It's pretty easy to build a fault-tolerant wireless network that lets users keep working despite component failures or power outages. By configuring a second Internet Authentication Service (IAS) server, you guarantee that wireless clients will still be able to connect even if your primary IAS server fails. Setting up a second IAS server is just a matter of installing IAS on a second server and using the Netsh command to copy the configuration from your first IAS server to the second. However, to get true redundancy for your wireless network, you'd need a second AP and at least two domain controllers (DCs) because IAS authenticates against credentials stored in AD. Your network switch would need a failover mate, and all of the APs, network switches, and servers would need UPS protection. With this equipment in place, if any component of your network fails or if you lose power, your laptop users will be able to continue working and accessing the network wirelessly.