Babel is a loop-avoiding distance vector protocol that has good
provisions for dynamically computed metrics and remains robust even in
the presence of metric oscillations and failure of transitivity. Babel
has seen some production deployment, notably in hybrid networks
(networks that combine classical, wired parts with meshy bits) and in
global overlay networks (networks built out of large numbers of
tunnels spanning continents). There exist three independent
implementations of Babel, all of which are open source.

The core of the Babel protocol is described in detail in RFCs 6126 and
7557, with RFC 7298 describing the security extensions, all of which
are Experimental Independent Stream RFCs. While
these RFCs have been useful (as indicated by the independent
reimplementations of Babel), a number of parties have expressed a
desire to have a new specification, which would clarify RFC 6126
according to the feedback provided by the independent
reimplementations and integrate the contents of RFC 7557.

The working group is will focus on what is needed to move
the Babel protocol to IETF Proposed Standard with IETF review.  Other
documents which are relevant to such consideration can also be
produced. Particular emphasis will be placed on work needed to meet
the needs for Proposed Standards, such as ensuring manageability and
strong security.

Work Items:

 - Produce a revision of RFC 6126 suitable for publication as a
 Proposed Standard, and work with the IESG for approval of same
   -- incorporate in the revision developments since RFC 6126
   -- resolve technical issues found by recent reviews and the working
      group discussions
   -- include in the base specification the extensibility work in
      rfc 7557
   -- consider any important changes based on experience with Babel to
 date.  This may include discussion of issues such as the size of the
 default metric.

 - Address security needs for BABEL.  This may include using the
   techniques in RF 7298, or other alternatives.  This may be by
   inclusion in the base spec or by normative reference to a
   separate proposed standard specification.  This is required as part
   of moving Babel to Proposed Standard.

 - Produce an applicability statement for publication as an
   informational RFC.  This is highly desirable in conjunction with
   moving Babel to Proposed Standard.

 - Address manageability of Babel, most likely by producing a YANG
   model for Babel consistent with other YANG models produced in the
   routing area.  This is required as part of moving Babel to Proposed
   Standard.

 - The working group may choose to publish an informational RFC on
   implementation experience with Babel, so as to enable future
   readers to better understand the state that drives this work and
   the experience driving changes.

 - The working group may choose to work on multicast aspects
   of Babel once the initial focus on Proposed Standard is met.

 - Coordinate with other working groups as need.

Thus, the working group will produce a proposed standard Babel
specification, either including or paired with a suitable security
specification for BABEL.  It will also produce a management model for
BABEL as a proposed standard RFC.  An applicability statement, and
possibly an experience document will be produced as informational
RFC(s).