Abstract: Telecommunication systems with packet-switched multimedia terminals and nodes for packet-switched multimedia sessions and with servers for exchanging multimedia signaling information for the packet-switched multimedia sessions and with terminating units are provided with gateways for in response to transferral messages originating from the packet-switched multimedia terminals and arriving at the servers transferring packet-switched multimedia sessions between packet-switched multimedia terminals and nodes to circuit-switched calls between gateways and circuit-switched terminals via switches, to continue possibly interrupted sessions via replacing calls. The servers send invitation messages to gateways, which send setup messages to switches for setting up circuit-switched calls via partly alternative communication paths. The servers send information messages to terminating units for bringing the terminating units from session level to call level.

Abstract: Telecommunication systems with packet-switched multimedia terminals and nodes for packet-switched multimedia sessions and with servers for exchanging multimedia signaling information for the packet-switched multimedia sessions and with terminating units are provided with gateways for in response to transferral messages originating from the packet-switched multimedia terminals and arriving at the servers transferring packet-switched multimedia sessions between packet-switched multimedia terminals and nodes to circuit-switched calls between gateways and circuit-switched terminals via switches, to continue possibly interrupted sessions via replacing calls. The servers send invitation messages to gateways, which send setup messages to switches for setting up circuit-switched calls via partly alternative communication paths. The servers send information messages to terminating units for bringing the terminating units from session level to call level.

Abstract: Telecommunication systems with packet-switched multimedia terminals (1) and nodes (8,9) for packet-switched multimedia sessions and with servers (2,3) for exchanging multimedia signaling information for the packet-switched multimedia sessions and with terminating units (4) are provided with gateways (7) for in response to transferral messages originating from the packet-switched multimedia terminals (1) and arriving at the servers (2,3) transferring packet-switched multimedia sessions between packet-switched multimedia terminals (1) and nodes (8,9) to circuit-switched calls between gateways (7) and circuit-switched terminals (5) via switches (6), to continue possibly interrupted sessions via replacing calls. The servers (2,3) send invitation messages to gateways (7), which send setup messages to switches (6) for setting up circuit-switched calls via partly alternative communication paths.

Abstract: Telecommunication systems with packet-switched multimedia terminals (1) and nodes (8,9) for packet-switched multimedia sessions and with servers (2,3) for exchanging multimedia signalling information for said packet-switched multimedia sessions and with terminating units (4) are provided with gateways (7) for in response to transferral messages originating from said packet-switched multimedia terminals (1) and arriving at said servers (2,3) transferring packet-switched multimedia sessions between packet-switched multimedia terminals (1) and nodes (8,9) to circuit-switched calls between gateways (7) and circuit-switched terminals (5) via switches (6), to continue possibly interrupted sessions via replacing calls. Said servers (2,3) send invitation messages to gateways (7), which send setup messages to switches (6) for setting up circuit-switched calls via partly alternative communication paths.