Review the following notes before configuring LLDP-MED:
- When 802.1X and LLDP turn on at the same port, switching between LLDP profiles requires a manual reset of all authentication sessions.
- Fortinet recommends LLDP-MED-capable phones.
- The FortiSwitch unit functions as a Network Connectivity device (that is, NIC, switch, router, and gateway), and will only support sending TLVs intended for Network Connectivity devices.
- LLDP supports up to 16 neighbors per physical port.
- The FortiSwitch unit accepts and parses packets using the CDP (Cisco Discovery Protocol) and count CDP neighbors towards the neighbor limit on a physical port. If neighbors exist, the FortiSwitch unit transmits CDP packets in addition to LLDP.
- With release 3.5.1, CDP is independently controllable through the
set cdp-statuscommand on the physical port. The FortiSwitch unit no longer requires a neighbor to trigger it to transmit CDP; it will transmit provided cdp-status is configured as tx-only or tx-rx. The default configuration for CDP-status is disabled. It still uses values pulled from the lldp-profile to configure its contents.
- LLDP must be globally enabled under the
config switch lldp settingscommand for CDP to be transmitted or received:
- If a port is added into a virtual-wire (connects two ends of a controlled system using a radio frequency [RF] medium), the FortiSwitch unit will disable the transmission and receipt of LLDP and CDP packets and remove all neighbors from the port. This virtual-wire state is noted in the
get switch lldp neighbor-summarycommand output.
- If the combination of configured TLVs exceeds the maximum frame size on a port, that frame cannot be sent.
- If a port is configured with an LLDP profile that has
auto-islenabled, the LLDP transmit frequency (normally set under
config switch lldp settingswith the
set tx-intervalcommand) for that port is overridden by the profileʼs
auto-isl-hello-timersetting (the default is 3 seconds).
- When the switch is in FortLink mode, all ports are changed to have profiles with
auto-islenabled by default, and the portsʼ normal transmit interval is overridden by the
auto-isl-hello-timersetting in that profile (the default is 3 seconds).
- The default-auto-isl LLDP profile, which is one of the two default LLDP profiles, has
auto-islenabled. Any port configured with the default-auto-isl profile will transmit LLDP PDUs every 3 seconds when the
auto-isl-hello-timeroption in that profile is set at the default of 3 seconds.
- The Time to Live (TTL) value sent in the LLDP PDUs is still based on the
config switch lldp settings, even if the transmit interval has been overridden by the