[WLANware] DHCP servers and Subnets in Wireless Mesh Networks [Mesh Architecture]

[Antonio Quartulli]

Hello list, Naman,

On Tue, Nov 06, 2012 at 10:32:34AM -0500, Naman Muley wrote:
>    Me and a group of undergrads are working on establishing it for
>    the campus students for now. It will also act as a good research test bed
>    for wireless research. But my major aim is to provide seamless networking
>    inside the campus. 

[....]

>      I your end-users are able to run the mesh-software (OLSR or batman) on
>      their devices, then this is no problem, because they can choose a fixed
>      gateway with both applications. If they are just "stupid" dhcp clients,
>      then once again batman-adavanced as a layer 2 protocol would be the
>      reasonable choice.
> 
>    So we don't deal with IP handovers at all? Also, here's a major doubt that
>    i had. For technically a mesh network to exist, do all the client nodes
>    have to be mesh nodes / nodes-with-OLSRd ? But I guess, mesh networks can
>    also be used by ISPs to run a network of routers giving services to
>    clients right? 
> 

I think that for the two aforementioned points (seamless roaming and node vs.
client installation) batman-adv can be of help.
By being a layer 2 mesh networking protocol it handles roaming "automatically"
and in the last versions it also has support for seamless roaming (well, I think
it still has room for improvement). This will leave IP handoff/mobile IP out of
the game: the IP is kept regardless of the node you are attached to, the protocol
will do the rest while the client is simply moving around.


For what concerns the node vs. client issue, what you usually want is to install the
routing protocol on nodes only and let the clients be totally un-aware of the
mesh logics. Then you can have handhelds, cellphones or whatever connected to the
mesh.

This is possible with batman-adv, but also with layer3
protocols (like OLSRd or Babel): simply because the clients will become part
of the node network segment. However, as already mentioned before my reply, with
batman-adv the (mesh-un-aware) clients will have their DHCP packets re-routed in
a smart way so to choose the best (from the batman-adv metric point of view)
DHCP server. In case of a layer 3 protocol, each node should also run the DHCP
server, unless you think to some a bit more complex solutions.


Cheers,

-- 
Antonio Quartulli

..each of us alone is worth nothing..
Ernesto "Che" Guevara
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