A secured network is disclosed configured to carry data, comprising a plurality of network bubbles and a plurality of network control points, wherein each network bubble comprises one or more bubble partitions and each bubble partition comprises at least one networked device configured to transmit and receive data, and all of the network devices corresponding to at least one of the plurality of network bubbles have a common network security policy. At least one network control point, such as a router, is provided with a marker module arranged to mark outgoing packets with a label corresponding to the network bubble from which the packets originate that can be used to enforce the network security policy of the at least one network bubble.