© 2007 Cisco Systems, Inc. All rights reserved.ICND1 v1.0—2-1 Module Summary  Ethernet cables and segments can span only a limited physical distance, but there are devices, such as repeaters and hubs, that can be added to an Ethernet LAN to extend segments.  Bridges and switches divide a LAN into multiple segments. However, switches operate at much higher speeds and support more advanced functionality, performing three major functions in segmenting an Ethernet network: forwarding, filtering, and flooding.  There are a number of ways in which the performance benefits of switched Ethernet LANs can be enhanced, including microsegmentation and connectivity hierarchies; however, there is the potential for intentional or unintentional physical loops that can be solved by STP.

© 2007 Cisco Systems, Inc. All rights reserved.ICND1 v1.0—2-2 Module Summary (Cont.)  The Cisco IOS CLI is used to communicate the configuration details that implement the network requirements of an organization.  The startup of a Cisco Catalyst switch requires verifying the physical installation, powering up the switch, and viewing the Cisco IOS Software output on the console.  The CLI is used to configure the switch name and passwords and to enter console commands such as router interfaces and IP addresses.  Increase switch security by enabling password and port security  Most port access problems can be verified using the show interface command.

© 2007 Cisco Systems, Inc. All rights reserved.ICND1 v1.0—2-3