Mailing List os2-wireless_users@2rosenthals.com Archived Message #3810 previous message next message back to list

From: Lewis G Rosenthal <os2-wireless_users@2rosenthals.com> Full Headers
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Sender: os2-wireless_users-owner <os2-wireless_users-owner@2rosenthals.com>
Subject: [OS2Wireless] 802.11g
Date: Mon, 07 Feb 2005 20:33:36 -0500
To: os2-wireless_users@2rosenthals.com

My web guy was so excited when he found a 108Mbps DLink AP... Imagine how downtrodden he became when I explained to him that even our cable connection is only 2-3Mbps, and there ain't no such thing as 108Mbps Wi-Fi (it's a dual channel model, so it sends on one channel and receives on the other; a nice sleight of hand, but you need to have a DLink WLAN card in order to make use of it, as it's a completely proprietary implementation...I hate when people get hoodwinked into spending more $$ than they need to).

Neil, as you've correctly pointed out, 802.11g is fully backward compatible to 802.11b (unless 802.11b clients have been specifically locked out of the AP). In fact, while all the hotspots we're now deploying use 802.11g AP's, as per the standard (the "standard" refers to the behavior, not the 11g APs!), as soon as a single 802.11b (yours truly, usually!) gets on the WLAN, everyone slows to 11Mbps maximum bandwidth. And you know...? We haven't had one person come up to any of us and ask what happened to the throughput.

When will it really make a difference? When there are (for example) 10 WLAN users on the network with a single AP. 11g typically puts out 22Mbps or so (yes, I know I've probably opened a can of worms with that statement, and everyone will start jumping all over me, but in truth, 11g drops off rather quickly, especially in public spaces with lots of heavy metals - refrigerators, freezers, and ovens, to name a few - in the area). So, if you consider that WLANs are like hubs and not switches, if unmanaged (the Sputnik software allows us to throttle users - hey, I know of a few users I'd like to throttle! - but this is atypical of most APs) each user receives an equal amount of the available bandwidth. So, with ten users on an 11g network, with a 22Mbps average throughput, each client would receive approximately 2.2Mbps of bandwidth. Compare that to an 11b WLAN, where each user would get a maximum of 1.1Mbps (typically a little less). You might not notice it for regular browsing, but downloads and streaming media might be affected (I'm constantly amazed by the amount of data people pull down at the hotspots; again, the Sputnik Control Center is pretty neat in that it will give me minute-by-minute reports of how much traffic has gone up and down to a particular station...one Sunday, I guess someone was downloading CD images, because there were hundreds of megs coming down to one user's station).

Anyway, I'm way long winded tonight, so please forgive me (everyone). I've been down with a really lousy chest cold the past couple days, and I'm finding myself rambling this evening...maybe it's the meds... :-)  Oh, and apologies to those who might be offended that I'm sending this post from my Citrix server running Wintendo 2K Advanced Server (hey, at least I'm using Thunderbird!). I need to work in the lab on - you guessed it! - yet another couple of buggy, bloated Wintendo machines, so I'm pretty much strapped in here for the ride. One more quick follow up to my earlier post, and then I'm back to work...

Neil Waldhauer wrote:

On Tue, 08 Feb 2005 00:12:25 +0100, "Massimo @ eCS.it" <massimo@ecomstation.it>
wrote:

 

802.11b is so slow and obsolete to be quite useless nowadays...
   


Maybe so in Italy. But in USA, it is 802.11g that is useless. A cheap
connection is likely to be DSL or a Cable modem in the USA. Both these
connections are far slower than 803.11b, at least for most subscribers. So, for
all the connections I'm likely to see, 802.11b is exactly the same speed as
802.11g.

While I support the concept of the faster standard, 802.11g, the devices
running it always fall back to 802.11b, so I don't ever see any difference. So
for the present, I am quite happy with my 802.11b support.

I hope that we get to try GENMAC, once it is ready, in this group, along with
an XWLAN that gives us access to the newer features of the drivers.

Neil
 


--
Lewis
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Lewis G Rosenthal, CNA, CLE Rosenthal & Rosenthal Accountants / Network Consultants  New York / Northern Virginia           www.2rosenthals.com
Team OS/2  / NetWare Users International      www.novell.com
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