Summary

Cisco Catalyst LAN switches possess many features that make them much more than just a "dumb" Layer 2 switch. All Catalyst switches offer a rich operating system interface that enables you to perform advanced maintenance, monitoring, and troubleshooting tasks. In terms of maintenance, Catalyst switches are easy to upgrade, allowing you to protect your investment by adding new features to your existing switches as they become available. Flexible backup mechanisms allow you to store configuration files and image files at a remote network location using TFTP; you can also use TFTP to restore files as you want. All backup, restore, and upgrade operations can be performed across the network, reducing the administrative overhead of these tasks and allowing switches to be maintained remotely. You learned about common troubleshooting issues within LAN networks and how you can identify and resolve these issues. Common issues include port startup delays, which can cause a workstation to not have network connectivity when it first boots. Another common issue on CatOS-based switches is the errDisable port state, which means that the switch has shut down the port in response to some error condition. A variety of reasons why the errDisable state is invoked exist, and you learned how to identify and resolve them.

The ability to capture traffic within a switched network is also important. Traditionally, in hub-based networks, traffic capture has simply been a process of attaching to a hub port and because of the shared nature of hubs, all traffic can be captured. Switches are designed for efficiency and send only unicast traffic out the ports upon which destination systems are located. This makes it much more difficult to capture traffic in a switched environment. Cisco provides SPAN, RSPAN, and VLAN ACLs as mechanisms by which you can capture traffic on a switch.