2.3.20 Softwires (softwire)
NOTE: This charter is a snapshot of the 70th IETF Meeting in Vancouver, BC Canada. It may now be out-of-date.
Last Modified: 2006-02-22
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Xing Li <email@example.com>
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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
IPv4 in IPv6 or IPv6 in IPv4 to cross a part of the network which is
IPv4 or IPv6 capable. Configured tunnels or softwires are suited for
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
standardized solution in that space has been noted in the v6ops WG
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:
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
- 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-
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
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
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
No Request For Comments