- Hewlett-Packard Switch User Manual

Configuring for Network Management Applications
LLDP (Link-Layer Discovery Protocol)
LLDP Packet Forwarding: An 802.1D-compliant switch does not forward
LLDP packets, regardless of whether LLDP is globally enabled or disabled on
the switch.
One IP Address Advertisement Per-Port: LLDP advertises only one IP
address per-port, even if multiple IP addresses are configured by lldp config
< port-list > ipAddrEnable on a given port.
802.1Q VLAN Information. LLDP packets do not include 802.1Q header
information, and are always handled as untagged packets.
Effect of 802.1X Operation. If 802.1X port security is enabled on a port
and a connected device is not authorized, LLDP packets are not transmitted
or received on that port. Any neighbor data stored in the neighbor MIB for that
port prior to the unauthorized device connection remains in the MIB until it
ages out. If an unauthorized device later becomes authorized, LLDP transmit
and receive operation resumes.
Neighbor Data Can Remain in the Neighbor Database After the
Neighbor Is Disconnected. After disconnecting a neighbor LLDP device
from the switch, the neighbor can continue to appear in the switch’s neighbor
database for an extended period if the neighbor’s holdtime-multiplier is high;
especially if the refresh-interval is large. Refer to “Changing the Time-to-Live
for Transmitted Advertisements” on page 13-46.
Mandatory TLVs. All mandatory TLVs required for LLDP operation are also
mandatory for LLDP-MED operation.
Determining the Switch Port Number Included in Topology Change
Notification Traps. Enabling topology change notification on a switch port
and then connecting or disconnecting an LLDP-MED endpoint on that port
causes the switch to send an SNMP trap to notify the designated management
station(s). The port number included in the trap corresponds to the internal
number the switch maintains for the designated port, and not the port’s
external (slot/number) identity. To match the port’s external slot/number to
the internal port number appearing in an SNMP trap, use the walkmib ifDescr
command, as shown in the following figure:
13-75