A communication apparatus, which is connected to an external apparatus via a network, comprising first and second data communication units, wherein when the first data communication unit establishes a connection to an external apparatus via a network formed by a relay apparatus, the apparatus participates in the network formed by the relay apparatus, and when the second data communication unit, which forms a network in which the communication apparatus serves as a relay apparatus, establishes a connection to the external apparatus, the apparatus forms the network in which the communication apparatus serves as a relay apparatus using parameters of the network stored when the connection to that external apparatus is established.