With the increase in popularity of laptops, it is very common for users to frequently reconnect to a previously visited network. In order to improve user experience in roaming scenarios, where the user connects back to a previously visited network where the user had a valid DHCP lease, DHCP network hint has been implemented in Windows 7 OS. DHCP network hint helps in identifying the correct DHCP configuration for a previously visited network and then using the configuration opportunistically. Network hint used in order to uniquely identify different network is SSID (Service Set Identifier) of a network.

Full Article