I found a great article by Michael Horowitz.
“The Guest networks offered by most routers are a nice security feature. By keeping visitors away from the main network (both wired and wireless), they allow for the safe sharing of Internet access without divulging the private Wi-Fi password.
Up till now, the Guest networks I had run across, in consumer routers, all worked basically the same, although some routers offer far more control over them than others. Guest networks are defined just like the private Wi-Fi network(s) but with their own name (SSID), encryption (WEP, WPA or WPA2) and password.”
Read Full Article Here for author credit