A network of nodes transports a plurality of flows from central nodes to a plurality of display sessions executing processes that operate under the control of one or more central operating systems. A plurality of isolated virtual nodes comprises 1) a plurality of virtual graphics nodes that concurrently process graphics flows used in the plurality of display sessions at the plurality of remote zero client nodes and 2) a plurality of virtual switches that switch the concurrently processed graphic flows from the virtual graphics nodes to the plurality of remote zero client nodes. Two or more graphic flows are used simultaneously in two or more display sessions at a single remote zero client node that executes a separating operating system for separating the two or more display sessions from each other based on a a separation policy for the two or more graphics flows.