The Link Layer Discovery Protocol 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.
Ideally, this is great to use to make sure that switches are talking to each other prior to creating trunk ports.
The default setting for LLDP on the Cisco (and Juniper) devices are all we need to ensure that devices are talking to each other.
ON CISCO DEVICE:
To verifiy the LLDP connection…
ON JUNIPER DEVICE:
To verifiy the LLDP connection… (NOTE: you must be in CLI mode and not CONFIGURATION mode)