CDP Neighbor Discovery and Edge Suppression

Bundle lab · $29.99

Enable Cisco Discovery Protocol (CDP) on R1 to map directly-connected Cisco neighbors while suppressing CDP advertisements on the untrusted management-edge interface. Routers are directly cabled for true CDP adjacency and also share a common management LAN via SW1 alongside an Alpine MGMT host.

Learning objectives

• Explain why CDP only discovers directly connected Cisco devices
• Enable CDP globally and verify neighbor formation on point-to-point links
• Disable CDP advertisements on untrusted host-facing interfaces
• Use show cdp neighbors and show cdp neighbors detail to inventory adjacencies
• Differentiate discovery on the management LAN vs. router-to-router links

Troubleshooting focus

• No neighbors appear when CDP is disabled globally
• An interface shows no neighbors if it is administratively down or cabled incorrectly
• Seeing the switch as a neighbor on the management LAN but not other routers is expected (CDP is link-local)
• Host-facing ports should not advertise CDP; verify per-interface disablement