Softwires (softwire)

Last Modified: 2008-08-21

Additional information is available at tools.ietf.org/wg/softwire

Chair(s):

  • Alain Durand <alain_durand@cable.comcast.com>

  • David Ward <dward@cisco.com>

    Internet Area Director(s):

  • Jari Arkko <jari.arkko@piuha.net>
  • Mark Townsley <townsley@cisco.com>

    Internet Area Advisor:

  • Mark Townsley <townsley@cisco.com>

    Technical Advisor(s):

  • Xing Li <xing@cernet.edu.cn>

    Mailing Lists:

    General Discussion: softwires@ietf.org
    To Subscribe: softwires-request@ietf.org
    In Body: With a subject line: subscribe
    Archive: http://www.ietf.org/mail-archive/web/softwires/current/index.html

    Description of Working Group:

    The Softwires Working Group is specifying the standardization of
    discovery, control and encapsulation methods for connecting IPv4
    networks across IPv6 networks and IPv6 networks across IPv4 networks in
    a way that will encourage multiple, inter-operable implementations. For
    various reasons (financial or political), native IPv4 and/or IPv6
    transport may not be available in all cases, and there is need to
    tunnel
    IPv4 in IPv6 or IPv6 in IPv4 to cross a part of the network which is
    not
    IPv4 or IPv6 capable. Configured tunnels or softwires are suited for
    the
    inter-networking job. Non-interoperable tunneling mechanisms have been
    developed based on the RFC3053 tunnel broker concept, and in addition,
    standardized mechanisms like RFC2893, RFC2473, GRE, L2TP, etc.
    have been used in some scenarios. Other deployments use
    non-standardized, incomplete solutions. The lack of interoperable
    and/or
    standardized solution in that space has been noted in the v6ops WG
    scenario analysis.

    The focus of this WG is to define a softwire setup negotiation protocol
    and encapsulation to be used between a node and the corresponding
    softwire end-point. Softwire configuration includes two phases:
    softwire
    end point discovery and softwire set-up. The WG will attempt to reuse
    existing technologies as much as possible and if necessary, create
    additional building blocks. It is expected that existing encapsulations
    will be the starting point.

    In the softwire set-up phase, the initator and the ISP negotiate the
    parameters necessary to establish the softwire. Those include:

    - The encapsulation type: IPv4-over-IPv6 or IPv6-over-IPv4 with a
    possible intermediary layer (e.g. UDP). This encapsulation negotiation
    should be extensible to cover future methods of both unicast and
    multicast traffic.

    - How to obtain the IP addresses to use for the softwire end-points.
    This could be done with an out-of-band mechanism or directly negotiated
    at set-up phase.

    In the softwire end point discovery phase, the initiator gets a name or
    an IP address for the ISP-side end point of the softwire to establish.
    This phase is orthogonal to the set-up one.

    The initial milestone for this working group will be the set-up phase.
    This WG is not chartered to work on the discovery phase and a re-
    charter
    will be needed prior to undertaking such work; once the base work has
    been completed (or is well under way), WG may consider re-chartering to
    address discovery.

    The WG will reuse existing technologies as much as possible and will
    create additional building blocks when necessary.

    The WG is chartered to complete the following work items:

    1. Document problem statement and submit to IESG as Informational. If
    this problem statement cannot be written within the IETF process of
    rough concensus, then the following items will not be advanced.

    2. Document softwire encapsulation and control protocol usage for
    IPv4-over-IPv6 or IPv6-over-IPv4 with possible intermediary layer and
    submit the specification to the IESG for publication as a Proposed
    Standard.

    3. Develop the softwire MIB module and submit it to the IESG for
    publication as a Proposed Standard.

    Goals and Milestones:

    Jan 2006  Submit a problem statement to the IESG to be considered as an Informational RFC
    Jul 2006  Submit softwire encapsulation and control protocol to the IESG to be considered as a Proposed Standard
    Oct 2006  Submit softwires MIB to the IESG to be considered as Proposed Standard

    Internet-Drafts:

    Softwire Hub & Spoke Deployment Framework with L2TPv2 (95495 bytes)
    Softwire Mesh Framework (74485 bytes)
    Advertising an IPv4 NLRI with an IPv6 Next Hop (26623 bytes)
    Traffic Engineering Attribute (13281 bytes)
    BGP Encapsulation SAFI and BGP Tunnel Encapsulation Attribute (31493 bytes)
    BGP IPSec Tunnel Encapsulation Attribute (18256 bytes)

    Request For Comments:

    Softwire Problem Statement (RFC 4925) (49299 bytes)
    IETF Secretariat - Please send questions, comments, and/or suggestions to ietf-web@ietf.org.

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