How to know if my network is 2.4 GHz or 5 GHz?

If you have a Mac, hold down the option key while you click on the AirPort icon at the top of the screen.

Look for the Channel setting

That will tell you what channel you are on and whether you are connected to 2.4 GHz or 5 GHz at the present time.

5 GHz connections are usually faster connections than 2.4 GHz. If your Mac is located a few rooms away from the wireless router, it will probably connect to 2.4 GHz since those signals will be stronger.

If you are close to the Cisco router and you are picking up 2.4 GHz then that is likely all that the Cisco device is capable of producing. If you have a model number handy, we can check.

A new router will produce both a 2.4 GHz and 5 GHz network simultaneously. Wireless devices will automatically connect to the better quality signal based on their location in relation to the wireless router.

I cannot say whether you would notice any significant improvement with a new router.

That is where Apple's 14 day return privilege may come in handy. The bottom line with any wireless setup is that you will not know how well it performs in your home...until you actually try it out in your home.

The 3rd through current generation of the AirPort Extreme base stations are simultaneous dual-band (2.4 & 5 GHz) wireless routers. Only the first two generations were single band (either 2.4 or 5 GHz, but not both simultaneously.)

Neither of the models listed are simultaneous dual band products.

They can produce either a 2.4 GHz network....or......a 5 GHz network....but not both simultaneously.

I’m planning to connect an Airport Express unit or the Extreme N to act as extenders (in addition to my current Linksys router or a new Extreme that I might get) to make sure the Wi-Fi signal is strong throughout my house. In this case, does having simultaneous dual bands even matter? OR is it still something I want even with good Wi-Fi signal coverage?

To get an idea on how a simultaneous dual-band router can extend both bands at the same time please take a glance at the following image. Note that both base stations must be within range for both bands to extend both. In the image only the 2.4 GHz band would be extended. However there would still be network connectivity.

Airport Extreme doesn't have 2 GHz and 5 GHz simultaneously? I can produce both with Airport Express

Airport Extreme doesn't have 2 GHz and 5 GHz simultaneously?

We already explained this once before. Please review a few posts back.

The question was about an A1143 version of the AirPort Extreme.

We said that this version could produce either a 2.4 GHz.....or......a 5 GHz signal, but not both simultaneously.

If you are asking about a different version of the AirPort Extreme......a 3rd Generation or higher model......those versions would all be capable of simultaneous dual band operation