A good value of UPLOAD links for ADSL users
 

I am using gnut-0.4.xx on Linux as gnutella client and I have used Limewire too.

I think that the gnutella network wuold work much better if ADSL (or lower bandwidth) users would set max_uploads to 1.

Suppose I am sharing a 10MB file, and my outgoing bandwidth is 10kBps.
It would take 1000s to upload to one (the only) downloader, and then we both could serve that file to others.
While it would take 2000s to upload to two downloaders, and at the and the number of servers is three times than before.

Generally speaking, the number of servers that can share a given content obeys the law:

N=(1+L)**(t/(T*L))

Where L is the number of uploads running, T is the time necessary to complete a download when you are the only downloader and t is the observation window span (this assumes that all servers are always busy)

If you try and diagram the function above with for example t/T = 30 (let's say a 10MB file, and sharing at night), you'll see that the result for L=1 is well above (orders of magnitude) any other choice of the number of upward connections.

I would like to be warned is this is flawed.
If not, I would like ADSL users knew about it.

Stefano

you are forgetting that files can be resumed and maybe the guy only needs the last meg of the file from you.
if you leave your client on all the time its not a problem, I love to share! It's fun to see the RIAA get a kick in the ***.
for linux, go to freshmeat and get yourself a real client.

>You are forgetting that files can be resumed and maybe the guy only needs the last meg of the file from you

I'm not forgetting it.
When I write "a given content" I mean "any piece of any file".

The reason to set max_uploads to 1 (for low bandwidth users) can perhaps be explained better with an example:

Suppose I have a really hot file that, say ten, guys want as soon as possible.

And say that my outbound connection can upload that file in a time T (to one user).

I could allow ten uploads to those guys, who would get that file in a time 10T.

But I could allow only one outbound connection.
Then there would be a lucky guy that would get the file in a time T. At that time, there would be two servers, me and the other guy, so TWO other guys could get the file in a time 2T (T waiting and T downloading).
Then at time 2T there would be FOUR servers, and four other guys would get the file in time 3T (2T waiting and T downloading). Finally at time 3T we'll have EIGHT servers, and the last two guys
would get the file in time 4T (3T waiting, T downloading), with SIX spare servers.

I've seen that many DSL sharers allow TWO uploads.
This is anyway NOT GOOD, because then after 2T (time to complete those uploads), there are THREE
servers (the first and the two downloaders), while allowing only one upload gets FOUR at time 2T.

What I've written assumes that the download band is greater than the upload one, thus only for ADSL and 56k links. Those freaks having T1 or above will be happy with the default setup of most gnutella clients.


>For linux, go to freshmeat and get yourself a real client.

What do you mean "a real client"? gnut-0.4.xx IS IMO a REAL client, since you can see anytime what it is doing, can (obviously) resume downloads, can run as an unattended server and is open source too.

But you're forgetting that not everyone is uploading with max speed from you.
Suppose the lucky guy that gets the connection is the one with the slow dial in modem who does the upload with a speed below 2k. Then the upload will be done in a time >5T and all the time you are wasting 80% of your upload bandwidth.
And what if you have more than only one really hot file and the download began with that really big one. None would be able to get one of those cute tiny little files that otherwise could be spread all over the net before that first download is finished.

Gnut is a old client, there are better ones out there now.

>Gnut is a old client, there are better ones out there now.
[flame mode: on]
gnut-0.4.25 has been released about ten days ago. It fully implements the gnutella protocol 0.4 and the 'last' command is useful to see what's going on when talking to BearShare servants, that open an HTTP connection just to say they are busy.
[flame mode: off]


[begin quote: GreyFool]
But you're forgetting that not everyone is uploading with max speed from you. Suppose the lucky guy that gets the connection is the one with the slow dial in modem who does the upload with a speed below 2k. Then the upload will be done in a time >5T and all the time you are wasting 80% of your upload bandwidth. And what if you have more than only one really hot file and the download began with that really big one. None would be able to get one of those cute tiny little files that otherwise could be spread all over the net before that first download is finished.
[end quote]

You are right. Then maybe it would be fine if the servents did adapt max_uploads to the lowest number that uses full (that is more than .9x) upload bandwidth.
This might be useful for ANY gnutella network servent. I think this should be given a try.

Thank you.