| Overview

Sometimes network administrators are faced with situations where network documentation is incomplete or inaccurate. Cisco Discovery Protocol (CDP) can be a useful tool in these situations because it can help to build a basic picture of the network. CDP is a media and protocol independent, Cisco proprietary protocol used for neighbor discovery. CDP will only show information about directly connected neighbors but it is nevertheless a powerful tool. In many cases after a router is initially configured it is difficult or inconvenient for a network administrator to connect directly to the router for configuration changes or other activities. Telnet is a TCP/IP-based application that allows remote connection to the router command-line interface (CLI) for configuration, monitoring, and troubleshooting purposes. It is an essential tool for the network professional. Students completing this module should be able to: Enable and disable CDP Use the show cdp neighbors command Determine which neighboring devices are connected to which local interfaces Gather network address information about neighboring devices using CDP Establish a Telnet connection Verify a Telnet connection Disconnect from a Telnet session Suspend a Telnet session Perform alternative connectivity tests Troubleshoot remote terminal connections