X.25 specifies an interface between a host system and a packet-switching network. Packet level - provides a virtual circuit service that enables any subscriber to the network to set up logical connections called virtual circuits, to other subscribers. Usually connotes government control or national monopoly. Wide Area Telecommunications services use circuit switching. Bursty traffic - short, sporadic transmissions.
Packet switching is best for bursty traffic.
Strategic control - designing and implementing the network to meet the organization's unique requirements. Possible with dedicated lines of private packet-switching network. Growth control - allows users to plan for network expansion and modifications arising as their needs change. Private packet-switching networks allows this.