2.2 WAN Devices
2.2.2 Routers and WAN switches
Routers are devices that implement the network service. They provide interfaces for a wide range of links and subnetworks at a wide range of speeds. Routers are active and intelligent network devices and thus can participate in managing the network. Routers manage networks by providing dynamic control over resources and supporting the tasks and goals for networks. These goals are connectivity, reliable performance, management control, and flexibility.

A WAN switch is a multiport networking device, which typically switches such traffic as Frame Relay, X.25, and Switched Multimegabit Data Service (SMDS). WAN switches typically operate at the data link layer of the OSI reference model. The Figure illustrates two routers at remote ends of a WAN that are connected by WAN switches. In this example, the switches filter, forward, and flood frames based on the destination address of each frame.
Case Study
  Washington Project: Deployment of Switches

As part of the Washington School District network design and implementation, you need to determine what type of switches to obtain, how many of them to obtain, and where to place them in the network. Possible locations include the MDFs and IDFs in the school locations and at the main district office. Additionally, you need to determine what types of switches are needed, such as LAN or WAN switches, and whether they need to be Layer 2 or Layer 3 switches. Finally, you need to determine the segmentation and security required to establish the types, number, and placement of switches in the network.