802.1AB Overview Configuring 802.1AB
page 19-6 OmniSwitch AOS Release 6 Network Configuration Guide September 2009
• Device location discovery to allow creation of location databases and, in the case of VoIP, E911
services.
• Extended and automated power management of Power over Ethernet endpoints.
• Inventory management, allowing network administrators to track their network devices, and determine
their characteristics (manufacturer, software and hardware versions, and serial / asset number).
• Support for receiving and storing of Network Policy TLV from remote Network Connectivity Devices
and Endpoint Devices.
• Support for receiving and storing of Inventory Management TLVs from remote Endpoint Devices.
Note. The OmniSwitch only supports receiving and storing of the Network Policy and Inventory Manage-
ment TLVs.
LLDP Agent Operation
A network device that implements LLDP, supports an LLDP agent. An LLDP agent operates in any one of
the following three modes:
Transmit-only mode: The agent can only transmit the information about the capabilities and the current
status of the local system at regular intervals.
Receive-only mode: The agent can only receive information about the capabilities and the current status
of the remote systems.
Transmit and receive mode: The agent can transmit the capabilities and status information of the local
system and receive the capabilities and the status information of the remote system.
LLDPDU Transmission and Reception
LLDP operates in a one-way direction, so that the information in the LLDPDUs flows from one device to
another. LLDPDUs are not exchanged as an information request by one device and a response sent by
another device. The other devices do not acknowledge LLDP information received from a device.
The transmission of LLDPDU is based on two factors:
• Transmit countdown timing counter. For example, whenever the counter expires, it will go through the
entire database of ports that have links and send the LLDPDU if the current time has surpassed the re-
transmission time interval.
• If there is change in status of any of the ports. For example, a new port is attached or a new link has
come up.
Reception of LLDPDU is a two phase process:
• LLDPDU and TLV error handling as per the 802.1AB standard.
• LLDP remote system MIB update.
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