H3C Technologies H3C WX3000E Series Wireless Switches - Manual (Page 625)

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Configuring stateful failover
NOTE:
Support for the stateful failover feature may vary depending on your device model. For more information,
see "Feature matrixes."
Overview
Introduction to stateful failover
Some customers require their wireless networks to be highly reliable to ensure continuous data
transmission. In Figure 652 , deploying only one AC (even with high reliability) risks a single point of
failure and therefore cannot meet the requirement.
Figure 652 Network with one AC deployed
The stateful failover feature (supporting portal service) was introduced to meet the requirement. In Figure
653 , two ACs that are enabled with stateful failover are deployed in the network. You need to specify a
VLAN on the two ACs as the backup VLAN, and add the interfaces between the ACs to the backup
VLAN. The backup VLAN is like a failover link, through which the two ACs exchange state negotiation
messages periodically. After the two ACs enter the synchronization state, they back up the service entries
of each other to make sure that the service entries on them are consistent. If one AC fails, the other AC,
which has already backed up the service information, can take over the services, thus avoiding service
interruption.