This invention relates to a method of handling a telephone call, and in particular to a method which allows long-distance telephone calls to be routed over the internet, to take advantage of the fact that this may be more cost effective for the telephone subscriber than relying on the normal telephone network.
WO96/20553 describes one possible communication system, in which the internet is used for an intermediate leg of a long-distance telephone call. Voice mail or facsimile messages can be sent to a subscriber, and will be stored at a dedicated node in the network, from which they may be retrieved by the subscriber. This document also describes an arrangement whereby one such subscriber may route a long-distance telephone call to another such subscriber, with the internet being used for an intermediate leg of the transmission, between the dedicated access nodes to which the two subscribers are connected.
However, this system requires that each subscriber should be registered with the network of dedicated access nodes, before the internet can be used to route a telephone call between them.
This invention relates to a method, and to a telephone exchange for use in such a method, which allows a telephone call to be routed over the internet, without requiring any specific registration by either of the subscribers. In preferred embodiments of the invention, when a calling subscriber indicates that he wishes a particular call to be routed over the internet, he is allocated an internet address for the duration of the call. His local telephone exchange determines which local exchange serves the called party, and establishes an internet connection thereto. The local exchange of the called party allocates an internet address to the called party for the duration of the call. This address is returned to the calling party""s exchange, thus allowing establishment of a connection over the internet for speech/data transfer between the calling and called parties.
Thus, the call can be routed over the internet without requiring either subscriber to have taken any special steps such as registering with a particular service provider, before the call is placed.
Moreover, the invention allows the call to be routed over the internet while using a desired telephone network protocol such as ISUP. This means that the use of the internet is transparent to the user, there is no feature of the call which appears different from a call which is routed over the normal telephone network. Moreover, the use of a telephone network protocol such as ISUP means that all services supported by ISUP, including IN services if available in the version of ISUP, are available even though the call is routed over the internet.