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, 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 RFC - 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.
Submit a problem statement to the IESG to be considered as an Informational RFC
Submit DS-lite RADIUS attribute document for Proposed Standard
Adopt DS-lite operational document as a Working Group document
Submit 6rd RADIUS attribute document for Proposed Standard
Submit GI DS-lite document for Proposed Standard
Adopt DS-Lite without NAT document as a Working Group document
Adopt DHCPv4 over tunnel document as a Working Group document
Adopt 6rd operational document as a Working Group document
Adopt Multicast extensions document as a Working Group document
Submit DS-lite operational document for Informational
Adopt stateless legacy IPv4 solution motivation document as a Working Group document
Submit DS-Lite without NAT document for Informational
Submit DHCPv4 over tunnel document for Proposed Standard
Submit Multicast extensions document for Informational
Submit 6rd operational document for Informational
Adopt 6rd MIB module document as a Working Group document
Adopt DS-lite MIB module document as a Working Group document
Adopt Mesh topology MIB module document as a Working Group document
Submit stateless legacy IPv4 solution motivation document for Informational
Adopt stateless legacy IPv4 specification document as a Working Group document
Submit stateless legacy IPv4 specification document for Proposed Standard
Submit 6rd MIB module document for Proposed Standard
Submit DS-lite MIB module document for Proposed Standard
Submit Mesh topology MIB module document for Proposed Standard