======CDP and LLDP======

[[https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst9300/software/release/17-18/configuration_guide/nmgmt/b_1718_nmgmt_9300_cg/configuring_the_cisco_discovery_protocol.html|Configuring CDP IOS-XE version 17.18]]\\ 

  * No difference between any 17.9 - 17.18 versions

[[https://www.youtube.com/watch?v=hrQff3fTViY|Charles Judd - Layer 2 Protocols]]\\ 

=====CDP=====

Cisco Discovery Protocol
  * v2 enabled by default
  * Hello time = 60s
  * Hold time = 180s
  * Cisco proprietary
  * CDP messages are sent in clear text

====Configuration====

  * Set timer
    * <code>sw(config)#cdp timer 80</code>
  * Set hold time
    * <code>sw(config)#cdp holdtime 240</code>
  * Set to CDP v2
    * <code>sw(config)#cdp advertise-v2</code>
  * Disable CDP
    * <code>sw(config)#no cdp run</code>
  * Enable CDP
    * <code>sw(config)#cdp run</code>
  * Disable CDP per interface
    * <code>sw(config-if)#no cdp enable</code>
  * Enable CDP per interface
    * <code>sw(config-if)#cdp enable</code>

====Verifications====

<code>sw#clear cdp ?    
  counters  Clear CDP counters
  table     Clear cdp table</code>
  
<code>sw#clear cdp counters</code>
<code>sw#clear cdp table</code>

<code>sw#show cdp ?
  entry      Information for specific neighbor entry
  interface  CDP interface status and configuration
  neighbors  CDP neighbor entries
  tlv        CDP optional TLVs
  tlv-list   Information  about specific tlv list
  traffic    CDP statistics
  vlan       Limit CDP info to interfaces on a given vlan
  |          Output modifiers
  <cr>       <cr></code>
  
<code>sw#show cdp entry ?
  *     all CDP neighbor entries
  WORD  Name of CDP neighbor entry</code>
<code>sw#show cdp entry *
-------------------------
Device ID: sw-28.example.com
Entry address(es): 
Platform: cisco C9300-24UX,  Capabilities: Switch IGMP 
Interface: TenGigabitEthernet1/0/18,  Port ID (outgoing port): TenGigabitEthernet1/0/18
Holdtime : 175 sec

Version :
Cisco IOS Software [Fuji], Catalyst L3 Switch Software (CAT9K_IOSXE), Version 16.9.8, RELEASE SOFTWARE (fc4)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2021 by Cisco Systems, Inc.
Compiled Wed 01-Sep-21 01:44 by mcpre

advertisement version: 2
Peer Source MAC: c4b3.6a02.a092
VTP Management Domain: ''
Native VLAN: 5
Duplex: full</code>
<code>sw#show cdp entry sw-28.example.com
-------------------------
Device ID: sw-28.example.com
Entry address(es): 
Platform: cisco C9300-24UX,  Capabilities: Switch IGMP 
Interface: TenGigabitEthernet1/0/18,  Port ID (outgoing port): TenGigabitEthernet1/0/18
Holdtime : 178 sec

Version :
Cisco IOS Software [Fuji], Catalyst L3 Switch Software (CAT9K_IOSXE), Version 16.9.8, RELEASE SOFTWARE (fc4)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2021 by Cisco Systems, Inc.
Compiled Wed 01-Sep-21 01:44 by mcpre

advertisement version: 2
Peer Source MAC: c4b3.6a02.a092
VTP Management Domain: ''
Native VLAN: 5
Duplex: full<code>
sw#show cdp interface 
GigabitEthernet0/0 is administratively down, line protocol is down
  Encapsulation ARPA
  Sending CDP packets every 80 seconds
  Holdtime is 240 seconds</code>
<code>sw#show cdp interface TenGigabitEthernet1/0/1
TenGigabitEthernet1/0/1 is up, line protocol is up
  Encapsulation ARPA
  Sending CDP packets every 80 seconds
  Holdtime is 240 seconds</code>
<code>sw#show cdp neighbors 
Capability Codes: R - Router, T - Trans Bridge, B - Source Route Bridge
                  S - Switch, H - Host, I - IGMP, r - Repeater, P - Phone, 
                  D - Remote, C - CVTA, M - Two-port Mac Relay 

Device ID        Local Intrfce     Holdtme    Capability  Platform  Port ID
sw-28.example.com
                 Ten 1/0/18        140              S I   C9300-24U Ten 1/0/18
sw-28.example.com
                 Ten 1/0/24        142              S I   C9300-24U Ten 1/0/24
sw-28.example.com
                 Ten 1/0/23        140              S I   C9300-24U Ten 1/0/23</code>
<code>sw#show cdp neighbors Ten 1/0/18
Capability Codes: R - Router, T - Trans Bridge, B - Source Route Bridge
                  S - Switch, H - Host, I - IGMP, r - Repeater, P - Phone, 
                  D - Remote, C - CVTA, M - Two-port Mac Relay 

Device ID        Local Intrfce     Holdtme    Capability  Platform  Port ID
sw-28.example.com
                 Ten 1/0/18        149              S I   C9300-24U Ten 1/0/18

Total cdp entries displayed : 1</code>
<code>sw#show cdp neighbors Ten 1/0/18 detail
-------------------------
Device ID: sw-28.example.com
Entry address(es): 
Platform: cisco C9300-24UX,  Capabilities: Switch IGMP 
Interface: TenGigabitEthernet1/0/18,  Port ID (outgoing port): TenGigabitEthernet1/0/18
Holdtime : 166 sec

Version :
Cisco IOS Software [Fuji], Catalyst L3 Switch Software (CAT9K_IOSXE), Version 16.9.8, RELEASE SOFTWARE (fc4)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2021 by Cisco Systems, Inc.
Compiled Wed 01-Sep-21 01:44 by mcpre

advertisement version: 2
Peer Source MAC: c4b3.6a02.a092
VTP Management Domain: ''
Native VLAN: 5
Duplex: full


Total cdp entries displayed : 1</code>

<code>sw#show cdp traffic 
CDP counters :
        Total packets output: 159, Input: 202
        Hdr syntax: 0, Chksum error: 0, Encaps failed: 0
        No memory: 0, Invalid packet: 0, 
        CDP version 1 advertisements output: 0, Input: 0
        CDP version 2 advertisements output: 159, Input: 202</code>
        
        
======Backlinks======
[[cisco:certification_topics:ccie-ei|CCIE-EI v1.1]]\\