Network speed woes...

[kerykeion]

Hello ... This a disappointing problem because I am trying to upgrade my current non-switched ethernet to a fast ethernet switched environment. Unfortunately, it seems as though I'm only getting roughly 1/10th of the speed that I should theoretically be seeing.

Here's how I have my simplified TCP/IP, peer-to-peer network:

Notebook using Linksys 10/100 PCMCIA NIC <-> 14ft. Cat5e straight-through cable <-> Linksys EZXS88W 10/100 switch <-> 14ft. Cat5e straight-through cable <-> Desktop computer using Netgear 10/100 PCI NIC

(All NICs using latest drivers)

Both NICs and the switch have the 100Mbit activity lights on ... even Win2000 on the notebook indicates 100Mbit. But when I used various files, Qcheck, and NetCPS to test the bandwidth of the network, everything was really running at ~9.5-10Mbits. In reality, I should be seeing around 70-80Mbit of throughput.

So what gives? My cables are fine, my NICs work, and there are no collisions. Is it a faulty switch?

 

[ScottMac]

What flavor and speed is the notebook?
What flavor and speed is the desktop?

What are the O/S on both?
Have you applied all of the updates to the OS?

Is the notebook NIC 16 bit or 32 (Cardbus?)

Notebooks, in general, run slower than their desktop counterparts...this is the compromise for portability and power conservation. Slower drives, slower busses, slower video, speed-throttled CPUs...that's the way the mop flops....

Did you make or buy/steal your cables? How do you know they're "good"? Poorly made cable routinely work OK at ten Meg, but just can't hual 100Meg.

The hub/switch would be the last place to look

Good Luck

Scott
.

 

[spidey07]

is the PCMCIA nic a cardbus adapter? If not then it is half-duplex and that could slow you down.

 

[kerykeion]

What flavor and speed is the notebook?
It's a Dell Inspiron 5000; Intel P3 @ 500 MHz

What flavor and speed is the desktop?
Gateway; Intel P2 @ 300 MHz

What are the O/S on both?
Win2K Pro SP2 on notebook, WinME on desktop

Have you applied all of the updates to the OS?
Yes

Is the notebook NIC 16 bit or 32 (Cardbus?)
It is 16-bit. I know this probably not going to hit 100Mbit, but I should see at least 20-30 Mbit.

Did you make or buy/steal your cables?
Bought ... they are identical 14 ft. Belkin Cat. 5e patch cables.

How do you know they're "good"?
They "seem" to be good ... no twists, tear, wear, or cuts ... and they are only about a year old.

 

[kerykeion]

...If not then it is half-duplex and that could slow you down.

Incidently, the "full-duplex" LED light on the switch is on for both ports that these computers are hooked to.

 

[spidey07]

there's your problem

the switch did not properly negotiate the speed/duplex with your 16-bit NIC. I may be wrong but I'm pretty sure 16-bit pcmcia NICs cannot do 100 Mbs/Full-duplex.

If the speed/duplex is not the same on both sides of the link you will get all kinds of errors and pitiful performance. See if you can manually set the speed/duplex on the switch.

 

[ScottMac]

Given the information, I'd guess it's probably a combination of a slow NIC in the notebook and the slower PC with a slow OS in the Desktop. Better NICs might help a little (something with a lot of onboard processing & good drivers), but probably not enough to justify the expense. A 32 Bit /Cardbus NIC in the laptop would probably be the single biggest boost.

You could try setting both computers to 100 Half duplex...it lets the computer "concentrate" on one thing at a time...getting stuff in, or getting stuff out. IF you go to half Duplex on the PCs, make sure the hub/switch sees the change and adapts.

Good Luck

Scott

 

[kerykeion]

I may be wrong but I'm pretty sure 16-bit pcmcia NICs cannot do 100 Mbs/Full-duplex.
Err.. I wish I had known that when I first bought it.. I guess their marketing scheme got me there.

If the speed/duplex is not the same on both sides of the link you will get all kinds of errors and pitiful performance. See if you can manually set the speed/duplex on the switch.
Fortunately, I haven't noticed any errors... just the slow performance. Unfortunately, I don't see any manual settings ... the switch is fully automatic/unmanaged.

You could try setting both computers to 100 Half duplex...it lets the computer "concentrate" on one thing at a time...getting stuff in, or getting stuff out. IF you go to half Duplex on the PCs, make sure the hub/switch sees the change and adapts.

Sure, I'll try that when I get the chance.

On another note, I had tried this same switch on another peer-peer network with Cat. 5 (not 5e) cabling. When I replaced the old 10Mbit 3Com hub with the switch, none of the computer NICs (mix of 10 and 10/100) could even establish a link with the switch at 10Mbit or at 100Mbit. The 3Com hub, on the other hand, continued to work fine...

 

[JackMDS]

Just as a frame of reference.

1. Desktop - Intel 1.8G Win98se, Netgear FA-311. 10/100TX
2. Desktop - AMD 450MHz Win98se, Netgear FA-311.10/100TX
3. Laptop AMD 330MHz, Win98se, No name 16 bit PCMCIA.

All three connected to TX Switch using 6' CAT5e commercial made.

Firewalls disabled, Screensavers Disabled.

Using Qcheck. TCP Throughput.

Desktop to Desktop 62 Mb/sec.

Desktop to laptop 12Mb/sec.

Desktop to Desktop (while second Desktop running slide show Screen saver), 22Mb/sec.

These computers are purposely one next to the other for Network evals. Testing was done in the passing hour.

 

[kerykeion]

Thanks for the reference figures ... I brought this issue because my network seems suspiciously capped at 10Mbit/sec -- no more, no less -- I can't see why I can't get above it.

About the 16-bit limitations...
Quote from Tom's Hardware Guide; "Although 16-bit PC-Cards claim 100 megabit performance, in our opinion it would be better stated that, while the card is able to connect at 100 megabit, your real performance is limited to about 20 to 25 megabit because of the limitations of the 16-bit PC-Card bus."

Secondly, looking at the TCP Throughput of various notebook NICs, the slowest is around 16Mb. Technically, mine should be closest to the Linksys PCMLM56 which benchs at ~21Mb.

Posted by ScottMac: Given the information, I'd guess it's probably a combination of a slow NIC in the notebook and the slower PC with a slow OS in the Desktop...

How much slower is WinME than Win2K when it comes to network performance? Can WinME be tweaked ... perhaps by changing the TCP Receive Window in the registry?

 

[ScottMac]

Check out the tweaks from DSLreports. They have an app called Dr.TCP that lets you change windows & other parms on-the-fly. Some folks report problems with Dr.TCP, I've used it with no problem. THe same area has some registry overlay patches that seemed to help my system (one with WinME).

Check it out, don't do any regestry stuff without backing it up first. Also write down all the parms before you change 'em, just in case something gets FUBAR along the way.

Good Luck

Scott