Differential latency measurement

A method of selecting an optimal communication routing between a user equipment, UE, device and a core network wherein a plurality of differing radio communication paths are establishable between the UE device and the core network, the method comprising:

• in a state where only a first radio communication path is established between the UE device and the core network, determining at a first one of the UE device and a core network entity that a communication path latency measurement shall be performed and informing the other one of the UE device and the core network entity that the communication path latency measurement will be performed;
• establishing at least a second radio communication path between the UE device and the core network;
• transmitting over at least the first radio communication path and the second radio communication path duplicate data packets;
• determining from the data packets received over the first and the second radio communication paths a latency difference measurement between transmission over the first radio communication path and the second radio communication path;
• using the latency difference measurement choosing the radio communication routing from the first radio communication path and the second radio communication path for subsequent communication.