[ILUG] Re: [IIU] volunteers wanted for IIU survey

[Justin Mason]

Alex French said:

> >I've written a Perl script which will allow us to do a rudimentary survey
> >of Irish ISPs -- download it, run it and it will report PPP throughput
> >rates back to the IIU server. It should work OK on both Windows and UNIX
> >platforms (tested with Red Hat Linux but should be OK).
> 
> Don't mean to be critical -- I agree with what you're trying to do -- 
> but a quite scan through the code seems to indicate that it neglects 
> factors such as modem speed and MTU/MRU settings. These can make a 
> HUGE difference to connection performance. Also, I'm not exactly sure 
> what the data will tell you that will be of use. If I log on and sit 
> idle for 30 mins, will it show a bad throughput?

It does neglect MRU/MTU settings, modem speed, latency, and number of dial
attempts before a connection is established; mostly these are neglected
because I'm not sure how to get that data portably or just haven't done it
yet...

(also I'm not entirely clear how the MTU thing will work, I thought that
was a missing feature in MS TCP/IP from Windows 95, and modern TCP/IP
impls support MTU discovery?  That's what I was assuming anyway.)

The data format is extensible to support these anyway, so they can be
added if we can work out how to measure them without impinging on the user
too much.

But the main idea is that it samples the PPP statistics every 5 seconds,
and therefore can be used to get an idea of the peak throughputs for
bursts of traffic on that PPP session.  From that, a rough idea of the
highest data rate can be correlated to the ISP.

The lower data rates need to be thrown away of course, as they can result
from inactivity, telnet sessions, small pages, etc.

Brendan:  http://www.activestate.com/ActivePerl/download.htm is the URL
for perl on Windows ;) I've updated the page accordingly.

--j.