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View Full Version : Does a single 802.11b PC ruin the whole 802.11n network?




rjp
Apr 9, 2008, 02:21 PM
I am considering buying an airport extreme basestation, but I read the following information on apple's website that seems to indicate that if there are any slower computers connected (via 802.11 b/g) the speed of the whole network goes down.

Is this true? If I have two 802.11n computers on the network, and a single 802.11b computer joins the network then the entire wireless network speed drops to the lowest common denominator (802.11b) ? This would be very bad.

Thanks for any clarification
Rich

-----------Excerpt from Apple.com---------------

1) Based on a comparison with Apple's 802.11g products. Comparison assumes AirPort Extreme network with 802.11n-enabled computer. Speed and range will be less if an 802.11a/b/g product joins the network. Accessing the wireless network requires an AirPort or AirPort Extreme enabled computer or other Wi-Fi Certified 802.11a/b/g-enabled computer. Actual performance will vary based on range, connection rate, site conditions, size of network, and other factors. Range will vary with site conditions.



NewSc2
Apr 9, 2008, 02:29 PM
No, it won't, unless you are accessing files off of the 802.11b computer.

jsm4182
Apr 9, 2008, 02:35 PM
Its trying to say that 802.11a/b/g computers won't be able to take advantage of the extra speed and range of the 802.11n router

scienide09
Apr 9, 2008, 02:39 PM
I think it's the case that the n-enabled computers will drop. They will no longer operated a n-type connectedness but will instead drop down to the 802.11g area when anything other than an n-enabled device is connected to the network.

rjp
Apr 9, 2008, 02:39 PM
No, it won't, unless you are accessing files off of the 802.11b computer.

So the 802.11n PCs will always be served at highest (n) speed from the wired ethernet for example?

This is good news, but if true, then I think Apple's disclaimer should be reworded to indicate that if an 802.11b device joins the network speed will be reduced *only* on communications directly involving this device.

yellow
Apr 9, 2008, 02:41 PM
From what I understand:

Unless something has changed drastically, a mixed a/b/g wireless router will always default to the slowest protocol designation, depending on what devices are using the wireless router.

e.g., And 802.11g wifi signal from a wifi router that supports b/g will scale back to 802.11b if a device with only 802.11b capabilities connects to it. Screwing everyone else on the signal.

Is this not true in 802.11n?

rjp
Apr 9, 2008, 02:44 PM
I think it's the case that the n-enabled computers will drop. They will no longer operated a n-type connectedness but will instead drop down to the 802.11g area when anything other than an n-enabled device is connected to the network.

Oh. That's not good news. Unfortunately the Apple sight has the same disclaimer for 802.11g routers if an 802.11b device joins the network! So it's not just "n". Even the "g" service may drop to "b" if a single slow device joins?

Hopefully it is only for communications directly involving the slow device, but on the otherhand, it does make sense technically that the entire air interface must be modified to serve the lowest speed device.

coledog
Apr 9, 2008, 02:44 PM
Nvm, wasn't fast enough...question asked.

yellow
Apr 9, 2008, 02:47 PM
Even the "g" service may drop to "b" if a single slow device joins?

Hopefully it is only for communications directly involving the slow device, but on the otherhand, it does make sense technically that the entire air interface must be modified to serve the lowest speed device.

I am pretty sure that 1 slow devices sours it for everyone.

Lord Blackadder
Apr 9, 2008, 02:50 PM
I have a new Airport Extreme. My PowerMac G4 has an original Apple AirPort 802.11b card, and my PowerBook has an Airport Exreme 802.11g card. Both operate in "b" mode when the PowerMac is running.

skorpien
Apr 9, 2008, 02:52 PM
From what I've read, it does slow down the network when the b device is accessing it (not completely to b speeds though), but it will speed up again when the device stops. There are a couple of ways to make sure this doesn't happen though. Set up a dual band network (using another a bridged router to host b devices and making the AEBS n-only 5 GHz), or hardwire your b computer to the AEBS. I have a TC (n-only 5 GHz) with a Linksys b/g bridge and it's working great.

mikes63737
Apr 9, 2008, 02:53 PM
I am pretty sure that 1 slow devices sours it for everyone.

You're absolutely right.

Your best bet would be to not use wireless for the 802.11B computers (use ethernet cables), or buy an AEBS for your N-enabled PCs and then some Linksys or Netgear access point for the non-N PCs and then connect the two.

coledog
Apr 9, 2008, 03:05 PM
Any way to use WDS and have one be N and the other G with on AEBS being the G version and the other a N version?

skorpien
Apr 9, 2008, 03:10 PM
Any way to use WDS and have one be N and the other G with on AEBS being the G version and the other a N version?

You're still going to get slower speeds. Not only that, but every "hop" in a wirelessly extended network effectively cuts the speed in half.

rjp
Apr 9, 2008, 03:21 PM
You're absolutely right.

Your best bet would be to not use wireless for the 802.11B computers (use ethernet cables), or buy an AEBS for your N-enabled PCs and then some Linksys or Netgear access point for the non-N PCs and then connect the two.

How do you set this up?

Also, is there a way to tell AE to only accept n-enabled devices so the slower machines can not connect to it?

I have a new Airport Extreme. My PowerMac G4 has an original Apple AirPort 802.11b card, and my PowerBook has an Airport Exreme 802.11g card. Both operate in "b" mode when the PowerMac is running.

How can you tell if you are operating in "b" mode?

iPhil
Apr 9, 2008, 03:24 PM
Oh. That's not good news. Unfortunately the Apple sight has the same disclaimer for 802.11g routers if an 802.11b device joins the network! So it's not just "n". Even the "g" service may drop to "b" if a single slow device joins?


That's true unless your using the 5Ghz N only stream then only the N devices will access the network....



If the radio mode is: 802.11N (802.11 g/b compatible), then it'll clock-down the wifi speed to the slowest wifi device that currently connected to the network..

If you go 802.11N (2.4Ghz) then you get the same distance as the g/b compatible network but only N devices will see the network...



If you go 802.11N (5Ghz) then you get the double to triple distance** as the g/b compatible network but only N devices will see the network...


** - it depends on the conditions around the network..

rjp
Apr 9, 2008, 03:47 PM
What happens in the case of a 802.11g network when a 802.11b device joins?

Is it certain that the whole network will drop to 802.11b?

or just when communicating directly with the slower device?



That's true unless your using the 5Ghz N only stream then only the N devices will access the network....



If the radio mode is: 802.11N (802.11 g/b compatible), then it'll clock-down the wifi speed to the slowest wifi device that currently connected to the network..

If you go 802.11N (2.4Ghz) then you get the same distance as the g/b compatible network but only N devices will see the network...



If you go 802.11N (5Ghz) then you get the double to triple distance** as the g/b compatible network but only N devices will see the network...


** - it depends on the conditions around the network..

yellow
Apr 9, 2008, 03:50 PM
Is it certain that the whole network will drop to 802.11b?

Yes. The wireless router will support the slowest possible speed, based on connected device, to the detriment of all other connected (faster) devices, IF the router is in mixed mode.

Lord Blackadder
Apr 9, 2008, 04:55 PM
How can you tell if you are operating in "b" mode?

The download speed drops on my PowerBook.

iPhil
Apr 9, 2008, 10:50 PM
Is it certain that the whole network will drop to 802.11b?


Yes. The wireless router will support the slowest possible speed, based on connected device, to the detriment of all other connected (faster) devices, IF the router is in mixed mode.

What yellow is saying is correct.... If you want the N-Speed provided by AE-N then you need this lil unit (http://eshop.macsales.com/item/Edimax/EW7718UNOB/) on all wifi devices that aren't N speed ready...


Then just change the radio mode: 802.11N (5 Ghz)... Done..

rjp
Apr 10, 2008, 08:54 AM
The download speed drops on my PowerBook.


How can I tell what speed my wireless network is running at?

Is there an indicator on the mac somewhere?

I logged into the router (netgear) and did not see a speed indication.

I would like to know if it is operating in "g" or "b" mode, and I want to see this change when "b" devices join.