How Lldp Works - HP A6600 Configuration Manual

Type
Location Identification
Management address
The management address of a router is used by the network management system to identify and manage
the router for topology maintenance and network management. The management address is
encapsulated in the management address TLV.

How LLDP works

Operating Modes of LLDP
LLDP can operate in one of the following modes:
TxRx mode. A port in this mode sends and receives LLDPDUs.
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Tx mode. A port in this mode only sends LLDPDUs.
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Rx mode. A port in this mode only receives LLDPDUs.
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Disable mode. A port in this mode does not send or receive LLDPDUs.
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When the LLDP operating mode of a port changes, its LLDP protocol state machine re-initializes. To
prevent LLDP from being initialized too frequently during times of frequent operating mode change, can
configure a re-initialization delay. With this delay configured, a port must wait for the specified interval
before it can initialize LLDP after the LLDP operating mode changes.
Transmitting LLDPDUs
An LLDP-enabled port operating in TxRx mode or Tx mode sends LLDPDUs to its directly connected devices
both periodically and when the local configuration changes. To prevent the network from being
overwhelmed by LLDPDUs during times of frequent local device information change, an interval is
introduced between two successive LLDPDUs.
This interval is shortened to 1 second in either of the following cases:
A new neighbor is discovered. A new LLDPDU is received carrying device information new to the
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local device.
The LLDP operating mode of the port changes from Disable/Rx to TxRx or Tx.
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This is the fast sending mechanism of LLDP. This feature sends a specific number of LLDPDUs at the
1-second interval to help LLDP neighbors discover the local device as soon as possible. Then, the normal
LLDPDU transmit interval resumes.
Receiving LLDPDUs
An LLDP-enabled port operating in TxRx mode or Rx mode checks the validity of TLVs carried in every
received LLDPDU. If valid, the information is saved and an aging timer is set for it based on the TTL value
in the Time To Live TLV carried in the LLDPDU. If the TTL value is zero, the information is aged out
immediately.
Description
Allows a network device to advertise the appropriate location
identifier information for a terminal device to use in the context of
location-based applications.
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