Install guide

6 Software Reference
Storing LLDP Information
Whenever an LLDP device receives a valid and current LLDP advertisement
from a neighbouring network device, it stores the information in an IEEE-
defined Simple Network Management Protocol (SNMP) Management
Information Base (MIB). For more information, see Section 12.2 of the IEEE
Standard 802.1AB-2005.
LLDP Local System MIB
Information about your device is called local system information. The LLDP
local system MIB maintains this information, which consists of device details,
as well as any user-configured information that you have set up for your
switch, for example a port description or a management address.
LLDP Remote Systems MIB
Information gained from neighbouring devices is called remote system
information. The LLDP remote systems MIB maintains this information.
The length of time for which neighbour information remains in the LLDP
remote systems MIB is determined by the Time-To-Live (TTL) value of received
LLDPDUs:
■ When an LLDPDU first arrives from a neighbour, the LLDP agent
initializes a timer.
■ As new LLDPDUs arrive from that neighbour, this refreshes the timer.
■ When the timer reaches the TTL value, the LLDP agent deletes the
neighbour’s information from the MIB.
This ensures that only valid LLDP information is stored.
Any remote, organization-specific TLV values are maintained in LLDP's
organizationally-defined remote device LLDP MIB extensions. For more
information, see Section 12 of the IEEE Standard 802.1AB-2005.
Remote tables
change event
Whenever a new neighbour is discovered, or an existing neighbour advertises
a change, for example a new TLV or a change in the TTL, a remote tables
change event is activated. At this time:
■ A trigger and log are activated. For information about LLDP triggers, see
LLDP Triggers on page 10. For information about log messages, see
Appendix A, Messages.
■ If you have notifications enabled, the notification lldpRemTablesChange
is sent. For more information, see “LLDP MIB Notifications” in the IEEE
Standard 802.1AB-2005.
Size limitations To prevent the remote systems MIB from using large amounts of memory and
possibly affecting the operation of your switch, the following limitations are
enforced:
■ The total size of the MIB can be a maximum of 5MB, or 5% of your
available memory - whichever is the lesser amount.
■ There can be a maximum of five neighbours per port.