ches are a very cost-effective solution to the need for increased bandwidth in workgroups. Each port on the switch delivers a dedicated channel to the device or devices attached to that port, thereby increasing the workgroup's total band- width and also the bandwidth available to individual users. Figure 6.8 shows a simple example of a switched Ethernet configuration. One workstation requires 100Mbps on its own, SO it has the full services of a 100Mbps port on the switched Ethernet card. Five workstations, on the other hand, each need 20Mbps, SO one 100Mbps port serves all five workstations. These five work- stations connect into a hub, and that hub connects into the actual port. (Today such configurations are largely managed by the local switches.) Servers have extra bandwidth requirements-th ones in Figure 6.8 require 200Mbps-so they are each served by a bonding of several 100Mbps ports. The key applications for LAN switches are to interconnect the elements of a dis- tributed computing system, to provide high-speed connections to campus backbones Ethernet Switch 100Mbps 20Mbps 20Mbps 100Mbps Figure 6.8 An example of a switched Ethernet configuration Chapter 6 Local Area Networking and servers, and to provide high bandwidth to individual users who need it. Instead of sharing a 10Mbps or 100Mbps LAN among a number of terminals in a workgroup, a LAN switch can be used, and an individual workstation can get the entire 10Mbps or 100Mbps. LAN switches provide great scalability because they enable the network to increase in bandwidth with the fairly simple addition of more switched ports. In addition, switches operate in full-duplex mode and as such use dedicated outgoing and incoming channels to allow full-speed transmission in both directions at the same time. Thus, LAN switches have many benefits, including scalability in terms of bandwidth, flexibility, and high performance. Figure 6.9 shows how an Ethernet switch can be used to connect devices that are on the same segment, some of which are served by one shelf of