Internet Info 1997 December/Internet_Info_CD-ROM_Walnut_Creek_December_1997.iso/drafts/draft_s_z/draft-yamamoto-ipv6-over-p2p-atm-00.txt

Text File | 1997-09-22 | 12KB | 356 lines

Internet-Draft                                       K. Yamamoto (NAIST)
                                                       K. Cho (Sony CSL)
Expires in six months                                 Y. Inoue (Fujitsu)
                                                      H. Esaki (Toshiba)
                                                   Y. Atarashi (Hitachi)
                                              A. Hagiwara (Bay Networks)

                                                         September, 1997

          IPv6 over Point-to-Point ATM Link
          <draft-yamamoto-ipv6-over-p2p-atm-00.txt>

Status of this Memo

    This document is an Internet-Draft. 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
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    To learn the current status of any Internet-Draft, please check the
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    (Europe), ftp.isi.edu (US West Coast), or munnari.oz.au (Pacific
    Rim).

Abstract

    This memo defines a communication mechanism to exchange both IPv6
    unicast and multicast packets over an ATM network used as a
    point-to-point link.

1. Introduction

    ATM is now one of the most popular link-layer technologies in the
    Internet. Typical usage of ATM is categorized as follows:

        (1) Broadcast network such as LAN emulation(LANE)
        (2) Non-Broadcast Multiple Access(NBMA) networks
        (3) Point-to-point networks

    This memo discusses a communication mechanism for an IPv6[IPV6] over
    a point-to-point ATM link(3). One of applications of ATM is a fat
    pipe typically found in backbone networks.

    This memo defines IEEE 802.2 logical link control(LLC) headers for
    IPv6 over a point-to-point ATM link. The default of MTU size of
    point-to-point ATM and a mechanism to generate an interface
    identifier are also specified.


YAMAMOTO                                                        [Page 1]

Internet Draft               IPv6 over ATM                September 1997

2. Scope of This Memo

    Throughout this memo, the term "point-to-point ATM link" means that
    one virtual circuit(VC) is established between two nodes and the VC
    can be accessible through one logical network interface. This link
    is abstracted as a serial link to IPv6. It is not our intention to
    recommend that ATM be used exclusively for point-to-point networks.

    In this memo, ATM Adaptation Layer 5(AAL5)[ATM-ENCAP] is assumed to carry
    IPv6 packets over ATM. Both IPv6 unicast and multicast packets are
    delivered only to the opposite end of the point-to-point ATM link.

    Please note that point-to-point ATM link here is not a special case
    of NBMA(2). While NBMA requires a special mechanism for multicast, a
    point-to-point ATM link here does not require it.

    There is strong demand to implement an IPv6 network over a
    point-to-point ATM link without such a special mechanism. So, it is
    highly desirable to define LLC headers of IPv6 over a point-to-point
    ATM link for inter-operability.

3. Standard Keywords

    This memo uses terms which are in capital letters. When the terms
    "MUST", "SHOULD", "MUST NOT", "SHOULD NOT", and "MAY" appear
    capitalized, they are being used to indicate particular
    requirements, whose definitions are found in [KEYWORDS].

4. IPv6 packet encapsulation

    LLC encapsulation SHOULD be used to exchange IPv6 packets over a
    point-to-point ATM link. Null encapsulation SHOULD NOT be used for
    IPv6 packets since it is very likely that both IPv6 and IPv4 are
    used on a point-to-point ATM link at the same time.

    0x86DD is assigned for the EtherType of IPv6[ETHER], so this memo
    chooses 0x86DD as the Protocol Identifier(PID) according to
    [ATM-ENCAP]. The encapsulation for both IPv6 unicast and multicast
    on a point-to-point ATM link is defined as follows:

               +-------------------------------+
               |       LLC 0xAA-AA-03          |
               +-------------------------------+
               |       OUI 0x00-00-00          |
               +-------------------------------+
               |       PID 0x86-DD             |
               +-------------------------------+
               |             .                 |
               |       IPv6 packet             |
               |             .                 |
               +-------------------------------+




YAMAMOTO                                                        [Page 2]

Internet Draft               IPv6 over ATM                September 1997

5. MTU size

    The default MTU size for IPv6 over point-to-point ATM SHOULD be 9180
    octets according to [AAL5-MTU]. Values other than the default MAY be
    used.

    An automatic negotiation mechanism for the MTU is not defined in
    this memo. It is not usually necessary on ATM point-to-point links
    as long as same MTU value is correctly configured for each end of
    nodes and if Path MTU Discovery is used for off link communication.

    However, it is useful to provide a manual configuration mechanism of
    MTU in certain cases. For example, consider that a host and a router
    are connected with a point-to-point ATM link and the router is also
    attached to a LAN whose MTU is smaller than 9180. To prevent Path
    MTU Discovery triggered by the host, an administrator may wish to
    configure the MTU of the ATM interface to the smaller one in the
    router. This value will be announced to the host via Router
    Advertisements(RA) through the point-to-point ATM link then the host
    will adjust its MTU for the link.

6. Interface Identifier

    An interface for a point-to-point ATM link MUST have a 64 bit
    interface token for IPv6. It MUST be unique within the link. The
    interface token SHOULD be generated according to the following
    steps:

    (A) If the ATM interface has an EUI 64 bit MAC address, generate an
        interface identifier with it according to "Links or Nodes with
        EUI-64 Identifiers" in Appendix A of [AARCH].

    (B) If the ATM interface has an IEEE 802 48 bit MAC adddress,
        generate an interface identifier with it according to "Links or
        Nodes with IEEE 802 48 bit MAC's" in Appendix A of [AARCH].

    Note: A node may have multiple virtual interfaces on a single
    physical ATM interface. Such a node may generate the same interface
    identifier for the virtual interfaces, however, it is not a problem
    since interface identifier is not necessarily unique on the node.

    (C) If an EUI 64 bit MAC address is available anywhere on the node,
        generate an interface identifier with it according to "Links or
        Nodes with EUI-64 Identifiers" in Appendix A of [AARCH].

    (D) If an IEEE 802 48 bit MAC adddress is available anywhere on the
        node, generate an interface identifier with it according to
        "Links or Nodes with IEEE 802 48 bit MAC's" in Appendix A of
        [AARCH].

    (E) If an IEEE global identifier is not available, a different
        source of uniqueness should be used. For example, a suggested
        source of uniqueness is machine serial numbers. If such a source
        is available, generate an interface identifier with it according

YAMAMOTO                                                        [Page 3]

Internet Draft               IPv6 over ATM                September 1997

        to "Links with Non-Global Identifiers" in Appendix A of [AARCH].

    (F) If a good source of uniqueness cannot be found, generate an
        interface identifier with a random number according to "Links
        with Non-Global Identifiers" in Appendix A of [AARCH].

7. Neighbor Discovery

    It is required to implement NDP[NDP] functions on a typical
    point-to-point link defined in [NDPP2P].

8. Relationship with PPP

    This memo is one of the current simple solutions. PPP[PPP] is a more
    advanced solution with more features and subsequently needs more
    resources. Currently, the only feature provided by PPP which is not
    covered by this memo is Maximum Receive Unit (MRU). Duplicated Token
    Discovery is possible by Duplicated Address Detection.

    This memo provides an enough mechanism for current several
    well-managed and relatively static ATM environments. IPv6 over PPP
    over point-to-point ATM link may be used in the future if
    less-managed and/or more dynamic IPv6 on ATM circumstances are
    needed and/or more useful configuration options are defined for it.

9. Security Consideration

    It is believed that this memo does not introduce new security
    problems to IPv6.

References

    [AAL5-MTU] R. Atkinson, "Default IP MTU for use over ATM AAL5", RFC
        1626, 1994.

    [AARCH] R. Hinden and S. Deering "IP Version 6 Addressing
        Architecture", Internet-Draft,
        <draft-ietf-ipngwg-addr-arch-v2-02.txt>, 1997.

    [ATM-ENCAP] J. Heinanen, "Multiprotocol Encapsulation over ATM
        Adaptation Layer 5", RFC1483, 1993.

    [ETHER] M. Crawford, "Transmission of IPv6 Packets over Ethernet
        Networks", currently draft-ietf-ipngwg-trans-ethernet-02.txt.

    [EUI64] "64-Bit Global Identifier Format Tutorial",
            http://standards.ieee.org/db/oui/tutorials/EUI64.html.

    [IPV6] S. Deering and R. Hinden, "Internet Protocol, Version 6
        (IPv6) Specification", RFC 1883, 1996.

    [KEYWORDS] S. Bradner, "Key words for use in RFCs to Indicate
        Requirement Levels", RFC 2119, March 1997.


YAMAMOTO                                                        [Page 4]

Internet Draft               IPv6 over ATM                September 1997

    [NDP] T. Narten, E. Nordmark, and W. Simpson, "Neighbor Discovery
        for IP Version 6 (IPv6)", Internet-Draft,
        <draft-ietf-ipngwg-discovery-v2-00.txt>, 1997.

    [NDPP2P] Preparing.

    [PPP] Dimitry Haskin and Ed Allen, "IP Version 6 over PPP",
        Internet-Draft, <draft-ietf-ipngwg-ipv6-over-ppp-02.txt>, 1997.

Author's Address

    Kazuhiko YAMAMOTO
    Graduate School of Information Science
    Nara Institute of Science and Technology(NAIST)
    8916-5 Takayama, Ikoma 630-01 JAPAN

    Phone: [phone]
    FAX:   [phone]
    EMail: [e-mail]

    Kenjiro CHO
    Sony Computer Science Laboratory Inc.
    3-14-13 Higashi-Gotanda, Shinagawa-ku 141 JAPAN

    Phone: [phone]
    FAX:   [phone]
    EMail: [e-mail]

    Yoshinobu INOUE
    Fujitsu Limited
    4-1-1 Kamikodanaka, Nakahara-ku, Kawasaki 211-88 JAPAN

    Phone: [phone]
    FAX:   [phone]
    EMail: [e-mail]

    Hiroshi ESAKI
    Computer and Network Product Division, Toshiba Corporation
    Suite 19A, 1-1-1 Shibaura, Minato-ku 105-01 JAPAN

    Phone: [phone]
    FAX:   [phone]
    EMail: [e-mail]

    Yoshifumi ATARASHI
    Office Systems Division, Hitachi, Ltd.
    810 Shimoimaizumi, Ebina-shi 243-04 JAPAN

    Phone: [phone]
    FAX:   [phone]
    EMail: [e-mail]

    Atsushi HAGIWARA
    Bay Networks K.K.

YAMAMOTO                                                        [Page 5]

Internet Draft               IPv6 over ATM                September 1997

    28th SHIROYAMA JT MORI BLDG.
    4-3-1, Torano-mon, Minato-ku 105 JAPAN

    Phone: [phone]
    FAX:   [phone]
    EMail: [e-mail]

















































YAMAMOTO                                                        [Page 6]

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