Summary

Chapter 15: Advanced Networks 15Switches maintain a switching table. The switching table contains a list of all MACaddresses on the network and a list of which switch port can be used to reach a device witha given MAC address. The switching table records MAC addresses by inspecting the sourceMAC address of every incoming frame, as well as the port on which the frame arrives. Theswitch then creates a switching table that maps MAC addresses to outgoing ports. When aframe arrives that is destined for a particular MAC address, the switch uses the switchingtable to determine which port to use to reach the MAC address. The frame is forwardedfrom the port to the destination. When frames are sent from only one port to the destination,other ports are unaffected, and bandwidth on the entire network is unaffected.RoutersRouters connect networks. On a corporate network, one router port connects to the WANconnection, and the other ports connect to the corporate LANs. The router becomes thegateway, or path to the outside, for the LAN. In a home network, the router connects thecomputers and network devices in the home to the Internet. In this case, the router is ahome gateway. The wireless router, shown in Figure 15-3, serves as a firewall and provideswireless connectivity. When the home router provides multiple services, it may be called amultifunction device.Figure 15-3Home Networking DevicesISP EquipmentWhen subscribing to an ISP, you should find out what type of equipment is available so thatyou can select the most appropriate device. Many ISPs offer a discount on equipment that ispurchased at the time of installation.