Brocade Communications Systems FCX Series Hardware Installation Manual page 47

In ring stack topology, there is an extra connection between the logical first and last devices forming
a"ring" or "closed-loop." The closed-loop connection provides a redundant path for the stack link, so if
one link fails, stack communications can be maintained.
Brocade FCX Series Hardware Installation Guide
53-1002977-01
Installing the FCX Switch
45