[krx]

A coupla networking questions:

How much will an 802.11g Airport Extreme slow down an 802.11n network?

II have an iBookG4 that I want to use on the network. I can put it on its own ethernet cable direct from the router but obviously would be more convenient not to. My question is, can i use it via wi-fi on a 802.11n network without slowing down the entire network?

Is my router slowing down my network? I have a Linksys BEFSR41 (v.2) router standing between my broadband modem and my Time Capsule. How much difference would I see if I were to remove the Linksys router and use the TC as the router?

[Simon]

Originally Posted by krx 

How much will an 802.11g Airport Extreme slow down an 802.11n network?

It depends which AirPort Extreme base station you're using. Newer models offer dual-band networking which means you can have it host two networks. One is g, the other is n and both run at their full speeds. Older models will require you to use g/n mixed mode. In my own experience mixed mode is only slower on the n device when the g device is actually transmitting. The fact that your n device is accessing the mixed mode network alone does not slow it down severely. In my own testing the n device on the mixed network wasn't slower than running it on the 5ghz-only n network. What does change however is the displayed theoretical max bandwidth. It's only 130 MBps in mixed mode. However, you'll never really achieve that anyway. Not even on an n-only 5 GHz network.

I have an iBookG4 that I want to use on the network. I can put it on its own ethernet cable direct from the router but obviously would be more convenient not to. My question is, can i use it via wi-fi on a 802.11n network without slowing down the entire network?

If you have a dual-band capable base station that's the way to go. If not try the mixed mode network and run some tests of your own. Unless the g device is constantly accessing the wireless network I would not expect to see dramatic decreases on the n device.

Is my router slowing down my network? I have a Linksys BEFSR41 (v.2) router standing between my broadband modem and my Time Capsule. How much difference would I see if I were to remove the Linksys router and use the TC as the router?

Both scenarios are possible. A good router that's properly configured should not slow you down. But I don't know if that's a good router and it's configured well. I've seen a bad router bog down a network myself, so it's definitely possible. Let me ask you this though. Is there a reason to keep the router there? Is it doing something specific? Your TC is a very good DHCP/NAT router for both wifi and LAN (via the three LAN ports on the back). It's easy to configure too. If your router isn't between the modem and the TC for a specific reason I'd remove it just for the sake of reducing complexity.

[krx]

Thanks for the detailed reply - much appreciated!

Originally Posted by Simon 

It depends which AirPort Extreme base station you're using. Newer models offer dual-band networking which means you can have it host two networks. One is g, the other is n and both run at their full speeds. Older models will require you to use g/n mixed mode. In my own experience mixed mode is only slower on the n device when the g device is actually transmitting. The fact that your n device is accessing the mixed mode network alone does not slow it down severely. In my own testing the n device on the mixed network wasn't slower than running it on the 5ghz-only n network. What does change however is the displayed theoretical max bandwidth. It's only 130 MBps in mixed mode. However, you'll never really achieve that anyway. Not even on an n-only 5 GHz network.

I have a single band Time Capsule and a single band 802.11g Airport Extreme base station. The AEBS is configured as an extension of the TC, the latter in mixed mode. Testing it on my MacBook Pro (with 'n' enabled) I got a Transmit Rate of 145 Mbps with the Time Capsule before adding the AEBS to the network, and 54 Mbps after adding it. The funny thing is that, even tho the transmit rate is drastically reduced, basic tasks like loading Web pages and checking email seem to be snappier after adding the AEBS.

Originally Posted by Simon 

If you have a dual-band capable base station that's the way to go. If not try the mixed mode network and run some tests of your own. Unless the g device is constantly accessing the wireless network I would not expect to see dramatic decreases on the n device.

What's the best way to test this? I can check the transmit rate but I'm getting the impression that that isn't the most reliable method.

Originally Posted by Simon 

Both scenarios are possible. A good router that's properly configured should not slow you down. But I don't know if that's a good router and it's configured well. I've seen a bad router bog down a network myself, so it's definitely possible. Let me ask you this though. Is there a reason to keep the router there? Is it doing something specific? Your TC is a very good DHCP/NAT router for both wifi and LAN (via the three LAN ports on the back). It's easy to configure too. If your router isn't between the modem and the TC for a specific reason I'd remove it just for the sake of reducing complexity.

I went ahead and replaced the router with the TC and did notice an improvement - although this coincided with adding the AEBS to the network (as mentioned above) so now I'm not sure which made the difference. When I get home tonight I'll detach the AEBS and see what happens...

I have an ethernet panel in the basement, next to the broadband modem, that feeds various ethernet jacks throughout the house. The router simply fed the panel. I think I will replace the TC (which replaced the router) with a new dual-band AEBS. Then I can return the TC back to my attic office where it was serving a usb-networked printer (making it wi-fi accessible.

I have an old Rev. D, 333 MHz iMac I want to set up in the basement for my four year old to play games on. I'm thinking I'll use the older single band AEBS to network the iMac. If I understand correctly this shouldn't diminish overall performance of the network running off a dual-band AEBS.

[Simon]

Originally Posted by krx 

I have a single band Time Capsule and a single band 802.11g Airport Extreme base station. The AEBS is configured as an extension of the TC, the latter in mixed mode. Testing it on my MacBook Pro (with 'n' enabled) I got a Transmit Rate of 145 Mbps with the Time Capsule before adding the AEBS to the network, and 54 Mbps after adding it.

Well in that case, since you have two sets of hardware I would suggest running the TC in n-only mode as one wifi network and then attach the Extreme's WAN port to one of the TC's LAN ports. Set up the Extreme for a second wifi network but running g. Make sure to set the Extreme to bridged mode so that the TC handles all the DHCP/NAT stuff. Now all wifi clients can connect at their maximum speed and are still all part of the same LAN, IOW they can see and talk to each other.

The funny thing is that, even tho the transmit rate is drastically reduced, basic tasks like loading Web pages and checking email seem to be snappier after adding the AEBS. What's the best way to test this? I can check the transmit rate but I'm getting the impression that that isn't the most reliable method.

That's because transfer rate is a rather abstract measure that's not directly related to real-world throughput. Mine is always 130 Mbps and I can assure you I have yet to see close to 16 MB/s real throughput.

If you're interested in real-world throughput I suggest you try transferring large files and time the transfer. Also Activity Monitor > Network can also be useful as it shows you the actual current throughput.

I went ahead and replaced the router with the TC and did notice an improvement - although this coincided with adding the AEBS to the network (as mentioned above) so now I'm not sure which made the difference. When I get home tonight I'll detach the AEBS and see what happens...

Well I think in any event you can leave the router out of it since it doesn't seem to serve any real purpose. I'd envision something like this:

Broadband Modem --> TC (n mode) --> APExtreme (g mode). Both the TC and the Extreme offer extra LAN ports for any wired clients.

I have an ethernet panel in the basement, next to the broadband modem, that feeds various ethernet jacks throughout the house. The router simply fed the panel.

Now you could plug the modem directly into one of the panel ports and then connect the TC (which will acting as your "master" router) at the other end of that line.

I think I will replace the TC (which replaced the router) with a new dual-band AEBS. Then I can return the TC back to my attic office where it was serving a usb-networked printer (making it wi-fi accessible.

You can do that. But keep in mind that per the above instructions you can use your two devices to basically achieve the same thing as the dual-band access point achieves.

[krx]

Originally Posted by Simon 

Well in that case, since you have two sets of hardware I would suggest running the TC in n-only mode as one wifi network and then attach the Extreme's WAN port to one of the TC's LAN ports. Set up the Extreme for a second wifi network but running g. Make sure to set the Extreme to bridged mode so that the TC handles all the DHCP/NAT stuff. Now all wifi clients can connect at their maximum speed and are still all part of the same LAN, IOW they can see and talk to each other.

I followed your instructions to omit the router in the basement and set up the Time Capsule as "main" base on the second floor (via patch panel). I could have left the TC in the basement but in the second floor office it will serve a usb-printer and also provides wifi out to the garage, which it didn't do in the basement (with a 16" thick stone wall between it and the garage). So this alone is a big improvement.

But I need to use the AEBS as a server for an iMac and a usb-printer in the basement. I can't run it directly (via ethernet) off the TC. So I need to set it up as an extension of the TC network. This itself is not problematic but it raises the prospect that this configuration will slow the whole network down to the 'g' speed of the AEBS.

The question here is can I set up the 'g' AEBS as a "relay" (or other) in a way that preserves the speed of the 'n' devices? If not, then I will need to plug in the new AEBS dual band. The question then is where best to plug it in. Perhaps I should put it where the TC is now, and put the TC where the AEBS-single band is now... ??

[Simon]

I'm afraid that's correct. Unless... You don't happen to have a second Ethernet connection from where the TC is to the basement patch panel, do you? You could connect that to one of the TC's LAN ports and then connect the AEBS to the patch panel in the basement.

If you set up the AEBS as WDS relay/remote in the basement, you will be looking at two issues. The first is you'll have to run the TC in g/n mixed mode (you'd still have to test how much of a throughput reduction this causes). The second is WDS. It's known neither to be especially stable nor to be very fast. Every WDS relay cuts theoretically available bandwidth to half of what it was upstream. You see this quickly leads to unacceptable speeds on a g network.

One way out would indeed be to use a hub or switch in the basement to split up the modem connection to the AEBS and the patch panel (for the TC) so that you can use the AEBS w/o WDS and w/o putting the TC in mixed mode. The problem with that solution is that clients on the TC will then no longer be on the same LAN as clients on the AEBS, added complexity if it's a switch (rather than a dumb hub), etc. Not such an awesome idea either.

If you can afford it, I think a new dual-band AEBS would be a better solution. You could set it up either in the basement or where the TC is now. Set it up for one n and one g network. Make sure the n devices connect to the n network. No WDS involved and no g device compatibility necessary on your n network.

To get a better price check the refurb section. The dual-band AEBS is $149 ($30 off) there.

[krx]

Originally Posted by Simon 

I'm afraid that's correct. Unless... You don't happen to have a second Ethernet connection from where the TC is to the basement patch panel, do you? You could connect that to one of the TC's LAN ports and then connect the AEBS to the patch panel in the basement.

Not an option unfortunately.

Originally Posted by Simon 

If you can afford it, I think a new dual-band AEBS would be a better solution. You could set it up either in the basement or where the TC is now. Set it up for one n and one g network. Make sure the n devices connect to the n network. No WDS involved and no g device compatibility necessary on your n network.

To get a better price check the refurb section. The dual-band AEBS is $149 ($30 off) there.

That's what I'll do - thanks for the link.

Originally Posted by Simon 

If you're interested in real-world throughput I suggest you try transferring large files and time the transfer. Also Activity Monitor > Network can also be useful as it shows you the actual current throughput.

What is it here that indicates throughput:

[Simon]

The green number is received data in B/s, the red is sent data in B/s.