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Home » Forums » Forum Archives » Networking and Internet Sharing » Topic # 1743

Slow LAN
jardo Mar-03-02 10:21 PM
I've got a home LAN connected through a switched Linksys 4-port router. My problem is that I've got all NIC's setup to run at 100/full, the Router shows that all clients are running at 100/full, but my transfer speeds are more like 10/half.

I have even tried to bypass the router with a cross-over cable. Again, the computers connect just fine, but my transfer rate is 1meg per 1.3 seconds on the average. It takes 15-20 minutes to move a 650meg file. This can't be right!!

The cables are good, I know that. The router does not indicate collisions. The only thing I can figure are windows network registry settings (MTU and the like), but I don't know anything about that stuff.

Does anyone have any ideas?


1. RE: Slow LAN
lbyard Mar-04-02 12:51 PM
In response to message 0
>my transfer speeds are more like 10/half. 1meg per 1.3 seconds on the average…

Or about 100 Mbytes in about 2 minutes, 10 seconds. That is not like 10/half. It is slow for 100/full, which will transfer 100 Mbytes in about 1 minute 20 seconds or somewhat less.

>The cables are good, I know that.

How do you know that? How long are they?

>The only thing I can figure are windows network registry settings (MTU and the like).

Very unlikely.

Larry


2. RE: Slow LAN
jardo Mar-06-02 00:41 AM
In response to message 1
Well, I was being a bit sarcastic with the 10/half comparison, but it does seem slow to me. Thanks for the perspective. So you are saying that I am really getting 'close' to 100/full speeds? From what you say, I am still getting only half the speed I should. So, maybe the proper analogy would have been that I am getting more like 100/half speeds.

I get the same transfer rate between all my systems. When I did testing between two pc's going around the router with a cross-over, the cable was only 5' long. Still same performance in that test as when I go through the router.

If it isn't network registry settings, the only other thing I can think of is the fact that I use an assortment of NIC's. (USB Linksys, PCI Intel, PCI Netgear, and PCMCIA Linksys).


3. RE: Slow LAN
lbyard Mar-06-02 11:29 AM
In response to message 2
As I said, I doubt very strongly that the problem has anything to do with registry settings (unless you have played with them). I do not think it is because you have a mixture of network adapters, but that is not as low probability as registry settings. To put these statements in context, I have networked hundreds, maybe thousands, of PCs over the lat 15 years. I believe I have seen one registry problem and perhaps a handful of mixed NIC problems. If those cables are homemade, they are the most likely cause (http://duxcw.com/faq/network/cableprob.htm). Check the ends of the cables and make sure they are made properly (http://duxcw.com/digest/Howto/network/cable/cable7.htm). Also, if you have not used the correct wire and plugs, you may see the problems you describe, if they work at all. Many people have a conceptual problem in understanding this. We are not dealing with Christmas tree lights, a car battery, or telephone wiring (http://duxcw.com/digest/Howto/network/cable/cable4.htm). Larry

4. RE: Slow LAN
jardo Mar-09-02 04:07 PM
In response to message 3
Well, I read the suggested ethernet cable faq's. Nothing was new or unknown to me. I went ahead and verified all my cable ends. They are all straight-through cables conforming to the EIA/TIA 568B spec. My next step is to purchase a cross-over cable and see if I can find two of my PC's that perform as I would think that a 100/full should. Then I will use these two machines to test the rest of my cables.

I did further testing with DU Meter. My network is maxing-out at 10.8mbits per second. That is faster than a 10mbit connection would ever theoretically go, but still far below where a 100mbit connection should be. My goal on a 100mbit/full network is ~70mbit per second.


5. RE: Slow LAN
jardo Mar-11-02 09:52 AM
In response to message 3
Update,

I bought a professionally manufactured, sheilded, 7ft cross-over cable and did some file transfer tests directly between workstations. (removing both my router and switch from the equation). I still can not acheive greater than 5.0mbit on average. Using DU Meter scaled for a 100mbit LAN connection you can't even see the graph data!! I hate to blow your easy answer but I don't know what more I can do with the cables. Something other than cableing is wrong here.


6. RE: Slow LAN
lbyard Mar-11-02 05:16 PM
In response to message 5
>I hate to blow your easy answer…

You didn’t. It may not solve the problem you are having, but it was the likely and correct answer to your first post.

>…professionally manufactured, sheilded, 7ft cross-over cable.

I don’t know why you would buy shielded cable unless that is what is commonly used where you are located. Does “professionally manufactured” mean a name brand cable, or was it made locally by a “professional”? If it was made locally, how fast was it when they tested it. Professionally made cables are tested cables, tested at Ethernet speeds.

>I still can not acheive greater than 5.0mbit.

Your benchmark numbers keep changing. Perhaps the crossover cable is worse? It looks like it.

>My goal on a 100mbit/full network is ~70mbit per second.

That’s nice. How fast can your hard disk drive copy files to itself? Try copying about 100 Mbytes of files from one folder to another (I use the Windows 98 Upgrade cab files: D:\>win98\*.* without the subdirectories). Do you think your computer can copy the same files from the hard disk to another one via your network faster, or will it be slower than the slowest drive/computer? Larry


7. RE: Slow LAN
jardo Mar-13-02 01:11 AM
In response to message 6
>I don’t know why you would buy shielded cable unless that is
>what is commonly used where you are located. Does
>“professionally manufactured” mean a name brand cable, or
>was it made locally by a “professional”? If it was made
>locally, how fast was it when they tested it.
>Professionally made cables are tested cables, tested at
>Ethernet speeds.

I bought sheilded only because I did not want that to be an issue. It was a packaged cable from Fry's. Not made locally as far as I know. Whether tested at Ethernet speeds, I don't know. But at 7 feet, I would imagine that this should not be a problem unless the cable were damaged. At this point, I have tried so many cables, some purchased and others made by me, I would think that one of them would be alright.

>>I still can not acheive greater than 5.0mbit.
>
>Your benchmark numbers keep changing. Perhaps the crossover
>cable is worse? It looks like it.

Yes, the numbers did change because I was confused at first between Mbits and Mbytes. I now know for sure that these are Mbit measurements and on a 100Mbit network my speeds are slow.

>That’s nice. How fast can your hard disk drive copy files
>to itself?

Hmmm. Good point. I'll have to look at this, but am pretty sure that I can move data between my hard-drives at speeds that far exceed the capability of my network. I would expect that even if my network worked as expected that it would still be the bottle-neck to the speed of the hard-drives. But I will have to check.

So I have two action items here. I'm going to try to time my HD throughput. Also, I plan on taking my laptop to work and see if it behaves differently on the network there.


8. RE: Slow LAN
lbyard Mar-13-02 12:57 PM
In response to message 7
>I would expect that even if my network worked as expected that it would still be the bottle-neck to the speed of the hard-drives.

10BASE-T: yes. 100BASE-TX (working correctly with most PC/notebook drives): no. Also, allow a generous PC overhead (say about 25%) for transferrring through the bus, processing the info on the hard disk into packets, etc. and back again, and processing by the NIC. Latency also figures into the equation. Larry


9. RE: Slow LAN
jardo Mar-18-02 09:17 PM
In response to message 8
Bottom line. Taking HD speed and PC overhead into account, I think we can both agree that with 100BASE-TX network I should be getting greater than 5mbit speeds. But, in your estimation, what is the max I should look for? 50mbit? 60mbit? 70mbit?

10. RE: Slow LAN
DJ Net2Infinity Mar-18-02 09:44 PM
In response to message 9
Are you using NetBIOS or TCP/IP or both?

12. RE: Slow LAN
jardo Mar-20-02 01:18 PM
In response to message 10
I used to use NETBIOS before I added a WinXP system to my network. I've since removed NETBIOS from all systems on my network and use TCP/IP for file sharing now.

11. RE: Slow LAN
lbyard Mar-19-02 02:56 PM
In response to message 9
I'm getting about four times that, but I am using my homegrown benchmark, transferring the Windows 98SE cab files (about 105 MBytes between two computers. Using a 500 MHz K6-2 with Windows Me, 256 Mbytes, and a 7,200 RPM ATA/100 drive and transferring with a crossover cable to a 333 MHz K6-2 with Windows 2000 Pro, 64 Mbytes, and a 5,400 RPM ATA/66 drive it takes about 45 seconds (105X8/45=19 bps of actual data at the application level transferred). Previous benchmarks were done with slower computers/disk drives and it took over a minute. What do you get with my benchmark? Larry

13. RE: Slow LAN
jardo Mar-20-02 01:27 PM
In response to message 11
I'm going between a WinXP machine with a 5400rpm drive on a ATA/66 controller to a Win2K machine with a 5400rpm drive on a ATA/66 controller. My network is configured for 100mbit Full Duplex.

Transfering 3 33meg files from one to the other takes approximatly 3 minutes. (99*8/180=4.4 bps right?)


14. RE: Slow LAN
lbyard Mar-20-02 02:29 PM
In response to message 13
Right. And that's 2-3 times slower than it should be and roughly the speed I would expect from 10BASET (http://duxcw.com/digest/Reviews/Network/dlink/dhn910/dhn910-4.htm). Do the adapters have 10/100 LEDs? Larry

15. RE: Slow LAN
timw88 Mar-20-02 06:03 PM
In response to message 14
Please try this. I know that lbyard is probably right in that it is not a registry problem but the fact is that nowadays due to net acceleration programs, etc... the maximum value of the DefaultRcvWindow in the registry can severly limit bandwidth. Some software programs and/or ISP software adjusts the default values to try to maximize dial-up performance.

This is probably not going to solve your problem since even though your speeds are slower than you expect, they are still much faster than a dial up.

All you have to do is download the patch from http://cable-dsl.home.att.net/#IncreasingWindow to both PC's (applicable for Win 2000 and XP) and it will adjust your GlobalMaxTcpWindowSize to normal. Be sure to download the patch for Win 2000 and XP. This will take you less than 2 minutes and will not harm your machine.

I have seen this patch (and the manual adjustment of TCP Receive Values in the registry) solve speed issues on hundreds of DSL and cable modem installations. You are dealing with an internal LAN and not a WAN connection but the same applies.

Good luck,

Tim


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