about batman performance

I have used batman on my project for several months.It performs very well,stable especially!
But,actually,I am not satisfied with the performance of Batman.I found that the bandwidth would drop sharply with the wireless hop increase. Now I provide my test result here:

routerA and routerB is composed of compex wp543ahv mainboard (AR7161 platform) and two AR9220 wireless card.Firmware is Openwrt backfire. one card is working on 2.4G channel as AP mode,the other is working on 5G channel as mesh backbone
batman version:2.0
notebook1 and notebook2 is equiped with 802.11n usb wireless card which access to the AP mode card of routerA and routerB

channel 1 channel 36 channel 11
notebook1 --------------- routerA -------------- routerB -------------- notebook2

I use iperf to test bandwidth

notebook1 ----------- routerA    45Mbps 
routerA   ----------- routerB    46Mbps 
routerB   ----------- notebook2  45Mbps 

But the bandwidth between notebook1 and notebook2 remains 8Mbps bandwidth between notebook1 and routerB remain 18Mbps

So the conclution is that the bandwidth will be halfed with the 1 hop increase! right?

I also found that the interface alternating mode and bonding mode doesn't take effect

channel 1
routerA ------------------ routerB
channel 36

The test result is no difference whatever I configured alternating or bonding or just single radio

According to the batman official site, alternating or bonding mode would improve the performance compared with the single radio mode

looking forward somebody's help
highly appreciated!

Hello zb1981gm (btw, do you have a real name?),

What is batman version 2.0? We have batmand (layer 3), but I guess you are using batman advanced as you talk about bonding/interface alternating later. These have 0.X (for old releases) or 201X.Y.Z version schemes (since 2 years). Please clarify.

Have you compared this to static routing?

It should not, as different radio modules are used (and correctly tuned on different channels). However, you may have a limitation in your CPU power or something else.
You may want to try static routing to find this out.

To make bonding work, there are a few conditions:
* routers must be equipped with multiple radios which can connect to each other
* activate bonding (batctl bonding 1)
* make sure the transmit qualities are similar (check with batctl o), should not be more than a difference of 50

If everything is fine, you can get a boost of approx. 50%.

Yup, it should help. Alternating is not helping in your scenario as far as I understand (your mesh is only 1 hop long, as notebooks are connected via infrastructure mode). Bonding may help as described above.

best regards,
Simon

Hi zb981gm,

we had a (somewhat) similar performance issue with our setup some time ago. We found out that a setup of two n-Cards in a single room decrease performance heavily, if both cards are under load at the same time. Forcing the cards into b/g mode did not help, so changing the cards to b/g hardware solved the problem for us.

May had to do with those fallback window override issues some n-Cards have, but not sure. In general, don't expect too much of an performance increase with n-Hardware on a USB 2.0 interface.

May be worth a try to look at first before fiddling around with the protocol, IMHO.

- Wuchi

Am 06.12.2011, 10:01 Uhr, schrieb zb1981gm <[email protected]>: