-/* Expires all MAC learning entries associated with 'port' and forces ofproto
- * to revalidate every flow. */
+/* Expires all MAC learning entries associated with 'bundle' and forces its
+ * ofproto to revalidate every flow.
+ *
+ * Normally MAC learning entries are removed only from the ofproto associated
+ * with 'bundle', but if 'all_ofprotos' is true, then the MAC learning entries
+ * are removed from every ofproto. When patch ports and SLB bonds are in use
+ * and a VM migration happens and the gratuitous ARPs are somehow lost, this
+ * avoids a MAC_ENTRY_IDLE_TIME delay before the migrated VM can communicate
+ * with the host from which it migrated. */