-is initially zero, no decrement occurs. Instead, a ``packet-in'' message
-with reason code \fBOFPR_INVALID_TTL\fR is sent to each connected
-controller with controller id zer that has enabled receiving them.
+is initially zero or decrementing would make it so, no decrement occurs.
+Instead, a ``packet-in'' message with reason code \fBOFPR_INVALID_TTL\fR
+is sent to the main controller (id zero), if it has enabled receiving them.