[manet] Re: MANET WG Charter and MANET Internetworking

> -----Original Message-----
> From: Juliusz Chroboczek <[email protected]>
> Sent: Thursday, July 17, 2025 9:06 AM
> To: Templin (US), Fred L <[email protected]>
> Cc: Donald Eastlake <[email protected]>; manet <[email protected]>; [email protected]
> Subject: [EXTERNAL] Re: MANET WG Charter and MANET Internetworking
> 
> > Julien,
> 
> Julius.  Completely different emperors.

Juliusz, apologies for that typo - an unintentional mistake on my part.

> > we need to get out into the open what the alternatives are and what
> > their advantages or limitations are before we can settle on charter
> > text.
> 
> I'd expect things to happen the other way around (charter first, solutions
> later), but okay.

I think there is room to have both stateless and stateful autoconfiguration in
the charter - it might make everyone happy.

> > The two autoconfiguration alternatives are 1) stateless based on SLAAC,
> 
> SLAAC doesn't work with routers.  We've all tried, but it cannot possibly
> work.
>
> (There's no mechanism to break RA loops, so if a MANET router ever needs
> to send an RA, say to an attached stub network, you lose.  You can design
> all sorts of workarounds, such as those proposed by the SNAC group, but
> I personally find them brittle and distasteful.)

I used the term SLAAC in an imprecise way. I did not mean SLAAC per the letter
of the law of RFCs 4861/2 which involves RS/RA messaging. Rather I meant that
if a MANET router already has a statistically unique 8 octet quantity that it can
use as an interface identifier, and it discovers through some means a /64 prefix
owned by a current Internet access point, then it should be able to statelessly
put 8+8 together to form a unique and globally routable IPv6 address. If all
routers in the MANET did this, then there may be temptation to consider the
MANET as an IPv6 subnet - but the multihop nature of the MANET would make
it a "multilink subnet" and RFCs 4903 and 5942 would have to be consulted.

> > stateful based on DHCPv6
> 
> I'm fairly sure you need state, but I don't see how that entails DHCPv6.

Can we conceptualize an 8+8 address autoconfiguration scheme where
the only "state" is the MANET router's unique interface identifier and
the current set of IPv6 prefixes advertised by a current working set of
Internet access points? This information could be propagated to all
MANET routers by the MANET routing protocol.

> > Here again, an overlay multilink network interface is needed to
> > coordinate the multiple interfaces.
> 
> I must have missed a step.  Why is that required?

To give all MANET routers the appearance of being on-link with the current
set of Internet access points and each other even if they may be multiple
hops away in the MANET underlay. The alternative in the DHCPv6 case is to
have all MANET routers also act as DHCPv6 relay agents, but that might not
work so well in dynamic MANETs with rapidly changing topologies.

Thank you - Fred

> -- Juliusz

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