slow data transfer via 100mbps network

[DrZone]

I have a Dlink Di704 router and three machines on it. All the machines have 100mbps cards in them and are enabled at 100mbps.

The internet works quite well on all machines and they all get the peak speeds.

However, data transfer between machines is reeeaally slow. There have been the odd times where the data transfers fine. But most of the time it's reeally slow.

Any ideas ?? Thanks in advance !

 

[Paulson]

Are the computers really slow or have slower hard drives?

(This probably isn't the problem, but you didn't mention what kind of machines you had)

 

[kazeakuma]

Are the nics running at half or full duplex? If they're running at half duplex they'll take a big hit. And I'm not familiar with the dlink you have so I'll ask, Hub or Switch?

 

[DrZone]

Both PCs have pretty new hard drives in them. The NICs are at 100mbps Full-Duplex.

And the Dlink is a 4 port switch

 

[kazeakuma]

hmmm.
Are the nics identical? Drivers updated? I've had similar problems one larger networks were one or two pcs will transfer at speeds well below 10mbps despite being 100mpbs and full duplex.

 

[DrZone]

Yes all the drivers are up-to-date. Funny thing is, the speeds are sometimes VERY good.

For example, i just reset the router and it seems to have improved.

Also, is there a possibility that having a program like icq open will degrade the speeds across the network during transfer ?

 

[splice]

What do you mean by really slow? Have you done any bandwidth measurements? Max bandwidth avail is 12.5MBytes/s. On my 100Mbps lan I get around 7 - 10MB/s

 

[gramb0]

The traffic could be getting routed through internet. How are you transfering the files? I know with FTP (using external IPs), between certain machines on my lan, the traffic gets routed out through internet dropping it to 60kbyte/s even though all the machines are on a switch. The weird thing is, it only happens on one machine.

 

[DrZone]

I dont think I'm having any of the problems listed above. It maybe due to the receive buffer. I have the "receive buffer" option in winXP but not in win2k. Is there such a feature in win2k ?

 

[DrZone]

Oh and one more thing. Between two machines, the file transfer when sending from PC1 to PC2 are fine and quite fast. But from PC2 to PC1 it's really slow.

 

[RanDum72]

what brand NICs do you use?. Also check your cables. Sometimes setting the NIC's to Auto (instead of specifying 100mbs full-duplex) under the NIC properties will allow the card to sync properly with the switch.

 

[DrZone]

<< what brand NICs do you use?. Also check your cables. Sometimes setting the NIC's to Auto (instead of specifying 100mbs full-duplex) under the NIC properties will allow the card to sync properly with the switch. >>



Both cards are Dlink NICs. If i set the NIC's the auto, that may cause them to go at 10mbps sometimes wont it ? I want to make sure that they're constantly at 100mbps

 

[RanDum72]

The DI-704 (which I used to have) supports auto-negotiation and so does the DLink NICs (I believe you have the 530tx+?). You can look at the status lights in your router and see if they change or not (which they shouldn't) unless you specify 10mbs operation.

 

[JohnnyPC]

Check and see if the activity light is constantly on during one of these slow periods. Could be a chatty (defective) NIC sending out misc packets causing broadcast storm collisions on the LAN...if so replace that NIC and the issue should be resolved...

 

[DrZone]

<< Check and see if the activity light is constantly on during one of these slow periods. Could be a chatty (defective) NIC sending out misc packets causing broadcast storm collisions on the LAN...if so replace that NIC and the issue should be resolved... >>



I actually ping the router frequently from both machines. And i dont get any packet loss.

I recently changed both NICs to auto negotiate and it seems to have improved the speeds. I'll have to monitor this for the next few days to see if that has entirely resolved the problem.

 

[zephyrprime]

I had a similiar problem with my win98, win2K network. I asked the people here on anand and they had no idea. I was getting around 40mbps so I don't think my problem was as severe as yours. I also experienced the strange problem of the speeds from computer1->computer2 being different than from computer2->computer1. I tried all sorts of things. I tried buying a new network card. I tried a crossover cable, different cables, etc. Nothing helped. I finally read an old article in PC Magazine that said that the networking on NT 3.11 was just inproperly implemented and that microsoft was hoping to fix this problem in NT 5 (which is NT 2K). I figured that 98 must just have been coded crappy and there was nothing I could do about it. I'm not sure if this is your problem though.

 

[DrZone]

<< I had a similiar problem with my win98, win2K network. I asked the people here on anand and they had no idea. I was getting around 40mbps so I don't think my problem was as severe as yours. I also experienced the strange problem of the speeds from computer1->computer2 being different than from computer2->computer1. I tried all sorts of things. I tried buying a new network card. I tried a crossover cable, different cables, etc. Nothing helped. I finally read an old article in PC Magazine that said that the networking on NT 3.11 was just inproperly implemented and that microsoft was hoping to fix this problem in NT 5 (which is NT 2K). I figured that 98 must just have been coded crappy and there was nothing I could do about it. I'm not sure if this is your problem though. >>



Well, I'm still running the NICs on auto negotiate now and they're fine so far. Speeds are consistent between both machines. So i think maybe the cards werent sync'ing properly with my router when they were set to 100mbps.

 

[Ben]

What OS are your boxes running?

I've had this problem with several LAN's. It's almost always associated with WinME and/or Win98.

I haven't found an official fix other than to upgrade the OS's to something using the NT kernel.

 

[Maverick]

check the cables. Bad cables will drop your speeds quite a bit. We had a snap server at work that was transfering at 2.5K/sec over a 100 mbps network because of a bad cable to the switch.

 

[SocrPlyr]

i have had the problem that when going from one machine to another was fast, but the other way around wasn't... i found out that it was b/c i was trying to upload to the other computer instead of going to that other computer and downloading... i don't have an explaination for this but that is what happened to me... maybe it has something to do w/ windows...

Josh