Blog Cisco When and How to Use 20mhz vs 40mhz vs 80mhz When and How to Use 20mhz vs 40mhz vs 80mhz The word network is a simple word of seven letters, but is it that simple? Let's take a broader look to understand it rightly. If putting it simply, whenever we think of or talk about some inter-connected stuff or location, we refer it as a network.