Patent ID: 8787760

Claim:
A server device configured to provide a service to a client device, the server device comprising: an information management unit that stores and manages a plurality of types of connection information which have different importance levels, respectively, in association with the respective importance levels, the connection information being necessary for connection to a service provided by the server device; an optical signal transmission unit that modulates the plurality of types of connection information stored in the information management unit into optical signals, such that a type of connection information stored in association with a higher importance level has a smaller amount of change in light intensity, and repeatedly transmits the optical signals having the plurality of types of connection information, respectively, by use of a first communication function; and a service provision unit that has an authentication function which performs authentication when the client device has issued a connection request containing a predetermined type of connection information among the plurality of types of connection information by use of a second communication function which is different from the first communication function, in accordance with the importance level of communication information of the connection request, the authentication being for providing the service to the client device.