H3C S5820X SERIES High Availability Configuration Manual

Also see for s5800 series: Installation manual Instruction manual Command reference Quick start Troubleshooting guide

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H3C S5820X SERIES High Availability Configuration Manual Manual pdf 204 page image

192• If the tracked object functions normally, for example, the target interface is up or the target networkis reachable, the state of the track entry is Positive.• If the tracked object functions abnormally, for example, the target interface is down or the targetnetwork is unreachable, the state of the track entry is Negative.• If the detection result is not valid, for example, the NQA test group that is associated with the trackentry does not exist, the state of the track entry is Invalid.The following detection modules can be associated with the track module:• NQA• BFD• Interface management moduleCollaboration between the track module and an application moduleWhen the status of the track entry changes, the track module notifies the associated application module,which then takes proper actions.The following application modules can be associated with the track module:• Virtual Router Redundancy Protocol (VRRP)• Static routing• Policy-based routingIn some cases, when the status of a track entry changes, if the track module immediately notifies theapplication modules, 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. Whenthe uplink interface fails, the track module notifies the master to reduce its priority so that a backup witha higher priority can preempt as the master to forward packets. When the uplink interface recovers, if thetrack module immediately notifies the original master to restore its priority, the master will immediatelyforward packets; however, the uplink route has not been recovered yet, which may result in packetforwarding failure. Then configure the track module to notify the application modules of the track entrystatus change after a specified delay time.Collaboration application exampleThe 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 staticroute is valid. If the next hop becomes unreachable, the static route should become invalid. For thispurpose, 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 192.168.0.88is reachable, the track entry is in the Positive state. When the next hop becomes unreachable, thetrack entry is in the Negative state.3. Associate the track entry with the static route. When the track entry turns to the Positive state, thestatic route is valid. When the associated track entry turns to the Negative state, the static route isinvalid.Track configuration task listTo implement the collaboration function, establish associations between the track module and thedetection modules, and between the track module and the application modules.