Handling resources in a communications network

A method and apparatus for managing Time Division Multiplex resources for a pool of Mobile Switching Center Servers in a communications network. Time Division Multiplex resources are provided at a Media Gateway function serving the pool of Mobile Switching Center Servers. Virtual Time Division Multiplex resources are allocated to each Mobile Switching Center Server in the pool and mapped to the Time Division Multiplex resources. An ISUP signalling proxy function may be provided at the Media Gateway function. TDM resources are allocated to at least one Mobile Switching Center, and associated with an identifier of the Mobile Switching Center Server. The TDM resources are mapped to the Time Division Multiplex resource identifier. When the media Gateway receives an ISUP message, it replaces the identifier with an ISDN User Part signalling proxy function identifier before sending the message to a node in an external network.