Except for 802.11n-specific controls, the 600N's wireless settings will be familiar to anyone who has driven any other Linksys wireless router. Network Mode offers the options of Mixed, Wireless-A only or Wireless-G only (for the 5 GHz and 2.4 GHz radios, respectively) and Disable. The Radio Band control is where you can force use of 20 MHz or 40 MHz (channel bonded) wide channels.
Figure 12: Basic Wireless settings
The default settings of Auto put both radios into 40 MHz channel mode. This is ok for the 5 GHz radio, but is in violation of the Wi-Fi Alliance's 802.11n Draft 2.0 Certification process. The Alliance's Draft 2.0 Certification requirements call for "out of the box" operation in 2.4 GHz to default to using a legacy-friendly 20 MHz channel.
The Alliance would not comment for my previous story. I suppose I can't blame them, since the obvious hole in their Certification test process may have let through more products than just the 600N. I asked Linksys what they intend to do to bring the 600N into Draft 2 compliance and this was their response:
We will take the necessary steps to maintain our certification by following whatever procedures the WFA sets out if and when they update their test plan.
... which bounces the ball back to the Alliance.
This error gives Linksys a performance advantage in the 2.4 GHz band by defaulting to a 40 MHz channel, which provides higher bandwidth.
You would think that Linksys' competitors would be pressuring the Alliance to fix their process and require any vendor with non-conforming, but Certified, product to bring the product into compliance or risk losing their Certification. But if that is happening, it's not obvious.
Note that in order to set the Wide or Standard Channel, you must change the Radio Band from Auto. The Standard Channel setting is what you would think it is—the same as the channel setting for any 802.11a,b or g gear. But the Wide Channel is misleading and does not convey what the hardware is acutally doing.
The short story is that when a 40 MHz channel is used, the Extension channel is always 4 channels away from the Primary channel for 2.4 GHz radios. So, you can't really directly select the second, Extension, channel anyway and the Wide Channel setting is not needed. What's worse, however, is that the Wireless Status page uses the same misleading nomenclature, instead of reporting the actual channels in use.
Moving on to the Advanced settings, it's nice to see the AP Isolation, which keeps wireless clients from communicating with each other. So if you happen to forget to disable File and Printer sharing and have an open share, you won't get pwned.
Linksys' description of the Frame Burst control doesnt' shed much light on what it's actually doing. But if you are having trouble getting clients to connect or stay connected, you should try disabling it. The other controls on this page are pretty standard, so I won't go into them.
Figure 13: Advanced Wireless settings
Note that there is no transmit power control for either radio, nor is there a control to convert the 600N to function as an access point instead of a router. Finally, unlike the Apple Airport Extreme, the 600N doesn't support WDS bridging and repeating.