The eduroam service involves infrastructure to remotely authenticate users, i.e. to send the network access authentication request from the institution they're visiting back to their home institution.
In order to use eduroam, the user needs to initially configure their mobile device(s) to perform eduroam authentication when connecting to the "eduroam" SSID at their home institution. The "eduroam network" should be configured for automatic connection. Home institutions provide instructions for users to configure their mobile devices on their local eduroam webpage.
Then, when the user visits an eduroam service provider organisation which broadcasts the "eduroam" SSID, their device(s) will automatically connect to the visited institution's eduroam network, resulting in a remote authentication request to the user’s home institution, and if successful access is granted to the visited institution’s network.
Service provider organisations are encouraged to make the eduroam network as open as possible, so visitors are likely to be able to access the same set of network services as they would if they connected to the network on their home institution campus. As well as internet access via HTTP, users should be able to connect to their home institution's network via VPN and access their computer resources at their home institution.