--- openflow-2011-09-19-5.h	2015-07-23 09:54:16.692479343 -0700
+++ openflow-2011-09-29-2.h	2015-07-23 09:54:16.696479344 -0700
@@ -733,6 +733,8 @@
 #define OXM_OF_VLAN_PCP   OXM_HEADER  (0x8000, OFPXMT_OFB_VLAN_PCP, 1)
 
 /* The "type of service" byte of the IP header, with the ECN bits forced to 0.
+ * This is actually the DSCP value part of the IPv4 ToS field or the
+ * IPv6 Traffic Class field.
  *
  * Prereqs: OXM_OF_ETH_TYPE must be either 0x0800 or 0x86dd.
  *
@@ -743,6 +745,7 @@
 #define OXM_OF_IP_TOS     OXM_HEADER  (0x8000, OFPXMT_OFB_IP_TOS, 1)
 
 /* The ECN bits of the IP header.
+ * Part of the IPv4 ToS field or the IPv6 Traffic Class field.
  *
  * Prereqs: OXM_OF_ETH_TYPE must be either 0x0800 or 0x86dd.
  *