H3C S6850 Series, Руководство по настройке

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Transmitting and receiving LLDP frames
Transmitting LLDP frames
An LLDP agent operating in TxRx mode or Tx mode sends LLDP frames to its directly connected
devices both periodically and when the local configuration changes. To prevent LLDP frames from
overwhelming the network during times of frequent changes to local device information, LLDP uses
the token bucket mechanism to rate limit LLDP frames. For more information about the token bucket
mechanism, see
ACL and QoS Configuration Guide .
LLDP automatically enables the fast LLDP frame transmission mechanism in either of the following
cases:
•
A new LLDP frame is received and carries device information new to the local device.
•
The LLDP operating mode of the LLDP agent changes from Disable or Rx to TxRx or Tx.
The fast LLDP frame transmission mechanism successively sends the specified number of LLDP
frames at a configurable fast LLDP frame transmission interval. The mechanism helps LLDP
neighbors discover the local device as soon as possible. Then, the normal LLDP frame transmission
interval resumes.
Receiving LLDP frames
An LLDP agent operating in TxRx mode or Rx mode confirms the validity of TLVs carried in every
received LLDP frame. If the TLVs are valid, the LLDP agent saves the information and starts an
aging timer. The initial value of the aging timer is equal to the TTL value in the Time To Live TLV
carried in the LLDP frame. When the LLDP agent receives a new LLDP frame, the aging timer
restarts. When the aging timer decreases to zero, all saved information ages out.
Collaboration with Track
You can configure a track entry and associate it with an LLDP interface. The LLDP module checks
the neighbor availability of the LLDP interface and reports the check result to the Track module. The
Track module changes the track entry status accordingly so the associated application module can
take correct actions.
The Track module changes the track entry status based on the neighbor availability of a monitored
LLDP interface as follows:
•
If the neighbor of the LLDP interface is available, the Track module sets the track entry to
Positive state.
•
If the neighbor of the LLDP interface is unavailable, the Track module sets the track entry to
Negative state.
For more information about collaboration between Track and LLDP, see the track configuration in
High Availability Configuration Guide.
Protocols and standards
•
IEEE 802.1AB-2005, Station and Media Access Control Connectivity Discovery
•
IEEE 802.1AB-2009, Station and Media Access Control Connectivity Discovery
•
ANSI/TIA-1057, Link Layer Discovery Protocol for Media Endpoint Devices
•
IEEE Std 802.1Qaz-2011, Media Access Control (MAC) Bridges and Virtual Bridged Local Area
Networks-Amendment 18: Enhanced Transmission Selection for Bandwidth Sharing Between
Traffic Classes