- /* Throughout this file, "probe" is shorthand for "inactivity probe".
- * When nothing has been received from the peer for a while, we send out
- * an echo request as an inactivity probe packet. We should receive back
- * a response. */
+ /* Throughout this file, "probe" is shorthand for "inactivity probe". When
+ * no activity has been observed from the peer for a while, we send out an
+ * echo request as an inactivity probe packet. We should receive back a
+ * response.
+ *
+ * "Activity" is defined as either receiving an OpenFlow message from the
+ * peer or successfully sending a message that had been in 'txq'. */