Re: [B.A.T.M.A.N.] two-radio nodes and alternative next hop

Axel Neumann
2008-04-23T07:54:37Z

Hey,

> > But according to the debug output there is a direct link to x.x.4.165/24
> > (which I guess has broadcast address of x.x.4.255) and therefore the two
> > interfaces should not see each other!!??
>
> there are direct links always only in the according /24 netrange,
> because they are on different channels/ssids, so .3.160 and .4.1 cannot
> "see" each other.
> Note, NO .4.x node cannot see ANY .3.x node, even if they
> would be on the same channel/ssid!
Are you also specifying the bssid? Because in order to define different
cells in an ad-hoc network the ssid is almost useless in most adhoc
implementations. THe BSSID is much more important!
(E.g. use kamikaze-etc/config/wireless style: option bssid 44:ca:ff:ee:ba:be
or the command-line-style: iwconfig wlan0 ap 44:ca:ff:ee:ba:be )

Anyway, you mean a debug output on 3.16 like the following can not be correct?
Neighbor outgoingIF bestNextHop brc (rcvd knownSince lseq lvld rid sid ) [ viaIF RTQ RQ TQ]..
172.19.4.165 wlan0:bmx 172.19.4.165 55 ( 84 0:00:28:03 9777 1 1 4 ) [ wlan0:bmx 46 76 60]

Sorry for being stubborn: what makes you so sure that they cannot see each
other or that the driver does not mix things up?

At least from the madwifi driver (in ad-hoc mode) I know that it tends to
ignore its assigned *bssid* and channel and switches back and forth between the
assigned one and others.

Sometimes the driver hangs on a wrong bssid and
channel, forwards the wrong IP packets, and cannot receive any packets from
its originally assigned bssid/channel.

One way to verify this would be to run a tcpdump on interface 3.160/wlan0 and
see if it ever tracks a batman packet with a src address of e.g. 172.19.4.165

> i'll make some more logs when .3.137 is back up
ok.

ciao,
axel