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Be careful when mixing wireless Ethernet devices

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Mark Wilson

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It’s well known that the proprietary extensions employed by some vendors to increase the speed/range of their wireless Ethernet (IEEE 802.11) equipment can cause issues (and sometimes refuse to work with one another at all); however there is something else to consider when working with older wireless kit – the network will automatically slow down to match the slowest device. Added to the fact that wireless networks already share bandwidth (WiFi is not switched), even a fast network could well have dropped to the lowest common denominator and may be operating at 11Mbps (or slower) because of a single 802.11b adapter.

When I upgraded my wireless network to 54Mbps 802.11g, I left my wife’s PC untouched because I didn’t want to inadvertently affect her business. When I finally upgraded her PC this evening I removed the legacy Compaq WL110 card and saw an instant improvement in file transfer speeds across the wireless link from our office to my server!

With high-speed 802.11n (draft) equipment coming onstream, it’s important to remember that upgrading the network is not enough and for the full benefits to be achieved will be necessary to upgrade every connected device too – including all those laptops with built-in wireless capabilities – potentially a very costly exercise.

Comments

2 responses to “Be careful when mixing wireless Ethernet devices”

  1. Mike Breach avatar
    Mike Breach

    Is this strictly true? I have multiple devices connected to my wifi router they’re all ‘g’ capable, but the connection speed varies depending on how close the device is to the router. (Note: I haven’t done any testing, just observed the connection speed pop-up).

  2. Mark Wilson avatar
    Mark Wilson

    Hi Mike,
    You are correct that as devices are further away from the access point the speed will decrease (e.g. I get a lower-speed connection in my living room than next to the access point in my office); however a single 802.11b device is enough to mean that all the 802.11g kit will never achieve more than 11Mbps (even if it’s physically placed next to the wifi access point!).

    In my example, my wife’s PC is about 2.5 metres away from our wireless access point and when I backed up her data (over a combination of 802.3u/ab wired and 802.11b/g wireless) it took about 30 minutes but when I restored the same data (over the same 802.3u/ab and 802.11g link but now with the 802.11b device removed) it only took about 6 minutes. Other traffic on the LAN at the time would have been negligible.

    Mark

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