I have problem with the Pre-N router and PC-Card. When using 2 connected computers, I don't get speeds above 15-20 MBit/s even though the connection shows up as 108 Mbps in the network connections dialog in XP. This is when the computers are placed side to side (optimal distance).
Another question: Is there USB equipment for the Pre-N networks? Is Belkin the only manufacturer?
They may NOT work at their best when close together, try max distance but still within the room and without encryption.
Although other manufacturers have, or will shortly have, MIMO AP's and adapters but as yet there isn't agreed standard, so it will be trial and error to see which kit works with another one. Regards, Martin
I've tried all possible distances between the wifi components..
Also, the Belkin PC-Card is a Pre-N card. To the best of my knowlegde, WEP was not activated.
I get approx, 16 Mbit/s max and that's pretty constant, it never seems to get higher even for a very short period of time.. Very odd. It seems to stay on that 16 Mbit/s level for normal usage as well, ie. doesn't dip below 16Mbit/s too often.
Ps. When using a 802.11g PC-CARD the speed maxed out at 11Mbit/s. Quite odd that too, isn't it?
Do you have the latest PC Card driver? Do you have G only turned on on the router? Have you tested from 10 feet? Do you have any other 2.4 GHz equipment such as microwave or portable phone nearby? What is the speed of your laptop? Have you tried a speed test with just one computer cpnnected? Is anyone else in your area connecting and you don't know it?
Note that the original posting was for a Belkin Pre-N access point and an unspecified client radio which I assumed to be an "ordinary"
802.11g client. Also note that the test was performed "side by side" which I presume would be under ideal conditions. If you're only getting 1/4 to 1/3 of the connection speed, then methinks something is broken in your setup.
From one of my previous postings...
I keep getting asked "how fast can it go" type questions. Perhaps some numbers might help. This is stolen from an Atheros PDF at:
some additions and corrections by me.
Non-overlapping Modulation Max Max Max Channels ------- | Link TCP UDP | | | | |
The paper claims that encryption is enabled for these calculations, but my numbers seem to indicate that these number are for encryption disabled. Dunno for sure. The Max TCP and Max UDP are the theoretical maximum thruput rates.
Well, I can arrange to get far LESS than 1/3 or 1/4. With 802.11g and a 54Mbit/sec connection, I can usually get about half that up to about
10-15 feet away using the stock antennas. If I move away furthur, the signal gets weaker and the access point slows down. Eventually, if I go far enough away, the thruput will drop to about 1Mbit/sec before it dies.
If you quote 12-16Mbit/sec "typical" performance, you should also check and disclose the connection speed and test configuration. I just tried a customers laptop in my office. 27Mbits/sec from a Dell
5150 to a WRT54G at a distance of about 6 feet. 54Mbit/sec connection. That's about 50% of the connection speed which I consider to be typical.
However, when I took the laptop outside, and going through two walls, the connection speed went down to 18MBits/sec OFDM and the thruput dropped to about 8.5Mbits/sec. Again, this is about 50% of connection speed.
Incidentally, I was using Netstat Live for performance testing:
My 54g delivers 26-27Mbps in near proximity to the WAP. Fifty feet and a couple of walls away, the "current bandwidth" in perfmon.msc bounces around on my 802.11g connection, almost like a signal strength indicator, between 240000 and 48000.
I have tested with iperf to a wired desktop, and timed file transfers.
I would agree with Jeff that it is around half of the link speed, which is consistent with the throughput I was seeing in 802.11b as well.
Good that you're enjoying that kind of access. My point, though, is that most routers rated at 54 will run at a real-world 12. Also, routers rated at
108 or 125 will run at about 35 - 40. That's in normal conditions without a lot of interference from maybe 10 feet (some routers will run slower from shorter distances). I've tested 60-70 routers under all conditions, so I'm just saying the average is 12. For example, the Apple Extreme G runs at 12. And most of the networking companies -- as much as they talk about fast access and theoreticl speeds -- will quote realistic numbers like 35 for MIMO and 45 for Super-G.
Methinks you missed my point. The TCP thruput is a roughly a fixed percentage of the connection speed. 40% to 50% is typical. The connection speed varies with the S/N ratio and BER (bit error rate), where the system intentionally slows down to keep the BER within usable limits. You can't just say "it runs at 12Mbits/sec" without specifying the connection speed or at least the conditions of the test. There are no "typical", "average", or "all" conditions. More bluntly, any test conditions without numbers is worthless.
For example, I have a typical 2 year old laptop running an unspecified
802.11g wireless card to a commodity access point across the room. Based upon your experience, what thruput should I be getting? Notice that it would be almost impossible to predict without knowing the make and models, antenna arrangements, range, reflective surfaces, interference potential (glass wall facing the city), type of benchmarking software, or protocols used (TCP vs UDP, VPN, WPA, WEP, PPTP, etc). All I'm asking is that if when proclaim that "most routers rated a 54 will run at a real-world 12", that you specify approximately under what conditions and distance the number was obtained. At the very least, specify if the stated speed is with indoor (no walls), office (some walls), or outdoor, use.
For what it's worth, the office next to mine has an Apple Airport Extreme 802.11g. When I test their laptops (mix of iBooks and Dell
51xx laptops), they all work between 20-30Mbits/sec. The range is between 6 to 15ft. However, there is one old Micron PIII W2K laptop that only does about 10-12Mbits/sec that I've been unable to obtain faster performance. Since it's always on the road, it's been difficult to confiscate and fix. The user doesn't seem concerned as it's fast enough for his use.
Incidentally, in another thread you seem to believe that the thruput and performance are heavily dependent upon the processor. That may be true for really ancient laptops and computahs, but just about anything faster than a Celeron 300 will do 25Mbits/sec thruput with any 802.11g access point up to about 10ft. More specifically, my ancient Micron Transport 2 300Mhz PII laptop running WinME and a DWL-G630 rev B1 talking to a DI-624 does it nicely.
Under ideal conditions, I get thruput equal to about 50% of the connection speed. If I add interference, the percentage will drop.
I ignore the labels and marketing hype. 50% of the connection speed at best. Anything you do beyond that makes it worse, such as adding
802.11b clients, inter fence, reflections, obstructions, other co-channel users etc.
I only have one point to make. Don't throw numbers into an answer unless you are prepared to substantiate where you obtained those numbers and under what conditions. I don't think that's too much to ask.
How fast does my car go? Mine goes about 30 miles per hour on the average. How much does that tell you about how fast *YOUR* car will go. However, if I specify the conditions under which I came up with
30 miles per hour, you might be able to consider the 30 miles per hour as useful information.
In engineering, I work with benchmarks and reproduce able numbers. When I put on my marketing hat, I work with expectations, perception, and a large collection of intangibles. I literally have to do a personality change to make the transition.
Timed file copy and various benchmarking programs running on a test PC. Find a big file. Time how long it takes to download. Do the math. It's not terribly accurate, but good enough. However, I goofed (memory fault). I think it's 15-20Mbits/sec, not 20-30Mbits/sec. I'll check again when I get to my office tonight.
See the graph at:
mbits/sec for Airport Extreme at 3ft. You don't need Super-G or Afterburner to get 20Mbits/sec. I get that up to about 10ft. However, I cheat. The airport base station has a hang on antenna to improve the signal.
I haven't done any Belkin Pre-N testing, so I'll take your word for it.
Incidentally, I avoid the term "real world tests" as it reeks of anecdotal evidence and irreproducible results. By avoid, I do use the term where there is no way to predict or calculate performance, but much prefer reproducible benchmarks and detailed calculations. I don't expect everyone (or anyone) to agree or adopt my personal preferences, but it would be nice. May I humbly suggest that if you insist on offering "real world test" results, offer them as a range of expected values, that cover perhaps 1 or 2 sigma bell distribution of probably conditions. Methinks that would be a bit more believable than a single number.
This doesn't make any sense. So, it's 50% at best and lower with interference. Huh?
You're talking about test conditions and results, I'm not. I'm talking about general 54, 108, and 125 labels on boxes and what the real world results will most likely become. Your approach is good for a specific router, PC Card, environment, and such. Mine is just a general "it's about 1/3 or 1/4 of what the box label says."
I think it's kind of funny how you are asking me questions. It's like this. If I said, when you go into that forrest, you might bump into a tree because they are close together. So, you are dismissing that general advice by saying, what is the size of the oak trees versus the maples, and what is the specific diameter of each tree. Then, you throw out this blind question for me: I bumped into a tree, can you tell me what kind it is based on all your (ahem) "research." Huh, can you? Well, no. I never said I was talking about trees, I'm talking about the forrest.
In wireless, there's either "this is what you might expect, maybe, something to think about" or there is benchmarks on specific products under certain conditions.
So, how do you know how fast the throughput is on that iBook? Because I know you are not using Ixia products. And the Apple Extreme G is not *capable of running at Super-G or Afterburner speeds, so I think you are confused about the testing results.
There's a context to that thread that you didn't include here. In real-world tests, the Belkin Pre-N runs at a suprrisingly different speed based on the laptop you use. That doesn't mean the laptop is always such a huge factor for every router.
In (ahem) real world tests, you'll get 1/3 to 1/4. If you get half, it's because you are a) adding antennas, b) not testing correctly or c) fudging the numbers.
That's why you're an engineer and I'm a writer. People want to understand things, not wade through meaningless statistics. That's why, when I say most standard G routers run 12 Mbps, it's useful information. And that's why when I say Super G goes 45, MIMO goes 35, and Afterburner goes 40, it's something that can guide people. So, in your car analogy (I prefer the trees example myself), I would say most street cars can go 55 with no problem. Then, the consumer can say, oh - so it's not a suped up sports car that can go 150, or a junker from 1972 that can only go 45 in third gear -- I'm interested, thanks for the adivce, gotta go see my Lexus dealer.
You're running a program on a PC to test an iBook? Interesting. Also, not accurate. The only way to test is with Kismac, AirStumbler, or some other tool that at least gives you a percentage of signal strength and a quality indicator. But there's no QCheck for Mac (yet).
I can dig out more if you want them. 54Mbit/sec connection yields about half that in thruput.
Reminder... your first reply in this thread was:
"Conventional G is 12 - 13 Mbps. (...) "It's never half, more like 1/4 or 1/3."
Wanna amend that in view of numerous 802.11g benchmarks demonstrating approximately 40-50% thruput?
I think you had better ask your people what they want. The one's I know, that I work for, and most of those in this group want explanations. Judging by the email I receive, many want even more details. Personally, I find one-line unsubstantiated answers to be less than useful. For example, in another thread, you basically suggested to the OP that he toss his Sony Vaio and purchase Wi-Fi certified hardware. That style of answer is no better than RTFM or "search Google".
However, you are correct that there is a class of client and reader that "just wants it to work". No understanding is needed or desired. Tell me what to change and I'll get on with life. You're absolutely correct that my style of writing is not for this type of person. I try to avoid them, but they're everywhere. I have clients also like that, who don't want to listen to explanations, or are too busy to be concerned. I generally have problems with them in that things have to be done over and over and over again. In most cases, they don't want to learn how to do anything on their computah because it's so much easier to just ring my cell phone in the middle of the night. I charge for the effort and they're happy. If this is your target audience, I wish you great success as it seems to be a growth market. But, I don't really want to participate in delivering unsubstantiated conclusions, irreproducible results, and magic numbers from nowhere.
Incidentally, I judge my acquaintances and friends by their willingness and ability to learn. I don't care what they already know and I don't care about their IQ. If they're learning, I try to help. If they stagnate in some manner, I leave them to their own devices.
Touche. I guess is you specify the hardware or vehicle, it might be useful information. I live in the mountains and driving fast is not an option with my ancient pickup truck. Actually, I just realized that I can dive into my GPS logs and give you almost exact numbers. For the path 3 days, my top speed was 55 mph. The truck was moving for 5 hours in the last 72 hrs over a distance of 55 miles. Therefore my average moving speed was 11 miles per hour and my average overall speed was 0.069 miles/hr. Isn't that more useful?
There is a relationship between signal quality (S/N ratio) and thruput. However, I'm only interested in the final output. I don't need to know the S/N ratio to measure the signal strength. It's nice to know S/N, connection speed, protocols used, encryption, etc, but not necessary.
Frankly, I don't know much about OS/X and Mac's. However, I do know and love Unix. So, I dive into the shell (terminal window) and use ftp, rcp, and possibly rcmd for remote benchmarks from the command line. For UDP testing, I just cat a big file to an IP socket that ends in either /dev/null or a named pipe to a counter program. No wiz bang gui-fied program needed. If I'm really in a rush, I'll fire up Windoze (NETBIOS over TCP/IP) file sharing and just time and copy a known file size. No big deal. In this case, the test was to an Airport Extreme with a Dell 5150(?) laptop plugged into the LAN port (through a switch) via ftp. PC's do talk to Mac's and versa-vica.
When I get busy, anything without a dollar sign in front of it gets ignored including this discussion. At this moment, I have the time.