Technical Summary
This document update the Babel routing protocol to support
announcing routes to an IPv4 prefix with an IPv6 next-hop. This
makes it possible for IPv4 traffic to flow through interfaces that
have not been assigned an IPv4 address. Since an IPv6 next hop can
use an IPv6 link-local address that is autonomously configured, the
use of such routes enables a mode of operation where the network
core has no statically assigned IP addresses.
Working Group Summary
The Babel WG was enthusiastic about this update to the Babel
protocol. Things were moving along when the group hit the speed
bump of what IPv4 source address to use when a v4-via-v6 Babel
router generates a v4 ICMP message. It took a little while to
resolve that resulting in the current specification which includes
use of the IPv4 dummy address if no other source of an IPv4 address
is available on the router. Based on the mailing list and WG
meetings, there is strong consensus for the draft.
Document Quality
This a reasonably short document of high quality. v4-via-v6 has
been implemented in babeld but not merged into the mainline source
yet. It has not yet been implemented in BIRD but the maintainer
has indicated their intention to do so. (The use of the IPv4 dummy
address when generating a v4 packet with no v4 addresses configured
has been submitted for inclusion in the Linux kernel.)
Personnel
Document Shepherd: Donald Eastlake
Area Director: Martin Vigoureux