+/* lengths (fixed or minimal) of particular protocol structures */
+#define OF_SWITCH_CONFIG_LEN 12
+#define OF_PHY_PORT_LEN 48
+#define OF_SWITCH_FEATURES_LEN 32
+#define OF_PORT_STATUS_LEN 64
+#define OF_PORT_MOD_LEN 32
+#define OF_PACKET_IN_LEN 20
+#define OF_ACTION_OUTPUT_LEN 8
+#define OF_ACTION_VLAN_VID_LEN 8
+#define OF_ACTION_VLAN_PCP_LEN 8
+#define OF_ACTION_DL_ADDR_LEN 16
+#define OF_ACTION_NW_ADDR_LEN 8
+#define OF_ACTION_TP_PORT_LEN 8
+#define OF_ACTION_NW_TOS_LEN 8
+#define OF_ACTION_VENDOR_HEADER_LEN 8
+#define OF_ACTION_HEADER_LEN 8
+#define OF_PACKET_OUT_LEN 16
+#define OF_MATCH_LEN 40
+#define OF_FLOW_MOD_LEN 72
+#define OF_FLOW_REMOVED_LEN 88
+#define OF_ERROR_MSG_LEN 12
+#define OF_STATS_REQUEST_LEN 12
+#define OF_STATS_REPLY_LEN 12
+#define OF_DESC_STATS_LEN 1056
+#define OF_FLOW_STATS_REQUEST_LEN 44
+#define OF_FLOW_STATS_LEN 88
+#define OF_AGGREGATE_STATS_REQUEST_LEN 44
+#define OF_AGGREGATE_STATS_REPLY_LEN 24
+#define OF_TABLE_STATS_LEN 64
+#define OF_PORT_STATS_REQUEST_LEN 8
+#define OF_PORT_STATS_LEN 104
+#define OF_VENDOR_HEADER_LEN 12
+#define OF_QUEUE_PROP_HEADER_LEN 8
+#define OF_QUEUE_PROP_MIN_RATE_LEN 16
+#define OF_PACKET_QUEUE_LEN 8
+#define OF_QUEUE_GET_CONFIG_REQUEST_LEN 12
+#define OF_QUEUE_GET_CONFIG_REPLY_LEN 16
+#define OF_ACTION_ENQUEUE_LEN 16
+#define OF_QUEUE_STATS_REQUEST_LEN 8
+#define OF_QUEUE_STATS_LEN 32
+
+/* miscellaneous constants from [OF10] */
+#define OFP_MAX_TABLE_NAME_LEN 32
+#define OFP_MAX_PORT_NAME_LEN 16
+#define DESC_STR_LEN 256
+#define SERIAL_NUM_LEN 32
+#define OFP_VLAN_NONE 0xffff