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Document Charter Softwires WG (softwire)
Title Softwires
Last updated 2019-03-27
State Approved
WG State Concluded
IESG Responsible AD Éric Vyncke
Charter edit AD Éric Vyncke
Send notices to (None)

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
    For various reasons, native IPv4 and/or IPv6 transport may not be
    available in all cases, and there is a need to tunnel IPv4 in IPv6
    or IPv6 in IPv4 to cross a part of the network which is not IPv4 or
    IPv6 capable. The Softwires Problem Statement, RFC 4925, identifies
    two distinct topological scenarios that the Working Group will
    provide solutions for: "Hubs and Spokes" and "Mesh." In the former
    case (Hubs and Spokes), hosts or "stub" networks are attached via
    individual, point-to-point, IPv4 over IPv6 or IPv6 over IPv4
    softwires to a centralized Softwire Concentrator. In the latter case
    (Mesh), network islands of one Address Family (IPv4 or IPv6) are
    connected over a network of another Address Family via point to
    multi-point softwires among Address Family Border Routers (AFBRs).
    The Softwires Working Group will reuse existing technologies as much
    as possible and only when necessary, create additional protocol
    building blocks.
    For generality, all base softwires encapsulation mechanisms should
    support all combinations of IP versions over one other (IPv4 over
    IPv6, IPv6 over IPv4, IPv4 over IPv4, IPv6 over IPv6). IPv4/IPv6
    translation mechanisms, new addressing schemes, and block address
    assignments are out of scope. DHCP options developed in this working
    group will be reviewed jointly with the DHC Working Group.  RADIUS
    attributes developed in the Softwires Working Group will be reviewed
    jointly with the RADEXT Working Group.  The MIB Doctors directorate
    will be asked to review any MIB modules developed in the Softwires
    Working Group.  BGP and other routing and signaling protocols
    developed in this group will be reviewed jointly with the proper
    working groups and other workings that may take interest (e.g. IDR,
    L3VPN, PIM, LDP, SAAG, etc).
    The specific work areas for this working group are:
    1. Developments for Mesh softwires topology; the Mesh topology work
       will be reviewed in the L3VPN and IDR Working Groups
       - multicast
       - MIB module
    2. Developments for 6rd:
       - multicast
       - operational specification
       - RADIUS attribute for 6rd server
       - MIB module
       - Gateway-initiated 6rd (GI-6rd)
    3. Developments for Dual-Stack Lite (DS-Lite):
       - multicast
       - operational specification
       - RADIUS attribute for AFTR
       - proxy extensions; GI-DS-Lite; No NAT on AFTR
       - MIB module
    4. Developments for stateless legacy IPv4 carried over IPv6
       - develop a solution motivation document to be published as an
       - develop a protocol specification response to the solution
         motivation document; this work item will not be taken through
         Working Group last call until the solution motivation document
         has been published or approved for publication
    5. Finalize discovery and configuration mechanisms for a gateway to
       use DS-Lite or 6rd; these discovery and configuration mechanisms
       must take into a account other operating environments such as
       dual-stack and tunneling mechanisms not defined by the Softwires
       Working Group.  Development of new mechanisms will involve the
       DHC and/or V6OPS Working Groups as appropriate
  Other work items would require Working Group approval and rechartering.