Network Sales and Services Handbook (Cisco Press Networking Technology)

Four basic types of networking hardware are used in an internetwork:

• Hubs (LAN) Hubs connect multiple LAN hosts and users to a single device, which in turn is connected to the network.

• Bridges (LAN) Bridges logically separate network segments within the same network and operate at the Data-Link layer of the OSI Reference Model.

• Switches (LAN/WAN) Similar to bridges, switches provide a unique network segment on each switch port, separating LAN collision domains (in turn minimizing LAN congestion).

• Routers (LAN/WAN) Routers interconnect different networks and separate broadcast domains. Routers are protocol-dependant and operate at the Network layer of the OSI Reference Model.

Each of these network devices performs internetworking functions in accordance with their location within the hierarchical network model, not to be confused with their geographic location within the network.