Ccna routing and Switching Complete Study Guide

WAN Connection Types

You’re probably aware that a WAN can use a number of different connection types avail-

able on the market today. Figure 21.5 shows the different WAN connection types that can be 

used to connect your LANs (made up of data terminal equipment, or DTE) together over 

the data communication equipment (DCE) network.

f i g u r e   21. 5     WAN connection types

Dedicated

Circuit-switched

Packet-switched

Telephone

company

Service

provider

Synchronous serial

Asynchronous serial, ISDN

Synchronous serial

Let me explain the different WAN connection types in detail now:

Dedicated (leased lines)    These are usually referred to as a point-to-point or dedicated 

connections. A leased line is a pre-established WAN communications path that goes from 

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Chapter 21 

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  Wide Area Networks

the CPE through the DCE switch, then over to the CPE of the remote site. The CPE enables 

DTE networks to communicate at any time with no cumbersome setup procedures to mud-

dle through before transmitting data. When you’ve got plenty of cash, this is definitely the 

way to go because it uses synchronous serial lines up to 45 Mbps. HDLC and PPP encapsu-

lations are frequently used on leased lines, and I’ll go over these with you soon.