LLDP
The Link Layer Discovery Protocol (LLDP) is a vendor-neutral link layer protocol in the Internet Protocol Suite used by network devices for advertising their identity, capabilities, and neighbors on an IEEE 802 local area network, principally wired Ethernet.[1] The protocol is formally referred to by the IEEE as Station and Media Access Control Connectivity Discovery specified in IEEE 802.1AB and IEEE 802.3-2012 section 6 clause 79.
LLDP performs functions similar to several proprietary protocols, such as Cisco Discovery Protocol, Foundry Discovery Protocol, Nortel Discovery Protocol and Link Layer Topology Discovery.
Information gathered
Information gathered with LLDP is stored in the device as a management information database (MIB) and can be queried with the Simple Network Management Protocol (SNMP) as specified in RFC 2922. The topology of an LLDP-enabled network can be discovered by crawling the hosts and querying this database. Information that may be retrieved include:
System name and description
Port name and description
VLAN name
IP management address
System capabilities (switching, routing, etc.)
MAC/PHY information
MDI power
Link aggregation
Configuration
Enable service with:
set service lldp
Options
Configure a Define management-address:
set service lldp management-address <x.x.x.x>
Define listening interfaces
set service lldp interface <all|interface name>
LLDPd also implements an SNMP subagent. To Enable SNMP queries of the LLDP database:
set service lldp snmp enable
Enable optional/other protocols
set service lldp legacy-protocols cdp
Supported legacy protocols:
cdp
- Listen for CDP for Cisco routers/switches
edp
- Listen for EDP for Extreme routers/switches
fdp
- Listen for FDP for Foundry routers/switches
sonmp
- Listen for SONMP for Nortel routers/switches
Display neighbors
Display with:
show lldp neighbors
Exemple:
vyos@vyos:~# show lldp neighbors
Capability Codes: R - Router, B - Bridge, W - Wlan r - Repeater, S - Station
D - Docsis, T - Telephone, O - Other
Device ID Local Proto Cap Platform Port ID
--------- ----- ----- --- -------- -------
swA309 eth0 LLDP ? Cisco IOS Software, GigE0/33
Options:
detail
- Show lldp neighbors detail
interface
- Show LLDP for specified interface
Troubleshooting
Use operational command show log lldp
to display logs.