Establishing connection across a connection-oriented first telecommunications network in response to a connection request from a second telecommunications network

A first Multi Protocol Label Switching (MPLS) Internet Protocol (IP) data network transmits data to a second MPLS IP network via a legacy network, which would not otherwise be able to handle the required user network interface (UNI) protocol by configuring the legacy network and its connection computing apparatus (CCA) so that they emulate an MPLS network. When a firt network element (NE) receives a connection (UNI) request from the MPLS network under a UNI protocol, the UNI request is passed to the CCA, which then sets the required connection across the legacy network via a second network element (NE) to an NE of the second network. Once the connection has been set, the CCA instructs the NE to send a return signal to the requesting network indicating that the connection has been successfully set. Data packets may then be transmitted across the network.