CDP and LLDP

CDP and LLDP make physical and logical adjacency visible. netverdict models neighbour advertisements, device/interface identity, capabilities, and show output used in labs and diagnostics.

Support level

Area	Level	Notes
CDP	Behaviour model	Cisco-style neighbour discovery and show output.
LLDP	Behaviour model	Standards-style neighbour discovery and show output.
Advertised attributes	Supported	Device ID, port ID, platform/capabilities where available.
Timers	Partial	Deterministic ageing, not full packet interval fidelity.

Standards coverage

Standard	Coverage	Notes
IEEE 802.1AB	Behaviour model	LLDP TLV concepts and neighbour table.
Cisco CDP	Behaviour model	CDP-like neighbour visibility.

Feature matrix

Feature	Status	Notes
Global enable/disable	Supported	CDP/LLDP process state.
Interface enable/disable	Supported	Per-interface participation.
LLDP timers	Supported	Advertisement interval and hold multiplier are stored and used for runtime state.
Neighbour table	Supported	Built from shared-link topology.
Capability display	Supported	Derived from device/interface metadata.
Packet TLV fidelity	Partial	Important fields are represented; not byte-perfect.

Vendor command matrix

Command	IOS-style	Junos-style	VyOS-style	Notes
cdp run	Supported	n/a	n/a	Global CDP.
no cdp enable	Supported	n/a	n/a	Interface disable.
lldp run	Supported	Partial	Partial	Global LLDP.
no lldp run	Supported	n/a	n/a	IOS/IOS-XE command-tree gap closed.
set protocols lldp interface all	n/a	Supported	n/a	Junos commit enables LLDP.
set protocols lldp interface ge-0/0/1 disable	n/a	Supported	n/a	Junos per-interface disable.
set protocols lldp advertisement-interval 20	n/a	Supported	n/a	Junos timer.
set protocols lldp hold-multiplier 4	n/a	Supported	n/a	Junos hold time.
show cdp neighbors	Supported	n/a	n/a	CDP neighbour table.
show lldp neighbors	Supported	Supported	Supported	LLDP neighbour table.
show lldp neighbors detail	Supported	Supported	Partial	Detailed LLDP neighbour table.

Behaviour notes

Discovery tables are derived from the topology and interface state. They are stable and useful for validating cabling assumptions in shared labs.

Examples

Canonical example

configure terminal
cdp run
lldp run
interface GigabitEthernet0/0
 lldp transmit
 lldp receive
end
show cdp neighbors
show lldp neighbors

Vendor styles

IOS-style

cdp run
lldp run
interface GigabitEthernet0/0
 cdp enable
 lldp transmit
 lldp receive

Junos-style

set protocols lldp interface ge-0/0/0
set protocols lldp-med interface ge-0/0/0

VyOS-style

set service lldp interface eth0

Known limits

Full TLV catalogues, power negotiation, LLDP-MED, and exact ageing races are not modelled.