Luxul XMS-1024P - Manual (Page 239)

239
User Guide
© 2014 Luxul. All Rights Reserved.
Other trademarks and registered trademarks are the property of their respective owners
Note: When an Alarm Variable exceeds the Threshold on the same Entry
continuously, an Alarm Event will only be generated the first time
the Threshold is exceeded. The Rising Alarm and Falling Alarm are
triggered independently, so a Rising Alarm would not be considered
a reason to block a Falling Alarm.
14 LLDP
LLDP (Link Layer Discovery Protocol) is a Layer 2 protocol that is used to allow Network
devices to advertise their Device Information to neighbors in the same Local Area
Network. The advertised Information, including details such as Device Identification,
Capabilities and Configuration Settings is forwarded in TLV (Type/Length/Value)
format according to the IEEE 802.1ab standard. The TLVs are encapsulated in LLDPDU
(Link Layer Discovery Protocol Data Unit) packets. The LLDPDU packets are distributed
via LLDP and is stored by its recipients in the MIB (Management Information Base).
This makes it possible for the information to be accessed by a Network Management
System (NMS) using a Management protocol such as SNMP (Simple Network
Management Protocol).
An IETF Standard MIB, as well as a number of vendor specific MIBs, have been created
to describe a Network’s physical topology and associated systems within that topol-
ogy. There is no standard protocol for populating these MIBs or communicating this
information among stations on the LAN. The LLDP protocol is a stop gap protocol that
accomplishes this task. A Device running LLDP can Automatically Discover and Learn
about neighbors allowing for interoperability between Network devices from different
vendors. For instance, this protocol allows two systems running different Network Layer
protocols to learn about each other.
LLDP-MED (Link Layer Discovery Protocol for Media Endpoint Devices) is an extension
of LLDP intended for managing endpoint devices such as Voice over IP Phones and
Network Switches. The LLDP-MED TLVs advertise information such as Network Policy,
Power via MDI, Inventory Management information and Device Location details.
LLDP and LLDP-MED information can be used by SNMP applications to simplify trouble-
shooting, enhance Network Management, and maintain an accurate Network topology.
LLDPDU Format
Each LLDPDU includes an ordered sequence of three required TLVs followed by one or
more optional TLVs and an End of LLDPDU TLV as shown in the figure below. Chassis ID
TLV, Port ID TLV, TTL TLV and End TLV are the four required TLVs in an LLDPDU. Optional
TLVs provide various details about the LLDP Agent advertising them and are selected by
Network Management.