In a Virtual Circuit network, also called a Connection Network, the sender first attempts to create a "virtual circuit" to the receiver. If successful the communication is assigned a virtual circuit number in each of the participating nodes and then each packet's address is just this virtual circuit data. Unlike a real circuit switch exchange there is no resource, other than some space reserved in circuit tables, that is reserved for the duration of the communication. Note: the terms``sender'' and ``receiver'' apply only to the process of establishing the virtual circuit; once set up, data can flow in either direction. An analogy is a phone network. Dialing the number sets up the call establishing a circuit through all intervening phone exchanges. After that all data passes over this circuit.