H3C Technologies H3C S12500 Series Switches - Manual (Page 211)

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Detection modules that can be associated with the Track module include:
• NQA
• BFD
• Interface management module
Collaboration between the Track module and an application module
After being associated with an application module, when the status of the track entry changes, the Track
module notifies the application module, which then takes proper actions.
Application modules that can be associated with the Track module include:
• Virtual Router Redundancy Protocol (VRRP)
• Static routing
• Policy-based routing
In some cases, when the status of the track entry changes, if the Track module notifies the application
modules immediately, communication might 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 might result in packet
forwarding failure. Then configure the Track module to wait a specified delay time before notifying the
application modules of the track entry status change.
Collaboration application example
The following describes how NQA, Track, and static routing collaborate.
Configure a static route with next hop 192.168.0.88 on the device. If the next hop is reachable, the static
route is valid. If the next hop becomes unreachable, the static route should become invalid. For this
purpose, configure collaboration between the NQA, Track, and static routing modules:
1. Create an NQA test group to monitor the reachability of IP address 192.168.0.88.
2. Create a track entry and associate it with the NQA test group. When the next hop 192.168.0.88
is reachable, the track entry is in Positive state. When the next hop becomes unreachable, the track
entry is in Negative state.
3. Associate the track entry with the static route. When the track entry turns to the Positive state, the
static route is valid. When the associated track entry turns to the Negative state, the static route is
invalid.
Track configuration task list
To implement the collaboration function, establish associations between the Track module and the
detection modules, and between the Track module and the application modules.
Complete these tasks to configure the Track module: