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College to Deploy First 802.11n Network
Matt writes "Morrisville State College, a New York State school in central New York, is partnering with Meru Networks and IBM to deploy the first 802.11n wireless network. They will be using around 900 access points and are planning to go live this fall."
And they go straight to the next bleeding edge : 248 mbit.
_ Amendments
They have nearly filled the alphabet btw. Only 802.11z is still free as a name. Can you name them all ? http://en.wikipedia.org/wiki/802.11n#Standard_and
The key point is the difference between bits and bytes. A 10Mbps connection is a 1.25MB/s connection.
1.25 megabytes. Remember that a generic S-ATA or IDE hard disk writes at about 5-6MB/s and that can be a big bottlencek most of the time. So the 54Mbps connection you speak of is a total speed of ~7MB/s. That's not the internet speed. That's the LAN connection. So one person tries to send a large file to another on the network and all of a sudden we've hit that bottleneck and no one can even check their email.
Although some of these numbers sound impressive realistically for daily LAN usage they are just about usable.
I never get used to these constant resurrections
A little background on SUNY Morrisville. I went there with New York Boy's State back in 2002. I never attended the school as a student so these are my impressions from staying there for a week. Morrisville is small, technical and farming college located in a really rural part central New York state. I believe that it was a 2-year college five years ago, but may now have a 4-year program. It is largely a farming college and boasts an award-winning dairy farm on campus. Ford also built an auto repair facility on campus, and I have known people go to Morrisville to learn auto mechanics. According to Wikipedia, there are about 3000 undergraduate students there and an extension campus in Norwich, NY. This makes it roughly the size of my old High School.
An enlightenment painter would paint a grand house on a lawn; A romantic painter would paint it on fire.
Exactly. I've had one here since February. Apple has sold 100s of thousands of Airports with 802.11n and others have sold a ton more too.
The 54Mbps refers to the signalling rate of the transmitter not the data rate that is acheiveable - bascially a maketing tools like MB MiB in hard drives.
The actual transfer rate is reduced from the optimum by the packetising of the data, obtaining the wireless spectrum before transmission and that an inter-packet gap is inserted between every transmitted packet to allow other AP users to transmit data.
No, Not free. There was a $600 a semester line item on my bill over 4 semesters. Students are buying a laptop for $2400. Oh, and if you drop out after the third semester, you had to pay the last $600 or give it back. The school doesn't pay anything for the laptops. The cost goes right to the tuition.
On the otherhand, in fall 2002 when I was issued my Thinkpad T-30, there was no more powerful laptop on the market, and $2400 was slightly below market prices for that particular piece of equipment.
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You can't compare bit rates of telephone and ethernet connections directly. It takes 10 bits to transmit 1 byte over the telephone because each byte has a start bit and a stop bit, which is an overhead of 25%. Over the network, everything is transmitted in 1500-byte packets with a 14-byte header and 4-byte footer; so the overhead per byte is much less at 1.2%.
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A lot of vendors, I'm not sure of the one they are using, but Cisco, and a few other major players have guaranteed their draft equipment will work with the standardized 802.11n.
In a world of acronyms, the words are the real victims.
Ehm... no.... that should be "First College to Deploy DRAFT 802.11n Network"
. 11_Timelines.htm
802.11n hasn't been ratified yet, there's no such thing as an 802.11n network at the moment.
Currently expected in september 2008
http://grouper.ieee.org/groups/802/11/Reports/802
It will be a while before someone rolls out the first 802.11n network.
TTB
Nope, hard disk speeds are quoted in MB/sec, not Mbps. You're a factor of 8 out - 40-50MB/sec is more like it (and modern desktop drives are a bit faster than that).
You've never actually used a network somebody else is using, have you? Suggesting that when one user saturates the network nobody else can even check their email is quite simply wrong. Every shared networking technology in use today shares the bandwidth out pretty fairly and with modest overhead for a reasonable number of clients. You can reach a stage where there are so many clients simultaneously using bandwidth that overall throughput suffers, but it takes a damn sight more than one person sending one file to do it. I saturate my 54Mbps Wi-Fi connection every time I back up my laptop and not only can everybody else on the network (often me using another machine) check their email, they can stream hi-def content from the interwebs, send huge files and do pretty much anything else they'd normally do too. With at most half a dozen or so clients on my AP I've never seen overall throughput drop, the bandwidth just gets shared out fairly between the clients. If two try to send big files, of course they only get half the bandwidth each, but it still works just fine. With 100 clients doing P2P it would be a different matter.
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Because of the overhead, a single 54Mbps wireless connection, if on .11a or .11g only, can get as high as about 30Mbps. If there's a .11b device in range and a .11g AP is set for compatibility mode, it can knock the rate down to 10-15Mbps.
.11n, the theoretical rate actually maxes out at about 250Mbps. Factoring in the overhead, this allows, without compatibility mode, perhaps 150Mbps. However, the presence of any pre-.11n device knocks the channel width down to 20MHz from 40MHz, and then compatibility mode with .11a/b/g can knock it down even lower. Chances are that the actual bitrate with a relatively clean signal will be ~125Mbps, and the actual throughput will be somewhere around 70-75Mbps.
Under
One thing to keep in mind in all of this is that in many cases, the uplink on a switch to the rest of the network is only 100Mbps, so the final throughput from what people are used to isn't going to decrease all that much. Factor in several APs with a balanced channel setup with a gigabit uplink, and the experience shouldn't be all that different from what the wired people are experiencing.
You can never go home again... but I guess you can shop there.
You're mixing up your layers there.
The modem's encoding a byte with 10 bits would be at layer 1.
Over that, you'd have Ethernet, with its own overhead (the 14+4 bytes you mentioned), PPP, etc, at layer 2.
Over that, you have IP, with a 20 byte header, layer 3
And over that, you have TCP, with a 32 byte header, layer 4.
Not to mention that those 1500 byte packets are only 1500 bytes when transferring large amounts of data. Something with small packets like SSH gets more overhead.