 the Ethernet switch and others of which are served by connecting shelves. On the backplane, you can provide internetworking between the Ethernet segments, so you can pro- vide internetworking on a campuswide basis. As the amount of traffic has grown in enterprises and as the nature of applica- tions has become more sophisticated, we have been increasing the bandwidth asso- ciated with LANs. Today, it is common to see 10Mbps being delivered to an individual desktop and 100Mbps serving as the cluster capacity. To facilitate inter- networking between these high-capacity desktops and Fast Ethernet clusters, Giga- bit Ethernet is increasingly being used in the backbone. As shown in Figure 6.3 earlier in the chapter, Gigabit Ethernet switches can connect underlying 100Mbps Ethernet Switch Switched Ethernet Connection Backplane Figure 6.9 An Ethernet switch LAN Interconnection and Internetworking or 10Mbps LAN segments, and the 10Mbps or 100Mbps LAN switches can deliver 10Mbps to the desktop and 100Mbps to the segment. VLANs Switched LANs enable us to create VLANs. A VLAN does not completely fit the earlier definition of a LAN as being limited in geographical scope; with a VLAN, geography has no meaning. A VLAN is a logically independent network, and mul- tiple VLANs can coexist on an individual physical switch. VLANs are used exten- sively in campus networks, allowing users to be part of the same broadcast domain while being physically separated, on different floors of a building, or in different buildings on a campus. This is because a VLAN is defined by software rather than by hardware and physical location. The major difference is that VLANs can restrict the broadcast and collision domain to members of a particular VLAN. Figure 6.10 shows an example of a VLAN. A switched VLAN is a high-speed, low-latency broadcast group that unites an arbitrary collection of endstations on multiple LAN segments. Switched virtual networking eliminates the bottlenecks normally associated with a physical LAN topology by creating high-