This counts Force Switch (FS) RAPS PDUs received on the west link, meaning a manual force-switch command issued at another node has propagated to and been received by this node. This tells an admin that a force-switch active somewhere on the ring is affecting this virtual ring's west side even though the command wasn't issued locally, which matters when trying to figure out which physical device in the ring actually holds the active force-switch command that needs to be cleared. For example, if this counter is nonzero while this node's own west-link force object shows off, the force-switch causing the ring's current behavior was issued on a different node and needs to be cleared there, not here.