CAT5e home ethernet/network - transfer rates

[tcsenter]

I know the 'theoretical' throughput of a compliant CAT5e channel from TC to backplate is 100Mbps or 12.5 Megabytes/sec. But what 'real world' transfer rates could I reasonably expect if I were, say, transferring a 100MB file from one computer to another along the network? I realize it can vary, but if you installed a home network/ethernet with CAT5e, what real world transfer rates would you find satisfactory or even not satisfactory? TIA!

 

[cmetz]

100BaseTX - 100Mb/s (each way if FDX).
1000BaseT - 1000Mb/s (each way if FDX).
Other kinds of signalling, other data rates.

 

[skyking]

The cabling plant, if installed correctly, will not be the bottleneck. It will be NIC performance, HD access on smaller files, etc.

 

[tcsenter]

100BaseTX - 100Mb/s (each way if FDX).

Yeah, sorry about that, I didn't mention the ethernet standard, though I did imply it when I stated 100Mbps.

But that 100Mbps is simply the 'theoretical' maximum, like 100MBps is a theoretical maximum for ATA/100 HDD transfer rates.

What is a reasonable 'real world' transfer rate to expect?

 

[JackMDS]

100Mb/sec. (b-bit) suppose to yield a theoretical 12.5MB/sec. (B=Byte).

Small Home LAN using Entry Level Network Hardware.

In regular working windows envioroment, giving the variation of:

1. What else is running in the background?

2. What is the capacity of the Hard Drive and the computer general speed?

3. What application is used for the files transfer?

4. General over head of the network component

You get 5-8MB/sec.

Or 40 ? 65Mb/sec.

 

[cmetz]

With modern PCs and a modern operating system (NOT WINDOWS!) and TCP, exceeding 100Mb/s transfer rate isn't hard (well, obviously, you'll peak at high-90s on a 100Mb/s network).

What network application/protocol is in use has a huge impact; for example, Windows's SMB file sharing protocol is terrible for performance, but the same hardware and OS doing a ftp file transfer of large files can deliver pretty good performance. Without more of a description of what it is you want to know about the performance of, though, I don't think you're asking a specifically answerable question.

 

[tcsenter]

Ok, thanks for all the info. Sorry I wasn't more specific, I was presuming a high-end desktop; ~2.4GHz, 256~512MB RAM, 7200RPM HDD + ATA/100 subsystem, reasonably good 10/100 NIC, WinXP, etc.

The reason I am asking is that with Gigabit on the way as the de facto standard, I am wondering if CAT5e is going to be adequate in the years to come. House cable runs should be considered for all practical purposes at least semi-permanent, if not permanent.

IOW, will I in 10 years be wishing I had run CAT6 to begin with.

 

[cmetz]

This is why I tell people to run conduit wherever possible - to make it easy to pull through new cable later. The highest end stuff now will be low to lowest end ten years from now.

If you want to consider the cable permanent and are thinking in terms of ten years, good cat6 is probably worth it.

I don't understand how the IEEE folks are gonna get 10 gigabit over twisted-pair copper, and certainly it's way up in the air as to whether that'll end up being over cat5e, cat6, cat7, or who knows what. I was surprised to see them figure out how to get 1000BaseT working reliably over cat5e, but as you can see it's baked product now. What the future will hold, who knows? I will say that ten years ago, 100BaseTX was just starting to get LAN traction, and now it's pretty much the LAN default and 1000BaseT is just starting to get LAN traction. So my estimate is that a cable plant that supports 1000BaseT well today and has some headroom for the next thing is probably going to last you about a decade.

 

[dnoyeb]

of course 100Mb/s is not your throughput, the the hardware level throughput. Your files will not achieve that because of other protocols overhead.

 

[isaacmacdonald]

I think there's something beyond just protocol overhead and hardware limitations. There must be some X factor that reduces performance. Even on a crossover cable with 2 highperformance nics with proven thoroughput and full duplex opperation, I rarely get over 8MB/sec using tcp/ip with 100mbp/s ethernet. Based on the fact that it's running full duplex, there's got to be something else that factors in there.

 

[spidey07]

Based on the fact that it's running full duplex, there's got to be something else that factors in there

Its the hardware, protocol overhead and the millisecond acknowledgements going on.

100 Base-T can and will run upto 99.35 Mbits/sec when using the largest frames possible, 1514. As long as there are packets buffered for transmission you can fill up a 100 Base-T link. You only get 8-10 Megabytes a second when copying from one PC to another because that transmission buffer isn't always full either because of hardware, protocol or waiting for an acknowledgement from the receiver.

Hope that makes sense. If you want to help your LAN transferes set your TCP window to some insane amount like one megabyte.

 

[tcsenter]

IOW, will I in 10 years be wishing I had run CAT6 to begin with.

Holy crap. It just now occurred to me that CAT5e will easily do Gigabit. So if 100Mbps should become inadequate in 10 years, all I gotta do is buy some new NICs and Routers/Hubs, then I've got 1000Mbps. Woohoo!

 

[Night201]

Just ran a test for you. I transferred a 338MB file from my computer to another. Both computers are p3-866 with PC's with 7200RPM Maxtor 30GB drives. The NICS are linksys and they connect to a 16-port linksys router. There are about 10 other computers connected to this switch, so there may have been some overhead - I didn't look during the test, but hopefully this will give you a rough idea.

The 338MB file took 2 minutes and 30 seconds exactly to transfer = 2.5 megabytes/second.

 

[tcsenter]

Thanks for taking the time to do that and post your result.