limited upstream bandwith in XP ?

[Igor Ybema]

I hope someone can help me with this one.

It seems Windows XP (pro) is somehow limiting the bandwith used per upstream
session to about 10% of the bandwith available.
First of all, I know about the 20% limiting with the QoS scheduler. But this
is something different. Let me explain:

I'm a network-administrator on a University so I know some things about
networks.
I've installed an FTP server on my XP machine (for example IIS-ftp or
serv-u). The machine has 100Mbit switched full-duplex. Downloading files
from this machine is going as fast as expected. F.e. downloading XP sp1
network install from Microsoft is going at a rate at about 25 Mbits/s.

The problem is when the XP machines needs to send. So while it is uploading
to, or another machine is download from it. The 'upstream' part. But ONLY
when it needs to send for at least more than one hop. And when opening
multiple sessions,... the speed of the first sessions doesn't drop. In
fact,.. each sessions has it's own 10% of the bandwith available.

Tests I've done:
- downloading from the XP machine on a locale machine (no or only one hop,
fast network)
This gives expected results like 70Mbit/s
- downloading from the XP machine on a distant machine (many hops, but still
fast network between it)
Gives poor results like 7Mbit/s
- downloading from the XP machine on another distant machine (also many
hops, still fast network between it)
Gives poor results like 7Mbit/s
- downloading from the XP machine on a distant machine opening multiple
sessions
Gives poor results like 7Mbit/s per session, but...
Gives expected results when opening 10 sessions (7Mbit/s per session, ... so
70Mbit/s all sessions)

After that I booted Linux on the SAME XP-machine and did the same tests:
- downloading from the Linux (old-XP) machine on a locale machine (no or
only one hop, fast network)
This gives expected results like 70Mbit/s
- downloading from the Linux (old-XP) machine on a distant machine (many
hops, but still fast network between it)
This gives expected results like 70Mbit/s
- downloading from the Linux (old-XP) machine on another distant machine
(also many hops, still fast network between it)
This gives expected results like 70Mbit/s
- downloading from the XP machine on a distant machine opening multiple
sessions
This gives expected results like 70Mbit/s on the first session
And equaly dividing the bandwith per session.

These results tell me it's NOT the network which is giving the problem.

Anyone ?

regards, Igor Ybema

 

[Guest]

20% limiting with the QoS scheduler is a hoax

You can disable it if you want Microsoft has a KB Article informing people of this.

 

[Igor Ybema]

20% limiting with the QoS scheduler is a hoax.

You can disable it if you want Microsoft has a KB Article informing people

of this.

I know... this is not the problem in my case.

regards, Igor