Establishing bi-directional communication sessions across a communications network

On receipt of a request for a communication session over a communications network, such as an Internet Protocol communications network, a path for the session is established. In a preferred example the communications network is an MPLS network and the method uses a modified version of the SIP messaging protocol. Bandwidth along a chosen path is reserved and a messaging protocol such as CR-LDP used to establish this reserved path for the communication session. Internet protocol and MPLS communications networks typically only support uni-directional flows. Several methods for establishing bi-directional communication sessions over internet protocol communications networks that use MPLS connections are described. This is particularly useful for telephony applications using internet protocol communications networks. In a preferred example, the established connection provides a guaranteed level of quality of service.