10-15Mbps on 100baseT??? Why?

[Sojourner]

I have 3 coputers, each with 10/100 nics on a linksys 10/100 hub and can get no faster than 15Mbps xfers. Is this normal? All hub inputs show 100baseT and all the cables are definatly Cat5. The speed is the same from no matter which 2 machines I use.

[MosDef112]

Your hub probably does not feature Auto Negotiation or Auto Sense, in which case you must force 100MB line rate on your NIC's. You can do this by manipulating the software on your workstation. Go to your Network control panel, then to your NIC's properties, select the Speed option, and change it from Autosense to 100.

[Sojourner]

I did that! The hub detected and displays a indication the 100baseT connection is running. I have used different machines and different cables. I guess the only thing I havn't tried is a crossover cable.

[MosDef112]

Crossover cabling is only to be used when connecting hubs together that do not have a dual function port, or when connecting 100MB 10Base switches together, or, if you're too cheap to get a hub, when connecting two NIC's together. :) Are you running multiple protocols? Like IPX? I've seen IPX cut frames per second rate on 100 10Base switches considerably, particularly on a large LAN. Cut down on protocols, that might do the trick.

[Matt615]

Well I have a two computer network connected directly by a crossover cable. From one of the computers to the other it goes about 10-15Mbps, when I go the other way it usually goes about 20-30Mbps. I have both cards set at 100 Full Duplex and this is the fastest transfers I get. I can get bursts of up to 40 sometimes but going the other way I really only get burst of 20.

[MosDef112]

Then it must be that you have two different NIC's on your PC's. Unless you're using the Intel Pro/100 or the 3Com 3C905CTX NIC, expect not to achieve spectacular performance.

[Sojourner]

That must be the only explanation. I am running TCP/IP only and do have 2 cheap nic's out of the three. Why should I not expect a 20 dollar 100baseT card to work at least near 100baseT? Is that false advertising? Is any thing over 10Mbps considered a "100baseT" card?

[MosDef112]

All peripheral manufacturers will tell you their products meet certain standards or will support certain technologies. How credible this is relies upon us, the beta testers and ultimately, the customers. You will certainly see a performance improvement when buying a $80 NIC as opposed to a $20 NIC. It all depends on what kinds of architecture are being used on the hardware.

[Matt615]

OK yeah it makes sense, I have two different Nic's and one was like $20 and the other I dont know.

[MosDef112]

There ya go.

[TheRiov]

Remember that a 100BaseT Hub is 100 Mb/S across the whole hub. Thus a 10 port Hub only gets 10 Mb/S on each port, and an eight port Hub is ~12 Mb/S on each port. If you want 100 Mb/S on each port you need a Switch or Router.

[lundrog]

Check all your cables with a cable tester.
Get good networking cards.
Read reviews or just get a 3com.
Make sure your hub supports the speed.
Try a router and see if the speed changes.

[AMPLIFRIER]

i run all netgear fa311 nics and i get full 100mbps over my network.

but beware they cause a problem with restarting on FIC and Gigabye mobo's (both were AMD)
had to use a diff nic
it was a compliancy issue
dont remember exactly

other than that mine have worked great and liek 20 bucks each

if i get anything else itll prolly be the intel pro card

AMP

[jorey]

Sorry for this additional newbie question in this thread. How do u
guys measure these data speeds on the network? Reason for my question being a.o. a hub always works half duplex (inherent with
the CSMA/CD function) and the bandwidth is shared among the users. Second, your application also has some influence in speed. Most applications (to my limited experience) push a lot of 64byte packets on the wire which leads to an ineffective use of bandwidth.
Some tools I have been using were 'wsttcp' and 'Qcheck'.
Kind Rgds
J.R.

[MosDef112]

Yup.. You'll get full duplex with a switch, that is if you're using a 100MBit full duplex capable NIC.

[PhyberOptix]

Hey Jorey

1/2 duplex won't affect dl speed if only one pc is using the hub at that time.

Most TCP apps don't use 64 byte packets except for TCP administrative purposes (SYN, FIN, and ACKs).
UDP apps will use smaller packets if their traffic is interactive or real time - like voice, video, or video games.