Abstract: A method of controlling a user device in a telecommunications network having a first part and a second, different part is provided. The method includes, at the user device, receiving a first communication session setup request to set up a given communication session, the first communication session setup request being directed to a first communication interface, receiving a communication notification in relation to the same given communication session, the communication notification being directed to a second communication interface, establishing the given communication session via the first communication interface via the first part of the telecommunications network, and after having established the given communication session via the first communication interface, activating an alert function to alert a user of the user device to the availability of the second communication interface at least on the basis of having received the communication availability notification.

Abstract: A method of controlling a communication session is provided. The communication session is established in a telecommunications network between a first communication client of a plurality of communication clients on one or more communication devices associated with a first party and a communication device associated with a second party, the established communication session comprising at least a first communication session leg established between the first communication client and an intermediate node in the telecommunications network. The method includes detecting a loss in connectivity associated with the first communication session leg, and in response to detecting the loss in connectivity, initiating set up of a second communication session leg between an intermediate node in the telecommunications network and at least a second communication client of the plurality of communication clients on one or more communication devices associated with the first party.

Abstract: A method of initiating a voice call via a dialler user interface on a user device in a telecommunications network is provided. The user device comprises at least a first communication client adapted to communicate via a first part of the telecommunications network and a second communication client adapted to communicate via a second, different part of the telecommunications network. The method includes, at the user device, receiving, via the dialler user interface of the user device, user input from a user of the device associated with initiating setup of a communication session, and selecting a given one of the first and second communication clients to pass the user input to for processing, whereby a communication session setup request is transmitted from the given communication client into the respective part of the telecommunications network.

Abstract: A method of providing failover processing between a first element and a second element in a data communications network, the method comprising configuring a first channel and a second channel between the first and second elements, the first and second channels comprising different physical data paths, receiving at the first element, via the first channel, first data signals representative of functioning statuses of the second element, the first channel being configured to allow a non-optimal, partly functioning status of the second element to be communicated to the first element; and receiving at the first element, via the second channel, second data signals representative of functioning statuses of the second element, the second channel being configured to allow a failed functioning status of the second element to be communicated to the first element; and conducting failover processing based on both the first and second data signals.

Abstract: Methods, apparatus and computer program products for indicating availability in a telecommunications network are provided. An availability alerting service is initiated in response to a trigger associated with non-completion of an initial call from a calling party to a called party, the availability alerting service provides the calling party with availability alert information to solicit a follow-up call from the calling party when the called party has a given availability state after the initial call. The availability alerting service detects a first availability status change after initiation of the alerting service, and transmits a first availability update message to the calling party to solicit the follow-up call. A second availability status change is detected, subsequent to the first availability status change, and a second availability update message is transmitted to the calling party to inhibit the follow-up call.

Abstract: A method of processing Session Initiation Protocol (SIP) signalling messages in a telecommunications network is provided. The method includes, at a SIP routing element, maintaining a routing database containing routing data for routing SIP signalling messages between SIP network elements, maintaining a group of simultaneously active modes including at least a SIP proxy server stateless mode and a SIP proxy server stateful mode, receiving a plurality of SIP signalling messages from SIP network elements, routing at least some of the received SIP signalling messages with reference to the routing database according to a SIP proxy server stateless mode, and routing at least some of the received messages with reference to the routing database according to a SIP proxy server stateful mode.

Abstract: Measures for use in processing communication sessions in a telecommunications network are provided. Each communication session has a signalling path spanning a plurality of devices including one or more intermediate network devices and at least two endpoint devices, the signalling path comprising a plurality of signalling segments, each segment being between two devices in the plurality of devices. A first signalling message, comprising a first identifier associated with the communication session, is received via a first signalling segment for a communication session. At least part of the first identifier is transformed using a deterministic encryption algorithm to generate a second identifier. A second signalling message, comprising the second identifier, is transmitted via a second signalling segment for the communication session to associate the second identifier with the communication session.

Abstract: A finite state machine is provided. The finite state machine causes a function to be carried out in dependence on at least an event input to the finite state machine and the current state of the finite state machine. Associations between the functions that are to be carried out and combinations of the states and the events are identified using an associative array. The associations identified using the associative array are amended while the finite state machine is operating to dynamically reconfigure the operation of the finite state machine.