Internet protocol address preservation in mobile operator networks

A method of operating a mobile communications network arranged to communicate data packets between a mobile terminal and a packet data network via one or more routers, wherein the one or more routers include routing information for routing data packets, the method comprising establishing a data packet pathway for communicating data packets between a first Internet Protocol, IP, address associated with the mobile terminal and a second IP address associated with the packet data network, the data packet pathway including a first local gateway, wherein a local gateway is a first point within the mobile communications network through which all data packets communicated over the data packet pathway from the second IP address to the first IP address must pass; communicating one or more data packets between the first and second IP addresses via the data packet pathway; selecting a second local gateway; updating the routing information of at least one of the routers such that the second local gateway replaces the first local gateway in the data packet pathway; and communicating one or more data packets between the first and second IP addresses via the data packet pathway.