Abstract: Methods and related apparatus are described of operating a transaction proxy to act as a conduit for a structured transaction, such as Transaction Capabilities Application Part (TCAP) structured dialog between a first transaction peer, for instance an Short Message Service Center (SMSC), and a second transaction peer, for instance an Mobile Switching Center (MSC). The method comprises the steps of: receiving a begin message; determining an address of the first transaction peer from the begin message; responding to the begin message by sending a continue message to the first transaction peer; and, if no abort message is received from the first transaction peer, forwarding the begin message to the second transaction peer. Embodiments of the invention employ the techniques for filtering mobile terminating forward Short Message (mt-forwardSM) messages containing spoofed addresses in Global System for Mobile Communications (GSM) systems.

Abstract: A method of operating a gateway is disclosed to manage communications between a switched circuit network and an internet protocol network using a gateway. The method includes receiving at the gateway, a service call requesting the service for routing to an application server on the internet protocol network. If the application server is available the service call is routed to the first application server and the gateway generates an entry in its database. The entry includes the service identifier and the first application server identifier. If the application server is not available to accept the service call and the service call is routed to the application server when it is not available, the method includes sending a control message to the calling party on the switched circuit network.

Abstract: Methods and related apparatus are described of operating a transaction proxy to act as a conduit for a structured transaction, such as TCAP structured dialog between a first transaction peer, for instance an SMSC, and a second transaction peer, for instance an MSC. The method comprises the steps of: receiving a begin message; determining an address of the first transaction peer from the begin message; responding to the begin message by sending a continue message to the first transaction peer; and, if no abort message is received from the first transaction peer, forwarding the begin message to the second transaction peer.

Abstract: There is provided a method of coupling a switched circuit network and an internet protocol network. The switched circuit network and the internet protocol network are interconnected by a gateway. The gateway comprises a database. The switched circuit network comprises a service which is identified by a service identifier. The internet protocol network comprises a group of application servers and the group of application servers comprises at least one application server. Each of the at least one application server are identified by a specific application server identifier. The method comprises the step of generating an entry in the database in response to a service call requesting the service if the service call is routed to an available application server, wherein the service call is received from a calling party located on the switched circuit network, and wherein the available application server is comprised in the group of application servers.