H3C Technologies H3C MSR 50 - Manual (Page 31)

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• 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.
The following application modules can be associated with the Track module:
• VRRP.
• Static routing.
• Policy-based routing.
• Interface backup.
In some cases, the status of a track entry changes while a route is still recovering. This leads to problems
if the Track module immediately notifies the application modules of the status change and the application
modules begin using the route before it is ready.
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 failed uplink interface recovers,
if the Track module immediately notifies the original master to restore its priority, the master immediately
will forward packets to that interface. However, this result in packet forwarding failure because the uplink
route has not yet been recovered.
To solve this problem, configure a delay before the Track module notifies the application modules of the
track entry status changes.
Collaboration application example
The following is an example of collaboration between NQA, Track, and static routing.
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 accessibility 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 Positive state, the static
route is valid. When the associated track entry turns to Negative state, the static route is invalid.
Collaboration application example on an AC
This example shows how to implement collaboration between NQA, Track and uplink detection.