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Can "Enhanced G" really reach 125Mbps?

"P.Schuman" hath wroth:

It's about 1/2 maximum assuming that *ALL* users and systems heard are using Afterburner, Super-G, Turbo-G, or whatever. If there are any packets flying around that do NOT use the "Enhanced G" (never heard of that one) protocol, it will slow down. The worst is if you have the

802.11b compatibility mode enabled. Pre-802.11n Draft 2 doesn't even allow 802.11b compatibility. If you want the advertised thruput, you have to run it in 802.11n ONLY mode, with all the bandwidth hogging channel bonding features enabled.

Also, add a little interference, multipath, and other users on the channel, and you'll never even get close to 1/2 the connect speed.

See:

The reduction due to 802.11b compatibility is worst case and does not reflect current technology. My guess(tm) is that Max TCP thruput is about 15-25Mbits/sec with 802.11b compatibility enabled.

I use IPerf for testing.

If you search this newsgroup for past posting mentioning IPerf, you'll find some numbers.

No kidding. I'm shopping for an NAS box for a customer and am finding big variations in performance.

They use IOzone for testing:

For Windoze, IOzone runs under Cygwin.

Reply to
Jeff Liebermann
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On Fri, 18 Jan 2008 10:33:20 -0600, "P.Schuman" wrote in :

Not unless the PC is ancient -- even my old Pentium Pro server is more than fast enough to max out a wireless LAN or 100 Mbps Ethernet.

Reply to
John Navas

On Fri, 18 Jan 2008 11:53:38 -0500, ohaya wrote in :

Correct. You do in fact have a 54 Mbps connection.

Reply to
John Navas

the other thing we found - several years ago - was the impact of running the Virus Scanner duirng the backup or file copying. Depending upon the backup software, if it was just a file by file technology, then each file was going thru the virus scanner at each end.... Also had Task Manager running to see how the CPU was used... max'd vs idling

Reply to
P.Schuman

ohaya hath wroth:

That's what you'll get with 54Mbits/sec connection speed. You're not getting a 125Mbit/sec connection.

At what distance were you testing? 54Mbits/sec craps out at about 15 meters range (using the stock antennas and a typical laptop client). Using my rule-of-thumb, you get half the range for 4 times the connection speed. So, 125Mbit/sec should crap out at about 11 meters range.

One thing to watch for is that the connection speed indicated by the wireless clients status monitor will show variations in connection speed. The usual algorithm is to go as fast as you can when there's no traffic (duh!), and then slow down when there's traffic to deal with the errors. To the casual observer, it may look like you're getting a 54Mbit/sec (or faster) connection, but unless you monitor the traffic with a sniffer, or that the status page is fairly fast on updating the speeds, you'll never see the reduction in connection speed.

Reply to
Jeff Liebermann

Jeff,

I think that the distance is about 15 feet.

I saw your earlier post in this thread, where you mentioned that it may be worst with 802.11b compatibility enabled, which it is (what the router setup calls "b+g"). I'll try to iperf tests again with the router set to "g" only.

Thanks, Jim

Reply to
ohaya

ohaya hath wroth:

I did some testing in the past. See:

for numbers. The results were weird. I actually got better preformance with the 802.11b compatibility mode enabled, than with it off. No clue why. I should probably retest with current hardware and firmware (yet another project).

Reply to
Jeff Liebermann

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