Dual Band Question

[BBurgDave]

Okay, there is something I still don't quite understand. I have read (here) that is it not a good idea to run mixed N and G clients on one radio as both take a hit. If I want to put 802.11G clients on one radio and 802.11N clients on another radio, can I accomplish this with a dual-band router such that the network clients on N and G can "see" each other? If I have a network printer, for example, connected on the G radio (running at 2.4Ghz) is it possible somehow for a laptop connected via 802.11N on the other radio to see that printer so that it can use it?

My impression is no since I think each radio needs to be configured with a different SSID, but I am still learning about this so maybe I am missing something.

 

[thiggins]

Yes, you should use a different SSID on the 2.4 and 5 GHz band radios if you want to be able to direct dual-band capable clients to a specific band.

Clients connected on each radio will be connected to the same wired network. (Think of each radio being connected to an internal port on the same switch where you plug in wired clients.)

So a G client would connect to the 2.4 GHz band radio and its data will flow to the wired LAN. The N client (if it is also dual-band) would connect to the 5 GHz band radio, which is also connected to the same wired LAN. So data can flow from radio to radio.

Note that you only have to worry about mixed G and N, if both client flavors are in heavy simultaneous use.

 

[BBurgDave]

Note that you only have to worry about mixed G and N, if both client flavors are in heavy simultaneous use.

Oh, that is a very interesting point. So if that is not the case, does that mean that even a single radio N router (e.g. DIR 655) will not really be impacted much by mixed mode issues? I was thinking that in general I needed to separate the N and G traffic on separate radios or I would take a hit ...

 

[thiggins]

See http://forums.smallnetbuilder.com/showthread.php?t=2506

 

[BBurgDave]

Okay - so if I read that correctly, I would probably be fine with a single radio in general, but if I think I will be using (at some point) N and G together a lot I would be better off with a dual band system with G dedicated to one radio and N to another.

BTW Tim, I have spent a lot of time reading material on your site and I find it very helpful - good job!

 

[thiggins]

Okay - so if I read that correctly, I would probably be fine with a single radio in general, but if I think I will be using (at some point) N and G together a lot I would be better off with a dual band system with G dedicated to one radio and N to another.

That only works if all your N clients are also dual band and can operate in the 5 GHz band. Dual band routers have one 2.4 GHz radio and one 5 GHz radio. You can't set one radio to handle G (2.4 GHz) and one to handle 2.4 GHz N.

BTW Tim, I have spent a lot of time reading material on your site and I find it very helpful - good job!

Thanks. Don't keep us a secret!

 

[BBurgDave]

That only works if all your N clients are also dual band and can operate in the 5 GHz band. Dual band routers have one 2.4 GHz radio and one 5 GHz radio. You can't set one radio to handle G (2.4 GHz) and one to handle 2.4 GHz N.

Yep, I understand that.

 

[kevinqian]

Tim, i've read this and the sticky and still seem a lil perplexed regarding mixed client operation. In the sticky, statement in bold seems to imply that even if the N and G clients are segregated, they will still interfere if both are transmitting simultaneously. Why?

Here's my situation:
I just bought the Netgear WNR3500 2.4ghz N router to replace the aging D-link DI-524 G router. Currently I have all wifi clients G/N connected to the WNR3500 in mixed mode. To get optimal performance, do you suggest I bring back the DI-524 from the dead and use that exclusively for G clients while the WNR3500 for N clients? Both are 2.4ghz only routers. So should I set the WNR3500 on ch.1 (20mhz) for N only and DI-524 on ch.11 for B/G? Would that work to fully optimize my wireless network? Also would it be possible to use 40mhz channels on the WNR3500 without interfering the DI-524?

Thanks!

 

[thiggins]

I clarified the sticky. The bold statement applies to the single-radio case.

You can get 40 MHz mode to work in 2.4 GHz if you set the channel to 1 or 11 on that router and set the G router to whichever of channel 1 / 11 you don't use. But you will be hogging bandwidth and being a bad wireless neighbor to neighboring WLANs.

 

[kevinqian]

I clarified the sticky. The bold statement applies to the single-radio case.

You can get 40 MHz mode to work in 2.4 GHz if you set the channel to 1 or 11 on that router and set the G router to whichever of channel 1 / 11 you don't use. But you will be hogging bandwidth and being a bad wireless neighbor to neighboring WLANs.

I live in the boonies and the next closest WLAN is barely traceable. So my original proposal of setting the N on ch. 1 and G on ch. 11 would optimize my wireless setup?

The only G client in my household is my iPhone which rarely gets used while im home. Is the performance decrease only applicable when G clients are actually connected and transmitting or is the mere setting of mixed mode N in the router setup detrimental to N performance.

 

[kevinqian]

I came across this article you wrote a while back that explains it in granular detail why mixed clients suck. I think you should link to this article in your sticky to for readers to make more sense of what you summarized in there. Coming straight into your sticky with no context was definitely a lil challenging.

http://www.smallnetbuilder.com/wire...224-add-dont-replace-when-upgrading-to-80211n

 

[thiggins]

Thanks for the suggestion. Link added to the sticky.