CCNA TechLab: Cisco Discovery Protocol (CDP)

In this TechLab, we will cover the Cisco Discovery Protocol (CDP) . CDP is a layer 2 protocol that is used for discovering information about neighboring network devices. Because CDP operates at the Data Link layer, it does not need a network layer protocol, such as IP or IPX, to transfer information. CDP devices send out periodic advertisements to the MAC multicast address 0100.0ccc.cccc, every 60 seconds by default.

CDP runs on all Cisco equipment such as routers, switches, bridges and access servers. It discovers information about neighboring devices such as the type of device and its capabilities, software version, the local and remote interface, and even configured network layer addresses. This information is stored in a table in the device’s RAM and is flushed on reboot.

Create the network

Connect 2 switches, 2 routers, and 1 PC as shown in the network diagram depicted above. Connect the serial cable so the router on the right becomes the DCE (not required, just remember which one is the DCE). The PC does not require any configuration and is optional.

Configure the routers and switches

Before we move on to CDP, we need to configure and enable the connections of the routers