CDP and LLDP

1. Cisco Discovery Protocol (CDP)

• Cisco proprietary
• CDP messages are sent to mac address 0100.0CCC.CCCC
• Default CDP message timer -> 60 seconds
• Default CDP holdtime -> 180 seconds

1.1 Configuration

R1# show cdp -- Show cpd global details
R1# show cdp interface -- Show the interfaces cdp is enabled on
R1# show cdp neighbors detail -- Show the neighbor table
R1# show cdp traffic -- Show the number of CDP packets sent/received
R1# show cdp entry host-name -- Show detailed information for a specific CDP neighbor
R1(config)# cpd run -- Enable CDP globally
R1(config-if)# cdp enable -- Enable CDP on an interface
R1(config)# cpd timer seconds -- Configure the CDP message timer
R1(config)# cdp holdtime seconds -- Configure the CDP hold time
R1(config)# cdp advertise-v2 -- Enable CDPv2

2. Link Layer Discovery Protocol

• LLDP messages are sent to MAC address 0180.C200.000E
• LLDP message timer -> 30 seconds
• LLDP holdtime -> 120 seconds
• LLDP reinitialization timer -> 2 seconds

2.1 Configuration

R1# show lldp traffic -- show information about LLDP frames sent/received
R1# show lldp -- show global LLDP information
R1# show lldp interface -- show LLDP-enabled interfaces
R1# show lldp neighbors -- show the LLDP neighbor table
R1# show lldp neighbors detail -- show detailed information about all LLDP neighbors
R1# show lldp entry host-name -- show detailed information about a single LLDP neighbor
R1(config)# lldp run -- enable LLDP
R1(config-if)# lldp transmit -- enable LLDP on an interface
R1(config-if)# lldp receive -- enable LLDP on an interface (rx)
R1(config)# lldp timer seconds -- configure the LLDP message timer
R1(config)# lldp reinit seconds

Show cdp neighbors

• The device ID of the neighboring device • The capabilities of the neighboring device • The product number of the neighboring device • The holdtime • The local interface • The remote interface