Re: [B.A.T.M.A.N.] Bad link quality if routers are connected by 2 interfaces

[Simon Wunderlich <sw@simonwunderlich.de>]

Hey Clemens,

> Am Montag, 4. November 2013, 11:28:20 schrieben Sie:
> > this is certainly not the expected behaviour. Are you building a bridge
> > loop by any chance? Please explain your configuration (batctl if, brctl
> > show, ...) and check if you have a high amount of broadcasts somehow.
> 
> Sorry for my late answer. I was busy during the week and didnt find the
> time to look into out setup in detail till now.
> 
> We have two wireless interfaces wlan0 and wlan0-1. We also have two
> ethernet interfaces eth0.1 and eth0.3 and one VPN interface ffolVPN.
> 
> The interfaces wlan0 and eth0.1 are the interfaces used for clients. They
> are bridged together with bat0:
> root@RosenplatzVPN:~# brctl show
> bridge name   bridge id                     STP enabled     interfaces
> br-mesh          8000.a0f3c15b54a6   no                    bat0
>                                                                            
>      eth0.1 wlan0
> 
> The interfaces wlan0-1 and eth0.3 are the interfaces we use for meshing
> with other routers in the same "mesh cloud". These are the interfaces both
> routers are connected by each other. The vpn interface ffolVPN is used to
> connect with outher "mesh clouds" but the two routers in this case are not
> connected by this interface. On the interfaces wlan0-1, eth0.3 and ffolVPN
> runs Batman advanced:
> root@RosenplatzVPN:~# batctl if
> eth0.3: active
> wlan0-1: active
> ffolVPN: active
> 
> To analyze the amount of broadcast traffic I did a tcpdump on the Batman
> interfaces wlan0-1 and eth0.3. For me there seems to be a big amount of
> broadcast traffic, but I don´t know the normal level of brodcasts so I
> can´t compare which amount is right and which is wrong. But maybe you can
> so I uploaded the files for you. You can analyze them using wireshark or
> some other tool:
> * https://dev.freifunk-ol.de/tcpdumps/eth0.3.dump
> * https://dev.freifunk-ol.de/tcpdumps/wlan0-1.dump
> 
> If you need more data just ask and I will try to provide it.

Thanks for the explanation and the dumps! I had a look at your dumps, but it 
doesn't look like a bridge loop - the number of broadcasts is normal. I don't 
have a clue yet where this behaviour comes from. I'd like to make a few more 
suggestions for debugging:

 * can you please make a debug log of batman-adv on the two nodes at the same 
time (batctl ll batman && batctl l > logfile.$hostname or something like this)

 * what are the MAC addresses of these two nodes?
As far as I see in the debug output, on one node there is:
 * Ethernet fa:d1:11:af:fd:15
 * WLAN fa:d1:11:af:fd:16

However, a2:f3:c1:5b:54:a6 is used as Ethernet source address for sending in 
both eth0.3 and wlan0-1 dumps. Is it possible that there is a mac address 
conflict?

Cheers,
    Simon