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Problem with LAN speed

Posted on 2008-10-14
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Last Modified: 2008-10-15
Hello Experts,
Small office, 6 computers and 1 ProLian G3 SBS 2003 server expirencing slow network.
Router is Linksys WRS4400N Gigabit security and they have Linksys 16 port 10/100/1K SR2016 switch. All connectet with Cat 5 RJ45.
Server and two workstations have 1G network card, other workstations have 10/100 network cards. All workstations have Windows XP pro.
680MB of data transferred  from server to 10/100 workstation takes 20 min and network utilization is all over, from 1% up to 26%. Jumps up and down, but I would say average would be around 12% to 15%. CPU usage from 3% to 10% on work station and 1% to 5% on the server.  Transferring 680MB of data from one hard drive to second hard drive on server took about 30 sec, maybe little less.
Transferring  4.5G from server to 1K workstation took about 4min. Network utilization was from 2% to 5%.
I believe all that should be a lot faster. I believe that 680MB should not take longer the 2  4 min and 4.5G should be done in less than min.
I have use wireshark to capture network traffic, but do not understand much. I would be happy to send someone a log if possible. It is 10MB so I can not attache it.
Please help me understand what is going on and what I should look for to fix it. Computers have antivirus programs. One computer is in other building and they pool cable underground and I believe it is at least 150 if not longer. They notice slow response using Business Vision week ago and before was ok.
Any suggestion will be greatly appreciated.
Thank you :)
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Question by:grujiczoran
12 Comments
 
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Expert Comment

by:RSLE
ID: 22720856
look for ethernet duplex mismatches.
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by:grujiczoran
ID: 22721026
Hello,
All network cards are set to Auto. Linksys switch is nonmanaged and should be smart. For router I do not know where to look for.
Computers look clean from viruses. Internet speed is very good. LAN is slow.
Thank you for help. :)
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Expert Comment

by:Trilog-Studios
ID: 22721477
hi..

was the 680mb package or the 4.5gb package a single file or many small files?? then is it also slow wen coping the same amount from one workstation to another?
if you try the workstation-to-workstation please also captur the network with wireshark.

if both ways are equally slow then there should be a problem with your network( interference of some kind or so) also the rule applies: the networkis as fast as its slowest component. perhaps a netwokcard is ''giving up'' or there could be a cable break somewere.
( also try clearing the cach/connection history of your server.)
TS
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Expert Comment

by:RSLE
ID: 22721881
Still, don't always rely on auto negotiation being correct... I've had numerous cases where it doesn't always work as it should (Nortel & Alvarion gear immediately come to mind for me).  Verify the port speed & duplex on the computer's NIC's.  You're out of luck with the switch though and have to assume they got it right since Linksys doesn't give any duplex indicators on their unmanaged business switches (odd since they DO put them on their home user EZ series switches).  As TS mentioned... try a computer to computer test (will require an ethernet crossover cable or auto-MDIX on one of the PC's).
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by:grujiczoran
ID: 22722014
Hello,
680MB package was many smaller files. I did not check individually file size, but I would say that they ranged from few kb to 100-150mb. 4.5G package was as well many files and they are all jpg, php and some bmp. Some are 800Mb in size. I tryed to transfer 680Mb from server to other workstation and it was slower then first one (second workstation is faster and better machine)
first time when I transfer 680MB from serwer to workstation only server and workstation was on. Second times all workstations was on.
Wireshark is not much of use to me as I realy do not know how to analize it. It is 10Mb in size, so I can not attach it for someone to help me with it. I do not know if there is other way to post it so you guys can help me.
Thank you so much for fast response. :)
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Author Comment

by:grujiczoran
ID: 22722459
Hello,
All network cards are set to auto negotiation, I could set it to 100 full duplex. Would that be better? Since two workstation have 1G network cards, should I set them to 1000 full duplex? Also is there posible that switch or router are week thouth Internet working great?
Thank you. :)
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RSLE earned 450 total points
ID: 22722870
It's certainly worth trying... as for the gig cards, I'd run with the full gig just in case the switch only detects the connection as gig... but at least there are LED's for 100/1000 speed on your switch so you should be able to verify this.

It's always possible for an inline device to be the culprit... I'm guessing your internet connection is not 1Gb/s or even 100Mb/s so it's not hard to imagine a case where a small internet load is handled fine but a much larger intranet load is hindered.  As TS mentioned it's also possible a NIC is the culprit.  I'd start with the switch... and if possible do the direct connect PC to Server test.
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Author Comment

by:grujiczoran
ID: 22723064
Hello,
I'm going to change a switch. I'm going there right now. Soon as I got back I will post feedback. Please do not give up on me. It could take me a 2 to 3 hours to get there and back.
Thank you. :)
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Author Comment

by:grujiczoran
ID: 22723955
Hello,
I changed Linksys switch with D-Link and I could transfer 680MB from server to workstation under 3 min. I could not mesure seconds, but I would say it was more like 2 min 45 sec only less. So that would be about 33 megabit per second. Is taht good speed or should be faster? Thought, it is fantastic impruve from 20 min before. I also testet same 680MB on other workstation and resolt was same. That second workstation was took longer almost 30 min before.
Thank you. :)
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Assisted Solution

by:rickhobbs
rickhobbs earned 50 total points
ID: 22725554
33MB/s is very good for a 100Mb connection including overhead (file creation, etc)
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Assisted Solution

by:RSLE
RSLE earned 450 total points
ID: 22725658
much better!  Yeah 33 Mb/s does still sound slow for a 100Mb LAN, but then you have to consider a few things...
1)  windows file sharing is not very efficient.  If you want a better test use ftp or a tool like iperf (http://dast.nlanr.net/projects/Iperf/) or qcheck (http://www.ixiacom.com/products/performance_applications/pa_display.php?skey=qcheck).
2) it's a shared LAN
3) TCP involves checking the received data and resending it if it's corrupted or dropped whereas UDP doesn't... so to really see throughput test using UDP w/ iperf or qcheck...
4) different cards, drivers and PC's will perform differently.

On a 100Mb direct connection between 2 computers using ftp to test, I'd hope to see around 80 to 90Mb/s.  Using a gig direct connect on my laptop I usually only see about 600Mb/s when using ftp but then I know one of my colleagues sees better.
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Author Comment

by:grujiczoran
ID: 22727124
Hello everybody,
I would like to make point that Im not a Guru on this subject. I just notice it in author lines. I did it by mistake. It was not intentional.
Im apologizing for it.
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