Re: netselect - choosing the best FTP server automatically
On Sat, Jun 27, 1998 at 09:39:26PM -0400, James R. Van Zandt wrote:
> Avery Pennarun <apenwarr@worldvisions.ca> writes:
> >Jason Gunthorpe wrote:
> >> My question is how can we build a single weighted score for each
> >> site? Let the user pick one of the top two or so. But how do you
> >> weight?
> >
> >Assuming that the packet loss and timing statistics were made more
> >reliable...
> >
> >I would say that packet loss and delay are of almost equal
> >importance, and hop count considerably less.
>
> I suggest:
> (1 - packet_loss) / average_delay
>
> If you multiplied this by the size of the packets, it would be
> approximately the bandwidth (bytes per second).
Unfortunately, packet loss causes a disproportionate amount of trouble; if I
miss 20% of packets, I don't get 80% of bandwidth. I get maybe 10% of
bandwidth because TCP starts fizzling out.
Hence my big mess of a math formula assigning packet loss and delay
approximately equal weighting. A 50% site with 10ms delay simply should
never win compared to a 90% site with 200ms delay.
IMHO... best thing to do is take a lot of results, transfer a file from each
of the "obviously better" hosts, and see what formula results in the closest
result :)
Have fun,
Avery
--
To UNSUBSCRIBE, email to deity-request@lists.debian.org
with a subject of "unsubscribe". Trouble? Contact listmaster@lists.debian.org
Reply to: