A hub is an older type of concentration device which also provides multiple ports. However, hubs are inferior to switches because all devices connected to a hub reside in the same bandwidth domain that produces collisions. Another drawback to using hubs is that they only operate in half-duplex mode. In half-duplex mode, the hubs can send or receive data at any given time, but not both at the same time. Switches can operate in full-duplex mode, which means they can send and receive data simultaneously.

Switches are multi-port bridges. Switches are the current standard technology for Ethernet LANs that utilize a star topology. A switch provides many dedicated, point-to-point virtual circuits between connected networking devices, so collisions are virtually impossible.

Because of their dominant role in modern networks, the ability to understand and configure switches is essential for network support.

A new switch will have a preset configuration with factory defaults. This configuration will rarely meet the needs of a network administator. Switches can be configured and managed from a command-line interface (CLI). Increasingly, networking devices can also be configured and managed using a web based interface and a browser.

A network administrator must be familiar with many tasks to be effective in managing a network with switches. Some of these tasks are associated with maintaining the switch and its Internetworking Operating System (IOS). Others are associated with managing interfaces and tables for optimal, reliable, and secure operation. Basic switch configuration, upgrading the IOS, and performing password recovery are essential network administrator skills.

Students completing this module should be able to:

• Identify the major components of a Catalyst switch
• Monitor switch activity and status using LED indicators
• Examine the switch bootup output using HyperTerminal
• Use the help features of the command line interface
• List the major switch command modes
• Verify the default settings of a Catalyst switch
• Set an IP address and default gateway for the switch to allow connection and management over a network
• View the switch settings with a Web browser
• Set interfaces for speed and duplex operation
• Examine and manage the switch MAC address table
• Configure port security
• Manage configuration files and IOS images
• Perform password recovery on a switch
• Upgrade the IOS of a switch