Re: [B.A.T.M.A.N.] Replacing OLSRD with batman-adv?

[Simon Wunderlich <sw@simonwunderlich.de>]

Hello Travis,

> Hi Ladies and Gents,
> 
> I've built a three-node mesh network using cheap TP-Link TL-WDR3600
> routers. They can do simultaneous 5.8GHz and 2.4GHz. I use the 5.8 for
> the backbone links between the nodes, and 2.4 to clients. The nodes
> are running OpenWRT and OLSRD.
> 
> This system mostly works well, but there are a couple of problems with
> it that I'm wondering if batman-adv would solve or make easier to
> solve:
> 
> 1) The backbone links cannot be better protected than WEP, a
> limitation of OLSRD,
> 2) Gateway assignment is a manual process, which must be performed on
> every node in the mesh, referring to the single node connected to the
> WAN,
> 3) The manual gateway configuration of 2) prevents peer-to-peer
> communications between mesh clients,
> 4) Each node has its own /24 subnet. This causes problems when a
> device roams from one device's jurisdiction to another if the
> interface doesn't re-issue a DHCP request.
> 
> We're expanding the network, I've just bought another ten of these
> routers, and I'm going to spend some time assessing if batman-adv
> would be a better fit for our purposes. There will be a range of ios,
> android and windows devices connecting to the mesh.
> 
> My questions are as follows:
> 
> 1) Does batman-adv worth with WPA2 or better encryption?

you can use IBSS/RSN with wpa-supplicant, this is WPA2 encryption for Ad-Hoc. 
(BTW this would also work with olsr). It is available in recent kernels and 
OpenWRT trunk.

> 2) Must every client to a batman-adv mesh have a daemon installed?

No, that's not required.

> 3) Is it possible to separate different radio interfaces for different
> purposes? I.E. 5.8 for backbone, 2.4 for clients.

Yes, you can instruct batman-adv to only use the 5.8 GHz interface. Just add 
the interfaces you want batman-adv to use.

> 4) Can all nodes and clients on a mesh have an IP in the same subnet,
> solving some of the roaming problems caused by bad interface settings
> or drivers?

Yes, that's one of the strong points of batman-adv compared to Layer3 routing 
daemons. Just put a DHCP server somewhere in your network, bridge everything, 
and enjoy a Layer2 broadcast domain with only one subnet, just as you would 
use it in a LAN. We also support fast roaming, so you can maintain 
connectivity when changing Access Points with only minimal outages.

We have a lot of documentation, you can get started at:
https://www.open-mesh.org/projects/batman-adv/wiki/Quick-start-guide

if you have multiple gatways to the Internet check
https://www.open-mesh.org/projects/batman-adv/wiki/Gateways

Although this is not required if you only have one gateway.

Cheers,
    Simon