[Battlemesh] Session about multi-homed IPv6 mesh networks and auto-configuration

Juliusz Chroboczek jch at pps.univ-paris-diderot.fr
Tue Apr 19 18:02:11 CEST 2016

>> Hncp also wants to assign those real addresses to itself, and doesn't
>> cope with p2p assignment in the spec (tho julius extended it to /128s
>> I think)

> I'm still in the process of understanding hncp. What do you mean by p2p
> assignment exactly?

See Sections 5.1 and 6.1 of RFC 7788.  HNCP allows two kinds of assignment:

  - for "Internal" and "Guest" interfaces, it assigns a /64 (or an IPv4
    /24) to the link;

  - for "Ad Hoc" and "Leaf" interfaces, it assigns a /64 (or a /24) to the
    interface (which can result in multiple /64 for the link).

What Dave refers to is that a /64 is wasteful in a mesh network, so shncpd
extends this with a "Mesh" interface type that assigns a /128 (or a /32
for IPv4) to each interface.

>> I am actually not huge on global reachability for internal routers and
>> would prefer ULAs,

HNCP also allows assigining addresses to interfaces (Section 6.4), and
both implementations do that.  Dave happens to like unnumbered links (I
don't), and making address assignment optional is easy and doesn't violate
the spec, but it will require adding a config file parser to shncpd.

>> maybe grabbing a real ipv6 address for long enough to get an update,
>> that's it.

There's no need to temporarily assign addresses to unnumbered links, both
HNCP and Babel use link-local addresses for control traffic.

-- Juliusz

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