US Patent 9807040 Instant messaging system and method

An instant messaging system comprising an instant messaging server to which a plurality of client devices are connectable to the Internet; where client device(s) belonging to a user is connectable to the instant messaging server by using an identifier of the user; wherein in a default mode an instant message is sent from a client device to the instant messaging server for routing to an intended recipient via Internet connection; and if the Internet connection is not available the instant message is routed via another electronic link to the instant messaging server for routing to an intended recipient, the another electronic link using a session-based protocol is disclosed.