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Wireless Networking at 72Mbps

Posted by Hemos on from the going-super-fast dept.

Unknown Relic writes "One of the biggest drawbacks to current wireless networking technologies is the limited connection speed. Well now LinkSys has released a new wireless access point which operates on the 5 GHz band, supports up to 72 Mbps connections and is fully interoperable with existing 802.11a wireless equipment."

12 of 146 comments (clear)

  1. Research! by a3d0a3m · · Score: 2, Informative
    For anyone interested, here's a research article that outlines the development of the wireless system mentioned in the article. The second reference is to their major source of inspiration. Funny how it takes over 5 years from research to mass-consumerism, huh?

    Lopes, B. J. (Apr 1997). Wireless Networking in the 5GHz band. Dissertation Abstracts International: Section B: the Sciences & Engineering, 57 (10-B), 6653.

    Trafimow, D. (Dec 1996). A proposed system for intermessaging and communication above current bandwith limitations. Journal of Applied EE, 26 (24), 2167-2188.


    adam
  2. One of the biggest drawbacks? by Anonymous Coward · · Score: 5, Informative

    Contrary to the post, I would argue that connection speed isn't one of the biggest drawbacks. Rather, it is the lack of standards and interoperability.

    Testing reveals that most of these "802.11a" access points are not compatible with each other. Only identical products work together. So when your vendor EOLs (End of Life's) your AP, further expansion of your network becomes a problem.

    1. Re:One of the biggest drawbacks? by Albanach · · Score: 2, Informative

      We've had a few problems earlier with interoperability, but our more recent wireless network hasn't encountered any problems. Isn't this the whole point of the Wi-Fi standard - everything bearing the Wi-Fi logo should be interoperable. As you say though, the 10mbit bandwidth is often sufficient - after all, in the majority of implimentations, it's to allow access to the office network, and at least around here (Scotland) there aren't many offices with internet connections running at more than 1 or 2 mbits.

  3. 802.11a at 108Mbps by calc · · Score: 5, Informative

    Several companies have announced 802.11a cards that use two channels and get up to 108Mbps. But as The Register article mentions there is considerable overhead with wireless ethernet. 802.11b (11Mbps) typically gets 5Mbps real bandwidth, 802.11a (54Mbps) gets 23Mbps real bandwith, and 2 channel 802.11a (108Mbps) gets 34Mbps real bandwidth.

    http://www.theregister.co.uk/content/archive/227 31 . tml
    http://presslink.dlink.com/releases/pr01-07-0 2.htm
    http://www.proxim.com/products/all/harmony/ 8450/

  4. D-Link and Proxim by Kohath · · Score: 4, Informative

    DLink is also selling a 72 Mbps version, and Proxim is selling a 108 Mbps version of this same product.

    I'm using the D-Link. It works, but I haven't benchmarked it for speed. It says it connects at 72 Mbps consistently.

    Intel and SMC sell 802.11a equipment too. The Intel one is limited to 54 Mbps. Not sure about the SMC.

    Best thing for me is that it doesn't interfere with my analog 2400 Mhz devices because it runs at 5 GHz.

  5. Speeds. by saintlupus · · Score: 4, Informative

    is fully interoperable with existing 802.11a wireless equipment.

    Uh, no kidding. The 802.11b standard is the slower, ~11Mb/s one. 802.11a is specced to be faster. The Linksys product is just a regular access point for 802.11a.

    Is this one of thaose Slashvertisements I've been hearing so much about?

    --saint

  6. Range, range, range by march · · Score: 2, Informative

    And, if it has the range that 802.11 is *supposed* to have, we'll all be happy. But, if it behaves like current wireless devices, I'll need two WAP's in every room of my house.

    Imagine my disappointment after reading about 802.11 and getting a WAP and card for my Zaurus thinking that I could walk around my block with an instant messenger app running. As Topsy says, "Forget about it!" I couldn't walk to the other side of my house.

    As I'm sure most of you already know, beware of claims of bandwidth and range...

  7. what about dynamic WEP keys??? by Anonymous Coward · · Score: 2, Informative

    This is all fine and dandy but until the encrytpion is strong enough that I can use it on my company's internal network myself and many other admins can not consider it.

    Cisco has a dynamic WEP key solution that sidesteps WEP's vulnerabilities

    http://www.cisco.com/warp/public/cc/pd/witc/ao35 0a p/prodlit/1281_pp.htm

    and I think Proxim has a similar solution, but I don't think either solution is interoperable with other manufacturer's equipment.

    Does anyone know if there is a standard for dynamic WEP keys that works across multiple vendors?

  8. Re:Here is what I had to say to Linksys sales by flatulus · · Score: 5, Informative

    Here are a few tidbits of FACT that you can also process in your haste to flame LinkSys...

    a) Until quite recently, the only chipset available from which to build an 802.11a radio, either user or access point, was from Atheros. Now, Resonext has released a chipset and someday (soon?) Intersil will release their Indigo chipset for 802.11a. At present, you can almost be certain that any 802.11a product you can buy uses the Atheros chipset.

    b) Atheros is being VERY tight with tech specs. You most assuredly would have to sign an NDA, and probably sign a purchase agreement, committing to buy 5 to 10 thousand chips before they will THINK about letting you peek at the technical info you need to write a driver.

    c) An Atheros employee told me in March that a Linux driver was under development, and would be out in "a couple of months" (so it's due, like, now).

    d) Proxim sells an 802.11a Mini-PCI card as an OEM product. See: http://www.proxim.com/products/all/oem/9350/index. html and you will find that under "Drivers Available" they state: "Source code may be licensed to facilitate design-in for non-PC platforms." But don't get too excited. I'm sure you will have to sign an NDA and convince them you're gonna buy a truckload or two of cards. And I'm also sure you will find that Atheros has bound their hands also, with respect to low-level technical info needed to write a Linux driver.

    c) The 72 Mbit/sec "Turbo" mode is a feature of the Atheros chipset -- Linksys just inherited it by virtue of using their chip.

    And finally...

    The 54 Mbit/sec (or 72 Mbit/sec "turbo") is extremely range limited. At 100 ft, 802.11a drops back to a speed which is very close to 802.11b. But there are many reasons (other than raw throughput) that 802.11a is a Good Thing (tm), so let's look on the bright side that we have it.

    And by the way, let's tip our hats to Apple Computer for supporting the efforts in its advanced technology team to petition the FCC for unlicensed spectrum. I was there. I can tell you that Apple deserves praise for paying the salaries of people who did nothing but work toward getting unlicensed spectrum (e.g. U-NII, where 802.11a operates) available for us geeks :)

  9. Re:Let's just hope sys-admins will learn by WolfWithoutAClause · · Score: 3, Informative

    No. If you're not using VPN software you're incompetent. WEP is garbage, and SSID is sent in the clear.

    --

    -WolfWithoutAClause

    "Gravity is only a theory, not a fact!"
  10. 5Ghz Problem by marshac · · Score: 2, Informative

    The problem with 802.11a is the high frequency in which it opperates. 5ghz is just too high for anything other than line-of-sight (outdoor). The 2.4Ghz band that 802.11b/g opperate on is still high and still suffers from line of sight limitations, but in general, it fares better.

    I also have to wonder, who needs that much bandwith in a wireless application? Perhaps you should really be thinking about a wired connection if bandwith is that critical. In most applications, it's not the standard that's the major limitation, it's the equipment.....most cheaper cards are not full-duplex....so you're missing half your bandwith right there. Good equipment and antennas will serve you much better than a "better" standard.

  11. Re:diy wireless between buildings? by rcw-home · · Score: 4, Informative
    anybody have any experience running a wireless network between two adjacent buildings?

    1. Don't get two Linksys WAP11's and put one of them in Access Point Client mode. You will have to reboot that access point nearly every day because of firmware bugs (even with the latest firmware). Not bitter.

    2. Get as close to a line-of-sight path as possible. You need at least an -83dBm signal to do 11mbps, so shoot for -75dBm during install if you want to maintain -83 when people walk in front of it, it rains, etc. Shooting through glass or drywall doesn't hurt very much (I've gotten -75dBm between an Orinoco Silver and a Dlink DWL-1000AP with 10 sheets of drywall in the way and stock antennas) but thicker things like concrete really hurt. So do more than a couple trees (the drops of water that tend to hang on their leaves some of the time are opaque at 2.4ghz).

    3. If the only way to get a usable line-of-sight is to mount something on the roof, then do it, but keep cable runs to an absolute minimum and use LMR400 coax. Install properly-grounded lightning arrestors where the coax enters the roof. As for the antenna itself, you can weatherproof just about anything by putting it in PVC pipe or you could get a dish, panel antenna, or yagi from any of these people.

    4. Security - since WEP sucks, you'll want to do a VPN of some sort between networks. You'll probably want to spend a few weeks learning how IPSec works on the systems you'll be using as your routers to accomplish this. I would recommend against any of the VPN appliances as a lot of them are too stupid to do things like put the default route across the tunnel.