> | Lab 4.3.5 CDP neighbors Estimated time: 30 min. Objectives: Use CDP commands to get information about neighboring networks and routers. Display information on how CDP is configured for its advertisement and discovery frame transmission. Display CDP updates received on the local router. Background: In this lab you will use the show cdp command. Cisco Discovery Protocol (CDP) discovers and shows information about directly connected Cisco devices (routers and switches). CDP is a Cisco proprietary protocol that runs at the data link layer (layer 2) of the OSI model. This allows devices that may be running different network layer 3 protocols such as IP or IPX to learn about each other. CDP begins automatically upon a device's system startup, however if you are using Cisco IOS Release 10.3 or newer version of IOS you must enable it on each of the device's interfaces by using the cdp enable command. Using the command show cdp interface you will gather information CDP uses for its advertisement and discovery frame transmission. Use show cdp neighbors and show cdp neighbors detail to display the CDP updates received on the local router. Tools / Preparation: Prior to starting the lab you will need to connect a PC w/ HyperTerminal to a router using the router's console Interface with a roll-over cable. Work individually or in teams. Before beginning this lab you may want to read the Networking Academy First Year Companion Guide, Chapter 13. You should also review On-line Chapter 4. Be familiar with the following show commands: show interface show cdp show cdp interface show cdp neighbors show cdp neighbors detail Resources Required: PC with Windows operating system and HyperTerminal installed Router connected to the PC with a console roll-over cable At least 3 routers interconnected via Ethernet or WAN simulation cables Websites Sites Resources: Routing basics General information on routers 2500 series routers 1600 series routers Terms and acronyms IP routing protocol IOS command summary Beginning IP for new users Notes: Step 1 - Log on to router. Explanation: Connect to the router and login. Enter the password cisco if prompted. Step 2 - Gather information about the router you logged into by issuing the show interface command. Task: Enter show interface command at the router prompt. Explanation: The router shows information about the configured interfaces. 1. Document the following information about the router: a. What is the name of the router? b. List IP address and subnet mask of the interfaces.
> Interface | IP Address | Subnet mask
> c. List operational status of each interface.
> Interface | Interface Up or Down? (Carrier Detect Signal) | Line Protocol Up/Down? (Keep Alives Being received)
> Step 3 - Display the values of the CDP timers, the interface status, and encapsulation used. Task: Enter show cdp interface command at the router prompt. Explanation: The router responds with CDP information on all interfaces that have CDP enabled. Global CDP settings can be seen using the show cdp command by itself. 2. How often is the router sending CDP packets? 3. What is the holdtime value? Step 4 - Display the CDP updates received on the local router. Task: Enter show cdp neighbors command at the router prompt. Explanation: The router will respond with information about its neighbors that have CDP enabled. 4. Fill in the following table:
> Device and Port ID | Local Interface | Hold Time | Capability | Platform
> Step 5 - Display details about CDP updates received on the local router. Task: Enter show cdp neighbors detail from the router prompt. Explanation: The router will display the entry address(es), IOS version, and the same information as the show cdp neighbors command. 5. Fill in the following table:
> Neighbor device name |  |  |
> Neighbor device type |  |  |
> IP address of interface attached to your router |  |  |
> Port ID of your router that the neighbor is on |  |  |
> Port ID of neighbor router that your router is on |  |  |
> IOS version of neighbor router |  |  |
> Step 6 – Telnet to your neighbor router and issue show cdp neighbor. Task: a. Telnet to neighboring router by entering telnet (hostname of router or IP address). b. Enter the password cisco. c. Enter show cdp neighbor at the router prompt you have telneted to. Explanation: The router will respond with information about its neighbors that have CDP enabled. NOTE: Perform this step at router lab-b, lab-c, or lab-d and telnet to your two neighbors on either side. 6. Fill in the following tables: First neighbor
> Device and Port ID | Local Interface | Hold Time | Capability | Platform
> Second neighbor
> Device and Port ID | Local Interface | Hold Time | Capability | Platform