Introduction

Chapter 2 is concerned with wide area network (WAN) technologies and topologies. A WAN connects other networks, or groups of networks separated geographically or by organizational design. Unlike a local area network (LAN), a WAN does not concern itself with providing direct connectivity to end devices such as workstations, servers, and printers. It provides the means for the networks on which those devices reside to reach remote destinations.

When it comes to networking, hard and fast rules tend to be broken. A WAN can be configured to provide connectivity to any of the end devices previously described; a single server at a distant location can be connected via a WAN to the rest of the organizational network.

This chapter gives an overview of WAN technologies provided by Cisco, including their features and salient points. It also provides configuration details for deployment and support of WANs, especially on routers.

When analyzing the traffic requirements between remote offices and your central site, you may find it is not cost-effective to use ad hoc "dial connection" connection. Under these circumstances, you need to implement a permanent connection. This chapter explores several ways of providing permanent connections: point-to-point links of all types such as High-Level Data Link Control (HDLC), Point-to-Point Protocol (PPP), and the various varieties of T1. Frame Relay and Asynchronous Transfer Mode (ATM) also figure predominantly in this chapter.

Frame Relay is a common method used to connect a WAN; ATM is also commonly used for WAN connections. This chapter covers...