Re: [B.A.T.M.A.N.] Batman-Adv : Hops and Throughput with Collocated dual-radio

["Linus Lüssing" <linus.luessing@web.de>]

Hi Jack,

what is the throughput you get from B to C? What was the
throughput you got on the 2.4GHz link alone? Did you change to
2.4GHz on A-B or B-C?

Cheers, Linus


On Mon, Oct 14, 2013 at 09:26:41AM +0800, Zaki wrote:
> Hi Simon,
> 
> Thanks for your reply.  I am using omni antenna right now and what i
> got when i did an iPerf from A to C is only 20Mbps.  It looks like the
> throughput is cut to half (just like a single radio mesh).  Tried 2.4G
> frequency in one of the pair, had the same result too.  Anything in
> terms of setting of batman-adv i can look for?.
> 
> Rgds,
> Jack
> 
> On Sun, Oct 13, 2013 at 10:36 PM, Simon Wunderlich
> <simon.wunderlich@s2003.tu-chemnitz.de> wrote:
> > Hi Zaki/Jack,
> >
> > On Fri, Oct 11, 2013 at 11:11:04AM +0800, Zaki wrote:
> >> Hi,
> >>
> >> I am a newbie in batman-adv.  I got a question regarding Hops and
> >> Throughput, especially in regards with a collocated dual-radio device.
> >>  Hopefully somebody could offer some help here for me to fully
> >> understand batman-adv operation.  I have 3 devices, namely A, B and C.
> >>
> >> A is only having single radio (operating at Freq 5.20G in AdHoc mode).
> >>  Put this under bat0.  Bridge bat0 with eth0.
> >> B is having dual-radio (radio1 operates at 5.20G in AdHoc mode, radio2
> >> is at 5.24G in AdHoc mode). Put these under bat0. Bridge bat0 with
> >> eth0
> >> C is like A (single radio, operating at 5.24G in AdHoc mode). Put this
> >> under bat0.  Bridge bat0 with eth0.
> >>
> >> So, the wireless link will be like this :
> >>
> >> [A]::::::::::::::: [B(radio1)---B(radio2)]::::::::::::::::[C]
> >>
> >> 1) If i were to ping from A to C, how many hops is it considered?.  Is
> >> it 2 hops or 3 hops?.
> >
> > that would be two hops. One hop is considered traversing one link, and
> > you have two links here.
> >
> >> 2) If my Iperf TCP throughput from A to B is 40Mbps, what is the
> >> expected throughput of Iperf from A to C ?.
> >
> > That depends. If the links are not interferring, you should get approx.
> > the maximum of both link throughputs. So if one link is 30 mbit/s, the second
> > is 25 mbit/s, that whole path would yield 25 mbit/s - there might be tcp
> > effects further decreasing throughput (latency etc).
> >
> > However you use two frequencies adjacent to each other. If you use omni
> > antennas, expect a lot of interferences (even if the channels are not
> > overlapping). If you use directional antennas you should be fine.
> >
> > Cheers,
> >         Simon
> >
> >
> >>
> >> Thanks a lot.
> >>
> >> Jack.