[OLSR-users] network problems

[Andrew Hodel]

Just wanted to note something I have noticed.

In my testing, setting a link to 5.5M on each node actually shows more
bandwidth (iperf) then 11M.  This is direct, no hops and true on most
links.

In closer reading of rate settings and iwconfig it seems that rate
5.5M auto will use 5.5M and lower bitrates, yet I am not sure if 5.5M
fixed will user 5.5M and higher bitrates.  It seems there is no way to
set a fixed speed with iwconfig.

quote <>
For cards supporting multiple bit rates, set the bit-rate in b/s. The
bit-rate is the speed at which bits are transmitted over the medium,
the user speed of the link is lower due to medium sharing and
overhead.
You must append the suffix k, M or G to the value (decimal multiplier
: 10^3, 10^6 and 10^9 b/s), or add enough '0'. Values below 1000 are
card specific, usually an index in the bit-rate list. Use auto to
select the automatic bit-rate mode (fallback to lower rate on noisy
channels), which is the default for most cards, and fixed to revert
back to fixed setting. If you specify a bit-rate value and append
auto, the driver will use all bit lower and equal than this value.
endquote <>

At this point I have decided rate 5.5M fixed is best for me.


Andrew

On 6/19/05, Andrew Hodel <(spam-protected)> wrote:
> This is all I have found on the subject:
> http://64.233.187.104/search?q=cache:pwVvfEXsyRgJ:lion.cs.uiuc.edu/courses/cs497hou/mbw.ppt+packet+pair+bandwidth&hl=en&client=firefox
> &
> http://64.233.187.104/search?q=cache:ZkmvmlorR9QJ:pdos.csail.mit.edu/decouto/papers/hsu97bandwidth.pdf+bandwidth+routing&hl=en&client=firefox
>
>
> It seems we could start with a simple plugin designed only to measure
> bandwidth, then we can base routing on that later.
>
> I am willing to help any way I can.
>
>
>
> Andrew
>
>
> On 6/19/05, Holger Mauermann <(spam-protected)> wrote:
> > Andrew Hodel wrote:
> > > how do you measure bandwidth without a large stream being sent and
> > > measured every few seconds?  This would eat up your bandwidth while
> > > trying to figure it out.
> >
> > No. If I understand the papers about the Packet-Pair technique
> > correctly, only a few hundred bytes have to be send to the target! And
> > even if it adds an overhead of 1 kbps for each node I think it's worth
> > the traffic ;-)
> >
> > --
> > \-- Holger Mauermann
> >  \-- (spam-protected)
> >   \-- PGP Key Id: 0x8EA8C301
> >
>