... 10
      6.1.1.  Address ........................................... 10
       6.1.1.1.  address Attribute "family" ..................... 10
       6.1.1.2.  address Attribute "countryCode" ................ 11
       6.1.1.3.  address Attribute "areaCode" ................... 11
      6.1.2.  Media ............................................. 11
       6.1.2.1.  Modem Protocols ................................ 12
       6.1.2.2.  ISDN Protocols ................................. 12
       6.1.2.3.  ATM Protocols .................................. 13
       6.1.2.4.  Frame Relay Protocols .......................... 13
       6.1.2.5.  X.25 Protocols ................................. 13
      6.1.3.  Minimum Data Rate ................................. 14
      6.1.4.  Maximum Data Rate ................................. 14
      6.1.5.  POP Properties .................................... 14
      6.1.6.  Tunneling Protocols ............................... 15
      6.1.7.  Dialing Script .................................... 15
      6.1.8.  Pricing Information ............................... 16
      6.1.9.  City .............................................. 16
      6.1.10.  Region ........................................... 16
      6.1.11.  Country .......................................... 16
      6.1.12.  POP Setup ........................................ 17
      6.1.13.  POP Support ...................................... 17
      6.1.14.  POP Provider ..................................... 17
     6.2.  Information elements defined for the Setup element ... 17
      6.2.1.  DNS Server Address ................................ 17
      6.2.2.  NNTP Server Name .................................. 18
      6.2.3.  SMTP Server Name .................................. 18
      6.2.4.  POP3 Server Name .................................. 18
      6.2.5.  IMAP Server Name .................................. 18
      6.2.6.  WWW Proxy ......................................... 19
      6.2.7.  FTP Proxy ......................................... 19
      6.2.8.  Winsock Proxy ..................................... 19
      6.2.9.  Default Gateway Address ........................... 19
      6.2.10.  User Name Suffix ................................. 20
      6.2.11.  User Name Prefix ................................. 20
     6.3.  Information elements defined for the support element.. 20
      6.3.1.  Support Telephone Number .......................... 20
      6.3.2.  Support Email Address ............................. 21
     6.4.  Information elements defined for the provider element. 21
      6.4.1.  Provider Name ..................................... 21
      6.4.2.  Provider Icon ..................................... 21
      6.4.3.  Provider's World Wide Web URL ..................... 21
      6.4.4.  Provider's Main Email Address ..................... 22
      6.4.5.  Billing Inquiry Email Address ..................... 22
      6.4.6.  Further elements .................................. 22
   7.  Complete XML DTD for the roaming phone book .............. 22
   8.  Security Considerations .................................. 28



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   9.  IANA Considerations ...................................... 28
     9.1.  Registration of new attribute values ................. 29
     9.2.  Registration of new information elements ............. 29
   10.  References .............................................. 30
   11.  Appendix: Examples ...................................... 31
     11.1.  The most simple example ............................. 31
     11.2.  A more comprehensive example ........................ 31
   12.  Acknowledgments ......................................... 31
   13.  Authors' Addresses ...................................... 32
   14.  Full Copyright Statement ................................ 33

1.  Introduction

   Roaming applications depend on the delivery of information about
   provided services and the procedures to get connected to the network
   from the roaming consortium to the individual users as well as from
   the operators of the network access servers, normally the members of
   the roaming consortium, and the roaming consortium.

              "phone book"
    +------+    +--+
    |      |    |  ++
    | ISP1 | -- |   | --+
    |      |    +---+    \              "phone book"
    +------+              \   +------+
    +------+    +--+       \_ |      |     +--+      +------+
    |      |    |  ++         |      |     |  ++     |      |
    | ISP2 | -- |   | -->>--- |      | --- |   | ->> | USER |
    |      |    +---+       _ |      |     +---+     |      |
    +------+               /  |      |               +------+
    +------+    +--+      /   +------+
    |      |    |  ++    /    Roaming
    | ISP# | -- |   | --+    Consortium
    |      |    +---+
    +------+

   The roaming consortium assembles from the individual contributions of
   the providers belonging to the consortium a unified version of the
   phone book for usage by the customers.  Probably different groups of
   users get different versions of a phone book adapted to their
   particular needs.  Even users might generate different subsets
   especially suited to particular applications from the information
   received from the roaming consortium, e.g., retrieving only entries
   for a particular country or extracting all access points providing
   wireless connectivity.






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   Therefore it is desirable to define a highly portable and well formed
   structure of the phone book to enable easy generation and
   postprocessing.  Goals of this document include:

      - Creating a flexible, extensible and robust framework
        upon which to build a standard phone book;
      - Promoting a standard phone book format, to enhance
        interoperability between ISPs and roaming consortia as
        well as to enable automatic extraction of configuration
        data by a wide variety of devices;
      - Defining a compact structure containing the essential
        information for the roaming user, to allow for storage
        and easy update even on small devices.

   It is not intended by this document to create a plethoric solution,
   with phone book elements to fit every condition on earth, neither to
   define any kind of phone book update or transfer protocol.

2.  Rationale for XML Usage

   XML is rapidly becoming a standard format for data exchange between
   different applications also taking into account the transfer and
   access of data over the web.  XML is used as syntax for expressing
   the structure and content of a roaming phone book to enable
   widespread usage and access to many different kind of media (e.g.,
   paper, CDROM, www) using a widespread selection of access devices.
   Furthermore XML enables:

      - Extensibility
      - Flexibility
      - Integration with directories

   Extensibility is important because phone books are living documents;
   as such, it is unlikely that all the semantic requirements of
   arbitrary Internet service providers (ISPs) would be met by a fixed
   scheme, no matter how well thought out.  Phone book designers must be
   free to create new attributes in a well-understood fashion to meet
   changing business needs.

   Flexibility is required of the attribute definition syntax for many
   of the same reasons that semantic extensibility is necessary.  If we
   assume that phone book designers may need to define elements of
   arbitrary type, the syntax chosen must be able to represent these
   data objects cleanly.  Using XML for describing the data content of
   the phone book fits this bill nicely, since it can be used to
   unambiguously describe virtually any data type.





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   Integration with directories: although it is unlikely that phone
   books will be stored in the directory due to performance
   considerations, the creation of a XML DTD describing phone book
   content leaves that option open, with relatively little incremental
   effort required to implement it.

3.  Specification of Requirements

   In this document, the key words "MAY", "MUST, "MUST NOT", "optional",
   "recommended", "SHOULD", and "SHOULD NOT", are to be interpreted as
   described in [1].

4.  Value type notations for 'stronger' typing

   XML DTDs do not currently have capabilities for 'strong typing' of
   the content of elements.  The only type definition foreseen in the
   base specification is "#PCDATA", 'parsable character data'.  This
   might be sufficient and is used throughout this document to define
   elements containing information mainly aimed for interpretation by
   human beings.

   To enable a more concise description of the content of particular
   elements several value type notations are introduced.  This allows
   for a more detailed type description of the content of elements in
   cases where it seems to be desirable.

      <?xml version="1.0" encoding="UTF-8"?>

      <!-- Phone book value type notation declarations -->
      <!NOTATION FQDN PUBLIC "-//IETF/roamPhoneBook/NOTATION
      value Type Fully_qualified_domain_name">
      <!NOTATION IPADR PUBLIC "-//IETF/roamPhoneBook/NOTATION
      value Type IP_address">
      <!NOTATION B64JPG PUBLIC "-//IETF/roamPhoneBook/NOTATION
      value Type Base64_encoded_jpeg_image">
      <!NOTATION B64GIF PUBLIC "-//IETF/roamPhoneBook/NOTATION
      value Type Base64_encoded_gif_image">

5.  Container Element Definitions

5.1.  PhoneBook

   The phoneBook element is the basic container for phone book entries.
   It has two attributes, a phone book name and a phone book version
   number (applying to the phone book as a whole), and always contains
   one or more pop elements.  A phoneBook element may also contain
   multiple Setup, Support and Provider elements, if they are referenced
   to by more than one pop element.



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   Syntax:
      <!ELEMENT phoneBook (
            pop+,
            setup*,
            support*,
            provider*)>
      <!ATTLIST phoneBook
            name    CDATA   #REQUIRED
            version CDATA   #REQUIRED >

        phoneBook
      +-----------------------------------+
      | phoneBookName                (req)|
      | phoneBookVersion             (req)|
      | +-----------------------+         |
      | | pop                   |+   (req)|
      | +-----------------------+|        |
      |  + - - - - - - - - - - - +        |
      |                                   |
      | + - - - - - - - - - - - +         |
      | | setup                 |+   (opt)|
      | + - - - - - - - - - - - +|        |
      |  + - - - - - - - - - - - +        |
      |                                   |
      | + - - - - - - - - - - - +         |
      | | support               |+   (opt)|
      | + - - - - - - - - - - - +|        |
      |  + - - - - - - - - - - - +        |
      |                                   |
      | + - - - - - - - - - - - +         |
      | | provider              |+   (opt)|
      | + - - - - - - - - - - - +|        |
      |  + - - - - - - - - - - - +        |
      +-----------------------------------+

5.1.1.  phoneBook Attribute "name"

   The phoneBook attribute "name" is an arbitrary string assigned as an
   identifier for a phone book.

5.1.2.  phoneBook Attribute "version"

   The phoneBookVersion attribute is an integer representing the version
   of the phone book; it is a monotonically increasing counter which
   should be incremented each time the phone book is modified.  This
   element can be used by a server to help decide what (if any) actions
   are required to bring a client's phone book up to date.  For example,
   the client can, at connect time, send an update request to the server



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   including in the request the version number of its current phone
   book.  If the client's phone book version is not the same as the
   server's current phone book version, the server can easily take
   appropriate action, e.g., reply with a URL pointing to a file
   containing the differences between the client and server phone books.

5.2.  POP

   The pop element contains information elements relevant to individual
   network points of presence (POPs).  The required information elements
   are addrFamily, address, media and entryVersion.  The media element
   represents the media types supported by the POP, while the
   entryVersion element is a monotonically-increasing integer which
   should be incremented whenever the object is modified.

   The following information elements are currently defined for the pop
   element.  Additional information elements may be defined by IANA in
   future.

        POP
      +-----------------------------------+
      |  entryVersion                (req)|
      | +-------------------------+       |
      | | address                 |  (req)|
      | +-------------------------+       |
      |  media                       (req)|
      |  minBitsPerSecond            (opt)|
      |  maxBitsPerSecond            (opt)|
      |  "popProperties"             (opt)|
      |  "tunnelingProtocols"        (opt)|
      |  dialScript                  (opt)|
      |  pricingInformation          (opt)|
      | + - - - - - - - - - - - - +       |
      | | "location"              |  (opt)|
      | + - - - - - - - - - - - - +       |
      | + - - - - - - - - - - - - +       |
      | | "popSetup"              |  (opt)|
      | + - - - - - - - - - - - - +       |
      | + - - - - - - - - - - - - +       |
      | | "popSupport"            |  (opt)|
      | + - - - - - - - - - - - - +       |
      | + - - - - - - - - - - - - +       |
      | | "popProvider"           |  (opt)|
      | + - - - - - - - - - - - - +       |
      +-----------------------------------+






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   Syntax:

      <!ENTITY % popInformation
           "address,
            media+,
            minBitsPerSecond?,
            maxBitsPerSecond?,
            popProperty*,
            tunnelProto*,
            dialScript?,
            pricingInformation?,
            city?,
            region?,
            country?,
            (setup | setupPtr)?,
            (support | supportPtr)?,
            (provider |providerPtr)?">

      <!ELEMENT pop ( %popInformation; )>
      <!ATTLIST pop
            entryVersion   CDATA   #REQUIRED>

5.2.1.  pop Attribute "entryVersion"

   The entryVersion attribute is an integer representing the version of
   the POP object; it is a monotonically increasing counter which should
   be incremented each time the object is modified.  This attribute may
   be useful in merging and updating phone books.

5.3.  Setup

   The Setup element includes information elements which describe
   services which may change from provider to provider or even from POP
   to POP.  Some of the values contained in these information elements
   may be available by other means (e.g., DHCP), but others may not.

   The following information elements are currently defined for the
   Setup element.  Additional information elements may be defined by
   IANA in future.

   Syntax:

      <!ENTITY % setupInformation
           "dnsServerAddress*,
            nntpServerName*,
            smtpServerName*,
            popServerName*,
            imapServerName*,



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            wwwProxyServerName*,
            ftpProxyServerName*,
            winsockProxyServerName*,
            defaultGatewayAddress?,
            userNamePrefix?,
            userNameSuffix?">

      <!ELEMENT setup ( %setupInformation; )>
      <!ATTLIST setup