show cdp neighbors detail is a Cisco IOS EXEC command for inspecting the detailed CDP information learned from directly connected neighbors. It reveals neighbor identity, hardware platform, capabilities, local and remote ports, holdtime, software version, VLAN, duplex, and CDP version. section 1.1.1 section 1.3
Interpret the most exam-relevant fields carefully:
- Interface identifies the local device’s port; Port ID (outgoing port) identifies the neighbor’s port. section 1.1.1
- Use show cdp entry name to display equivalent detail for one named neighbor instead of all neighbors. section 1.1.1
- CDP runs on Cisco devices and is enabled globally and on interfaces by default. section 1.3
Typical verification
R1# show cdp neighbors detail displays Device ID SW1, platform WS-C2960C, Router Switch IGMP capabilities, local interface GigabitEthernet0/0, neighbor port GigabitEthernet0/1, holdtime, IOS version, native VLAN, duplex, and total entries. section 1.1.1
R1# show cdp neighbors detail
-------------------------
Device ID: SW1 #1
Entry address(es):
Platform: cisco WS-C2960C-8PC-L, #2
Capabilities: Router Switch IGMP #2
Interface: GigabitEthernet0/0, #3
Port ID (outgoing port): GigabitEthernet0/1 #3
Holdtime : 170 sec #4
Version :
Cisco IOS Software, C2960C Software (C2960c405-UNIVERSALK9-M),
Version 15.0(2)SE5, RELEASE SOFTWARE (fc1)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2013 by Cisco Systems, Inc.
Compiled Fri 25-Oct-13 14:35 by prod_rel_team
advertisement version: 2
VTP Management Domain: ''
Native VLAN: 1
Duplex: full
Total cdp entries displayed : 1
#1 The neighbor’s hostname
#2 The neighbor’s hardware model and capabilities
#3 Interface lists the local device’s (R1’s) port, and Port ID lists neighbor’s (SW1’s) port.
#4 The current holdtime; 10 seconds have elapsed since R1 received an advertisement from SW1.
Browse the annotated detailed output to connect each displayed field with its operational meaning. section 1.1.1
