Owner's Manual

Chapter 6. LLDP | 151
NETGEAR 8800 User Manual
The information distributed using LLDP is stored by its recipients in a standard Management
Information Base (MIB), making it possible for the information to be accessed by a Network
Management System (NMS) using a management protocol such as the Simple Network
Management Protocol (SNMP).
LLDP transmits periodic advertisements containing device information and media-specific
configuration information to neighbors attached to the same network. LLDP agents cannot
solicit information from other agents by way of this protocol. The switch can transmit and
receive LLDP media endpoint discovery (MED) TLVs. Once enabled, the LLDP MED TLVs
messages are sent only after a neighbor is detected sending out LLDP MED TLVs; the LLDP
MED TLVs are transmitted only after the switch receives an LLDP MED TLV from a neighbor.
For this reason, two connected switches will never exchange LLDP MED TLVs.
Note: Network connectivity devices wait to detect LLDP MED TLVs from
endpoints before they send out LLDP MED TLVs; so 2 network
connectivity devices will not exchange LLDP MED messages.
The TLV format with link layer control frames is used to communicate with other LLDP
agents. LLDP agents also receive link layer control frames, extract the information from
TLVs, and store them in LLDP MIB objects.
If the information values from the device change at any time, the LLDP agent is notified. The
agent then sends an update with the new values, which is referred to as a triggered update. If
the information for multiple elements changes in a short period, the changes are bundled
together and sent as a single update to reduce network load.
You configure LLDP per port, and each port can store received information for a maximum of
four neighbors.
Note: LLDP runs with link aggregation.
The device can also support the following types of LLDP TLVs:
• Avaya-NETGEAR Networks proprietary TLVs
• LLDP media endpoint discovery (MED) TLVs
The software supports several TLVs that are proprietary to Avaya and NETGEAR
(avaya-NETGEAR TLVs). These TLVs primarily advertise and receive information for Avaya
voice over IP (VoIP) telephones. Some of these TLVs primarily concern the PD; the PD
receives these TLVs, but does not transmit them. (See
Table 19 for a listing of the proprietary
TLVs that are only received by the switch.) These proprietary LLDPs are transmitted and
received as soon as you enable LLDP and configure the specified TLVs.
LLDP MED TLVs are sent only after the device detects a neighbor transmitting LLDP MED
TLVs; and the LLDP MED TLVs must be configured and enabled prior to the detection. You
must enable the LLDP-MED capabilities TLV before configuring and enabling any other LLDP