Re: [B.A.T.M.A.N.] Batman advanced and internet gateways

[Marek Lindner <lindner_marek@yahoo.de>]

On Tuesday, July 06, 2010 23:46:36 Clemens John wrote:
> Okay I did this but I have some questions left:

No problem.  :)


> Does the DHCP server on the gateway need to distribute IP-Adresses?

The server should distribute IP addresses and a default route to itself. I'm 
not sure whether you will find a dhcp server which does not distribute IPs but 
default routes.


> If so I think they have to be distributet on the batman interface right?

Correct.


> Does the Batman advanced interface on the clients need to request an
> IP-Adress from the DHCP server or can I also set a static IP adress?

That depends on your needs. Any interface which is supposed to use the gateway 
feature has to run a dhcp client. If the batX interface on the client does not 
need it you can give it a static address. If you just want to define the IP 
address of a specific host you can also work with aliases / multiple IPs per 
interface.


> If the clients need to request an IP adress from the DHCP server, where is
> the difference between requesting an IP without Batman advanced and with
> Batman advanced? Does Batman advanced say from wich server to request the
> IP or which default route to choose?

Normal dhcp requests are broadcasted through the entire network. Every dhcp 
server that receives this request will answer. If the client receives multiple 
answers it depends on the implementation to choose its "favorite" dhcp server. 
Most clients simply use the first server that answered.
If you enable the gateway client this request will not be broadcasted but 
directly sent to the chosen gateway. The other dhcp servers will not receive 
this dhcp request.


> Sry for this question we just discussed this on the last community meeting
> and somebody wondered if this is the most beautiful way. Maybe it´s not
> but you are right there is no other way.

We had this layer2/layer3 discussion quite often and this is the compromise we 
managed to achieve. It only works when enabled and indirectly via dhcp. It is 
not "beautiful" but it works.  :)


> Okay but it will likely be usable without crashing right?

No, it should not crash. I'm using it on a daily basis without problems.


> How can I configure batman advanced in /etc/config/batman-adv to enable gw
> server/client mode?

Since it was not part of an official release it also is not supported by the uci 
scripts. You would have add it yourself.

Regards,
Marek