108Mbps vs. 54Mbps

Hello guys. I'm fairly new to wireless tech, but have set up a few basic systems for some of my customers. I have just purchased a laptop for my wife. The computer has Intel® PRO/Wireless 2200BG internal network card. I purchased a D-Link DI-624 108 Mbps High Speed 802.11g Wireless router. The router was DOA and the store I got it from is an hour away. I ran down to the local Radio Shack and got at Linksys WRT54G 2.4Ghz 802.11g wireless router. My question is if it is as fast. It claims a speed of 54Mbps or half as fast as the D-Link. Is true that my connection speed is half as fast or is the issue range, and finally is the internal card capable of receiving 108Mbps? Thank you guys for clearing some of this up for me.

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The "standard" for the 802.11g is 54Mbps. To get beyond that each manufacturer uses different technology to "enhance" the signal. No two manufacturers use the same technology to do it. You could have bought a WRT54GS and gotten the 108Mbps but ONLY with another Linksys card that supports "speedboost".

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the 108Mbps of your d-link router only works with a d-link 108mbps enabled wifi card. thus if your wifes laptop uses its internal wifi card, it will work at

54Mbps mode nomatter d-link, linksys or any other 802.11g router.
Reply to
Ali Babba

"Mad_Unit" wrote in news:1108562129.985780.18290 @g14g2000cwa.googlegroups.com:

You'll need a Dlink 108mbps card to get the full speed.

Also, with WiFi, I doubt you'll get probably 30 - 40% of the rated speed. So with a 54mbps AP, expect about ~20 - 25mbps. With a 108mbps AP, you'll get about 40 - 50mbps. Don't expect to hit 108mbps, you'll need a wired LAN for that.

Reply to
Lucas Tam

The data rates for 802.11a and 802.l1g that are higher than 54 Mbs are achieved by manufacturer proprietary schemes. To take advantage of the proprietary schemes, both the Access Point and Client hardware will have to be from the same manufacturer and capable of their manufacturer-specific "turbo" scheme. Some manufacturers claim upwards of 72 Mbs, while others (D-Link) claim upwards of 108 Mbs. I'm using D-Link stuff that claims 108 Mbs for both 802.11a and 802.11g. Of course, the actual throughput is no where near 108 Mbs. These claims are based on the max rate possible (in theory) in RF clean lab conditions.

Even though the "turbo" doesn't come close to what it's claimed, I've found that it does give about 30 percent boost over vanilla 802.11a with my D-Link stuff, which I'm happy with. Can't say about 802.11g as I don't have any client hardware 802.11g.

Keep in mind that the proprietary "turbo" schemes, while giving some modest "boost", will also introduce new limitations. With "turbo" enabled, your wireless range is somewhat reduced. Can't speak for the other manufacturers, but with D-Link using "turbo" requires that your center frequency for "turbo" to be on channel 6 -- which may be more prone to interference. Also, (at least with D-Link), you have two options for "turbo" that are either dynamic or static. With "dynamic turbo", if you have a "turbo enabled" connection established and another connection (non-turbo) is established, then everything will drop back to vanilla

802.11a/g. With "static turbo", only hardware capable of "turbo enhanced" connections will be permitted to connect.



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That statement is not quite true. You do not necessarily need a DLink

108mbps enabled wifi card to obtain such speeds in conjunction with the DI-624 wireless router. I am able to obtain such speeds using my Netgear WG511T card when used with the DI-624 and the DWL-2100AP.
Reply to
Doug Jamal

I just recently bought a Linksys WRT54GS like you talk about here, and the matching wireless card for one of my computers. For the first two weeks of operation, I was getting 125 Mbps showing up on the network monitor. It rained ( and thunder and lightening) for the first time since I've owned the setup yesterday, and the connection speed dropped to 54Mbps. I changed the transmit channels, and the signal speed went back up, but this morning, it's back to 54Mbps. The access point and the computer are less than 3 feet apart, with a half-wall spearating them. Anyone have any ideas?

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I forget the exact reasons/setting, but sure somebody here can tell you what it is. While the link starts out at the highest speed, the first time it gets a certain number of errors, it drops to a lower speed to try and keep on going error free. But it never increases the speed again. I have heard people say that after a while it will even keep going down and down in speed, until they reconnect/restart.

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Peter Pan

As someone else replied, the data rates over 54 Mbs are usually proprietary mechanisms. I'm using D-Link and not overly familiar with Linksys, but there are some settings with D-Link that cause what you are seeing. With D-Link, on the AP's that are capable of their proprietary 108 Mbs "turbo" mode there is an option for the turbo to be either dynamic or static. If it's set to "dynamic", then connections can be made to the AP with turbo enabled or disabled on the client's end. If any client connects to the AP without turbo in use, then turbo is disabled for all connected clients -- regardless if they can support it or not. Also, the signal has to be relatively strong in order for turbo to be used. If it is set to "static", then only clients capable of "turbo" are permitted to connect. If there are no "non-turbo" clients connected, check the signal level when it "drops" to

54 Mbs. May want to try moving the two as well. It could be possible that three feet apart, even through the half-way, is too close.

As for the true data throughput, 108/125 Mbs (and even 54 Mbs) are more marketing numbers than anything else. Thats the theoretical max throughput if used in an RF clean lab. Real world use, of course, is much different. Do a google for a program called "NetPerSec". Its a small little program that will give the actual data throughput. If you can, try to hunt down version 1.1 -- as that version not only gives current data throughput, max data throughput, but also an average. Unfortunetly, I don't remember the exact location that I found this version at (took some digging) other than it was on an Italian website.



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