Allied Telesis AT-IFS802SP/POE - Manual (Page 26)

22 AT-IFS802SP/POE(W)-80 User Manual
4.3 Dual Homing Application
Dual Homing function is to prevent the connection lose from between X-Ring group and upper level/
core switch. Assign two ports to be the Dual Homing port that is backup port in the X-Ring group.
The Dual Homing function only works when the X-Ring function is active. Each X-Ring group only has
one Dual Homing port.
[note]
In Dual Homing application architecture, the upper level switches need to enable
the Rapid Spanning Tree protocol.