[Babel-users] Questions on the "new" AHCP

[Juliusz Chroboczek]

Ciao Saverio,

> I'm trying to test (again) AHCP on OpenWRT.

Great.

> it was only IPv6, and it was completely stateless without server/clients.

That was AHCP 0.  It was a very clean and very robust protocol.

I later tried to generalise the AHCP 0 design to stateful configuration
(AHCP 0.5), and it turned out to be a complete mess and a fragile
protocol to boot.  Which is why we now have AHCP 1, which is not quite
as clean as AHCP 0, but much cleaner and more robust than AHCP 0.5.

AHCP 1 is a pure client/server protocol, and can work both statelessly
(for pure IPv6 networks) and statefully (for IPv4 or hybrid v4/v6 networks).

>  * support for IPv4 configuration
>  * ASCII configuration instead of the binary file

Yep, except that the configuration file parser is not quite implemented
yet.  So everything goes on the command line for now.  (You won't see
the command line if you use UCI, of course.)

> 1) AHCP is a stand alone program, so does not depend on olsr or babel,

That's right.

> 3) If I use AHCP to configure ONLY IPv6, then everything is stateless
> as in the old AHCP and I don't have to make a difference between
> server instances and client instances ?

No.  You still need to have at least one server, and the other nodes
need to be clients.  However, the protocol will operate statelessly,
meaning that the servers will only give out static information, they
won't keep state.

You do that by using the -6 flag, either on the client or on the
server.  (In other words -- there will be no IPv4 address assignment if
either the client doesn't request an IPv4 address, or if the server
doesn't give one out.)

Note however that currently pure stateless operation is only implemented
on the client side, the server will still need to have an IPv4 lease
directory (which will not be used).

> But this client server difference is also when using only IPv6 ?

Yes.

> 4) Il possible to use AHCP only IPv6 + OLSR IPv6 ?

Yes.

                                        Juliusz