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-   -   upgrading from 10mbps HD to 100mbps FD, transfer speeds at an all time low (

Sir Dwain 10-02-2004 12:32 PM

upgrading from 10mbps HD to 100mbps FD, transfer speeds at an all time low
In our house we have a setup with a gateway-pc running debian sharing internet and acting as ftp-server for the rest of us (all in all 7 computers with various OS's: win xp pro, slackware 10 and debian 3.0r1 & 3.0r2). This used to be a stable and working setup, until we decided to get rid of our 2 hubs in favour for a switch (thinking that running at 100baseTx-FD should be faster than 10baseT-HD). Immideatly after putting the switch to use all seemed to be well (the entire network still operating at 10mpbs) but when trying to upgrade the speed things started to go wrong. Having spent some more money getting a new nic (3c95x)for the gateway (replacing one of those realtek 8139 ones) all seemed to be able to make the setting 100mbps full duplex and everything should be fine right?
However, when downloading from the ftp-server i am getting speeds like 20KB/s, compared to roughly 950KB/s before the "upgrade" so something is definetly not right, but what?

Running mii-tool -v on the gateway shows that both nic's (the one connected to the cable modem and the one connected to the switch) have successfully autonegotiated 100baseTx-FD. Transfer speeds are as far as I can tell much worse than before for everybody and every computer (except for the occasional "no link" problem) have been able to set its nic to 100mpbs full duplex.

Any ideas or any other info you'd like?

symen 10-04-2004 01:33 AM

What happens when your clients communicate with each other? is this just as slow or is it only when communicating with the ftp server?

Sir Dwain 10-04-2004 02:23 AM

It seems to vary greatly, but usually samba communication between clients other than the server is extremely slow. This might've been a shorewall issue (I tried force opening of the smb ports but haven't yet been able to see if there's any improvement). What however really confuses me is that transferspeeds to an xbox ftp-server included in the network are fine (at roughly 6000KB/s), this is especially puzzling considering whenever a successfull connection to the xbox have been made access to the rest of the network is no more (until after a couple of restarts)

It seems this whole setup is a mess, could it be that our switch is malfunctioning? it is a brand new "Level One" 8ports 10/100mbps.

Using 10mbps half duplex settings will improve transferspeeds to and from the major ftp-server (only with ftp, connection to its samba server is unacceptably slow (which is the reason I had to setup a ftp-server for local use in the first place))

I'm all out of ideas and people here count on me to solve their problems, what to do?

symen 10-04-2004 03:10 AM

Is your switch configurable? Have you tried updating its firmware?
After you have used the x-box, can your clients still use network (even surf the web)?
What about the win users among each other? how are they communicating?
Can you see collisions on your switch? what kind of network cable are you using (cat 5?)? How long are the cables? Do you use UTP or STP cables.
what happens if you connect a client straight to the server without switch (use crossover cable)?

Cabling is becomes a lot more important when moving to 100Base. You could be suffering signal distortion.

Sir Dwain 10-04-2004 04:52 PM

The switch is not configurable to my knowledge (nor do I find anything about such matters in the manual) and there's no new firmware available. Nevermind about the xbox issue, it works now, I don't know why, I don't think anything important has been changed.
Windows users I believe communicate fine amongst each other, with one exception, and are as far as I know able to share files and browse the network and whatnot with acceptable speed, however they too have problems accessing the gateways samba-server and they are getting bad transfer rates from its ftp-server (bad in this case meaning roughly 1000KB/s, which still is about a 1000 times faster than I get, running either slackware 10 or win xp.) So it would appear that something is wrong with my computer (especially since I get the same problems with 2 different OS's, right?) so I have tried replacing my nic, with no effect, and tried different network cables (i don't know what they are called exactly, is there any way to tell by the way they look?) network cables that have been working for others mind you.

Collisions... i don't know about that one, but the point of a switch is to avoid collisions?
I will try connecting with a crossover cable but I do not have one long enough to try at the moment.
I don't think the length of our cables should be the problem, with 7 computers there's probably about 60 metres of them all together.

It seems the entire network is completely random, sometimes (mostly now) internet sharing and basic low-speed network access works, but everytime a computer is turned on or off there's a risk of everything going down. Now, I would expect this sort of behaviour with a windows-only network, but I am not satisfied with this performance when it comes to linux2linux connections.

One idea that I did have was that shorewall might be blocking smb and/or ftp ports, but that was proven wrong since turning shorewall off would not improve transfers.

Sir Dwain 10-05-2004 06:48 PM

ah, I'm an idiot. I completely forgot to check up on something of great importance.

The thing is, download speed from the gateway/ftp-server at 100base is about 20kb/s and at 10base it is about 800kb/s
However, uploads, at 100base, are roughly 50kb/s and at 10base somewhere around 650kb/s

What I previously missed was that I was comparing download speeds from the gateway with upload speeds to the xbox.

Uploading to xbox-ftp at 100base works flawlessly at about 6000kb/s, however downloads speeds are just as pathetic as with the gateway
Uploading at 10base will give me roughly 1000kb/s whilst downloads are no faster (or much slower) than 850kb/s.
So clearly there's an issue with ... what ? ... I am sure it is very obvious to some of you guys now.
at least I hope so

(and I have tried switching network cards a few times)

edit: Oh and the same problem applies to external downloads, slow at 100mbps (although working, which is an improvement) and a great deal faster at 10mbps.

symen 10-06-2004 06:50 AM

I would really try to compare the speeds after bypassing the switch.
What you should get is one or two megabytes a second. not more.
Your theoretical network speed is ten megabytes a second (100base), but your drives and system won't be able to handle anything near it. Certainly if you are transferring smaller files.

RandomLinuxNewb 10-06-2004 11:01 AM

Your best test right now is to find a crossover cable and plug right in to the gateway. Then transfer something big, 600 MB would be good. This will test to see if it's a switch issue or some card issue.

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