H3C Technologies H3C S7500E Series Switches - Manual (Page 183)

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z If the probe fails, the status of the corresponding track entry is Negative.
If the probe result is invalid (for example, the NQA test group collaborating with the track entry does
not exist.), the status of the track entry is Invalid.
At present, the detection modules that can collaborate with the track module include the Network
Quality Analyzer (NQA) module, the Bidirectional Forwarding Detection (BFD) module and the
interface management module.
z Refer to NQA Configuration in the Network Management and Monitoring Command Reference for
details of NQA.
z Refer to BFD Configuration in the High Availability Configuration Guide for details of BFD.
z The interface management module is used to monitor the physical status or Layer 3 protocol
status of an interface. When the physical status or Layer 3 protocol status of an interface is up,
the status of a track entry is Positive; when the physical status or Layer 3 protocol status of an
interface is down, the status of a track entry is Negative.
Collaboration Between the Track Module and the Application Modules
You can establish the collaboration between the track module and the application modules through
configuration. If the status of the track entry changes, the track module notifies the application
modules to deal with the change accordingly.
At present, the application modules that can collaborate with the track module include:
z VRRP( Virtual Router Redundancy Protocol )
z Static routing
In some cases, when the status of the track entry changes, if the track module notifies the application
modules immediately, communication may be interrupted because routes cannot be recovered in time.
For example, the master in a VRRP group monitors the uplink interface through the track module.
When the uplink interface fails, the track module notifies the master to reduce its priority so that a
backup with a higher priority can preempt as the master to forward packets. When the uplink interface
recovers, if the track module notifies the original master to restore its priority immediately, the master
will forward packets immediately; however, the uplink route has not been recovered yet, which may
result in packet forwarding failure. In this case, you can configure that the track module notifies the
application modules of the track entry status change after a specified delay time.
Track Configuration Task List
To implement the collaboration function, you need to establish collaboration between the track module
and the detection modules, and between the track module and the application modules.
Complete these tasks to configure track module: