CCNA Discovery 2, Chapter 5

5.5.3: Telecommunications service providers (TSP) typically maintain a network over large geographic areas. A TSP can provide the following WAN connections to individuals and organizations:

• A point-to-point (PPP) connection provides a specific dedicated path through the TSP network to connect two LANs over a large geographic area.

• A circuit-switched WAN connection allows the client to create and close connections over the TSP network; this connection operates like a phone call. Integrated services digital network (ISDN) is an example of a circuit-switched connection.

• A packet-switched WAN connection allows multiple clients to share a single connection. Unlike a circuit-switched network, in which the client temporarily uses the entire connection, a client on a packet-switched network uses a virtual circuit (managed by software) over a shared connection. Frame Relay is an example of a packet-switched connection.