The main contents of this chapter include all of the following: Wide-Area Network, WAN Access and the OSI reference model, WAN devices, physical layer: WANs, serial Point-to-Point connections, WAN-Multiple LANs,. Inviting you to refer. | WAN Connections Understanding WAN Technologies Wide-Area Network Need for WANs WANs vs. LANs WAN Access and the OSI Reference Model WAN Devices Routers Terminal servers Modems DSU/CSU WAN networking devices ATM switches Frame Relay switches PSTN Physical Layer: WANs Serial Point-to-Point Connections Purpose: This section describes the various serial standards that support leased-line connections. Emphasize: The same 60-pin end that attaches to a Cisco device supports all the standards illustrated. Note: Data switching equipment (DSE) is an additional term sometimes used to describe the switch components that appear inside the cloud. The DSE adds and removes channels assigned inside the WAN. The DSE connects traffic from various sources to their final destinations through other switches. Transition: The next layer in the stack is Layer 2, the data link layer. WAN—Multiple LANs WAN Data-Link Protocols HDLC PPP Frame Relay (LAPF) ATM WAN Link Options Circuit Switching Public Switched Telephone Network PSTN Considerations Advantages Simplicity Availability Cost Disadvantages Low data rates Relatively long connection setup time Leased Line WAN Connection Bandwidth Configuring a Serial Interface Enter global configuration mode. RouterX(config-if)#clock rate 64000 RouterX(config-if)# RouterX(config)#interface serial 0/0/0 RouterX(config-if)# RouterX#configure terminal RouterX(config)# RouterX(config-if)#bandwidth 64 RouterX(config-if)#exit RouterX(config)#exit RouterX# Specify interface. Set clock rate (on DCE interfaces only). Set bandwidth (recommended). Serial Interface show controller Command Shows the serial cable type | WAN Connections Understanding WAN Technologies Wide-Area Network Need for WANs WANs vs. LANs WAN Access and the OSI Reference Model WAN Devices Routers Terminal servers Modems DSU/CSU WAN networking devices ATM switches Frame Relay switches PSTN Physical Layer: WANs Serial Point-to-Point Connections Purpose: This section describes the various serial standards that support leased-line connections. Emphasize: The same 60-pin end that attaches to a Cisco device supports all the standards illustrated. Note: Data switching equipment (DSE) is an additional term sometimes used to describe the switch components that appear inside the cloud. The DSE adds and removes channels assigned inside the WAN. The DSE connects traffic from various sources to their final destinations through other switches. Transition: The next layer in the stack is Layer 2, the data link layer. WAN—Multiple LANs WAN Data-Link Protocols HDLC PPP Frame Relay (LAPF) ATM WAN Link Options Circuit Switching Public Switched Telephone Network PSTN Considerations Advantages Simplicity Availability Cost Disadvantages Low data rates Relatively long connection setup time Leased Line WAN Connection Bandwidth Configuring a Serial Interface Enter global configuration mode. RouterX(config-if)#clock rate 64000 RouterX(config-if)# RouterX(config)#interface serial 0/0/0 RouterX(config-if)# RouterX#configure terminal RouterX(config)# RouterX(config-if)#bandwidth 64 RouterX(config-if)#exit RouterX(config)#exit RouterX# Specify interface. Set clock rate (on DCE interfaces only). Set bandwidth (recommended). Serial Interface show controller Command Shows the serial cable .
