[Babel-users] Question about AHCP

[Juliusz Chroboczek]

> If I got the README file right every node in a mesh needs to run AHCP in 
> client mode and you can install any number of AHCP-servers.

Yes.

(Just to be pedantic: a mesh node can also be configured statically, in
which case it only needs to run ahcpd in forwarder mode.)

> Every server needs it's own IP range which cannot be shared with other AHCP-
> servers.

Yes, for IPv4 stateful configuration.

For IPv6 stateless configuration, it is okay if all servers announce the
same prefix.

> Does this mean I have to reconfigure the olsr AHCP-servers to add more AHCP-
> servers to the net, because they must give away some of their IPs ?

For IPv4 stateful configuration, yes, that's the case.

> What happens when one AHCP-server is dropping of the net ? Do every client of 
> it's IP range gets a new address from another servers IP range ?

Yes, but only after trying really hard to contact the original server.

Suppose a client C has been configured by server S1.  A few minutes
before its lease expires, C will try to contact S1 using unicast to
renew its lease.  If that fails, after a few minutes it will assume that
something bad has happened to routing, and it will try to contact S1
using flooding.  If that still fails, it will try to contact any server
using flooding.

                                        Juliusz