diff --git a/include/proto/dumpstats.h b/include/proto/dumpstats.h
index 2bdc3b1..0fb3477 100644
--- a/include/proto/dumpstats.h
+++ b/include/proto/dumpstats.h
@@ -54,6 +54,181 @@
 #define STAT_SCOPE_INPUT_NAME "scope" /* pattern form scope name <input> in html form */
 #define STAT_SCOPE_PATTERN    "?" STAT_SCOPE_INPUT_NAME "="
 
+/* This level of detail is needed to let the stats consumer know how to
+ * aggregate them (eg: between processes or cluster nodes). Only a few
+ * combinations are actually in use, though the mechanism tends to make
+ * this easy to extend to future uses.
+ *
+ * Each reported stats element is typed based on 4 dimensions :
+ *  - the field format : it indicates the validity range of the reported value,
+ *    its limits and how to parse it. 6 types are currently supported :
+ *    empty, signed 32-bit integer, unsigned 32-bit integer, signed 64-bit
+ *    integer, unsigned 64-bit integer, string
+ *
+ *  - the field origin : how was the value retrieved and what it depends on.
+ *    5 origins are currently defined : product (eg: haproxy version or
+ *    release date), configuration (eg: a configured limit), key (identifier
+ *    used to group values at a certain level), metric (a measure of something),
+ *    status (something discrete which by definition cannot be averaged nor
+ *    aggregated, such as "listening" versus "full").
+ *
+ *  - the field nature : what does the data represent, implying how to aggregate
+ *    it. At least 9 different natures are expected : counter (an increasing
+ *    positive counter that may wrap when its type is overflown such as a byte
+ *    counter), gauge (a measure at any instant that may vary, such as a
+ *    concurrent connection count), a limit (eg: maximum acceptable concurrent
+ *    connections), a minimum (eg: minimum free memory over a period), a
+ *    maximum (eg: highest queue length over a period), an event rate (eg:
+ *    incoming connections per second), a duration that is often aggregated by
+ *    taking the max (eg: service uptime), an age that generally reports the
+ *    last time an event appeared and which generally is aggregated by taking
+ *    the most recent event hence the smallest one, the time which reports a
+ *    discrete instant and cannot obviously be averaged either, a name which
+ *    will generally be the name of an entity (such as a server name or cookie
+ *    name), an output which is mostly used for various unsafe strings that are
+ *    retrieved (eg: last check output, product name, description, etc), and an
+ *    average which indicates that the value is relative and meant to be averaged
+ *    between all nodes (eg: response time, throttling, etc).
+ *
+ *  - the field scope : if the value is shared with other elements, which ones
+ *    are expected to report the same value. The first scope with the least
+ *    share is the process (most common one) where all data are only relevant
+ *    to the process being consulted. The next one is the service, which is
+ *    valid for all processes launched together (eg: shared SSL cache usage
+ *    among processes). The next one is the system (such as the OS version)
+ *    and which will report the same information for all instances running on
+ *    the same node. The next one is the cluster, which indicates that the
+ *    information are shared with other nodes being part of a same cluster.
+ *    Stick-tables may carry such cluster-wide information. Larger scopes may
+ *    be added in the future such as datacenter, country, continent, planet,
+ *    galaxy, universe, etc.
+ *
+ * All these information will be encoded in the field as a bit field so that
+ * it is easy to pass composite values by simply ORing elements above, and
+ * to ease the definition of a few field types for the most common field
+ * combinations.
+ *
+ * The enums try to be arranged so that most likely characteristics are
+ * assigned the value zero, making it easier to add new fields.
+ *
+ * Field format has precedence over the other parts of the type. Please avoid
+ * declaring extra formats unless absolutely needed. The first one, FF_EMPTY,
+ * must absolutely have value zero so that it is what is returned after a
+ * memset(0). Furthermore, the producer is responsible for ensuring that when
+ * this format is set, all other bits of the type as well as the values in the
+ * union only contain zeroes. This makes it easier for the consumer to use the
+ * values as the expected type.
+ */
+
+enum field_format {
+	FF_EMPTY    = 0x00000000,
+	FF_S32      = 0x00000001,
+	FF_U32      = 0x00000002,
+	FF_S64      = 0x00000003,
+	FF_U64      = 0x00000004,
+	FF_STR      = 0x00000005,
+	FF_MASK     = 0x000000FF,
+};
+
+enum field_origin {
+	FO_METRIC   = 0x00000000,
+	FO_STATUS   = 0x00000100,
+	FO_KEY      = 0x00000200,
+	FO_CONFIG   = 0x00000300,
+	FO_PRODUCT  = 0x00000400,
+	FO_MASK     = 0x0000FF00,
+};
+
+enum field_nature {
+	FN_GAUGE    = 0x00000000,
+	FN_LIMIT    = 0x00010000,
+	FN_MIN      = 0x00020000,
+	FN_MAX      = 0x00030000,
+	FN_RATE     = 0x00040000,
+	FN_COUNTER  = 0x00050000,
+	FN_DURATION = 0x00060000,
+	FN_AGE      = 0x00070000,
+	FN_TIME     = 0x00080000,
+	FN_NAME     = 0x00090000,
+	FN_OUTPUT   = 0x000A0000,
+	FN_AVG      = 0x000B0000,
+	FN_MASK     = 0x00FF0000,
+};
+
+enum field_scope {
+	FS_PROCESS  = 0x00000000,
+	FS_SERVICE  = 0x01000000,
+	FS_SYSTEM   = 0x02000000,
+	FS_CLUSTER  = 0x03000000,
+	FS_MASK     = 0xFF000000,
+};
+
+struct field {
+	uint32_t type;
+	union {
+		int32_t     s32; /* FF_S32 */
+		uint32_t    u32; /* FF_U32 */
+		int64_t     s64; /* FF_S64 */
+		uint64_t    u64; /* FF_U64 */
+		const char *str; /* FF_STR */
+	} u;
+};
+
+static inline enum field_format field_format(const struct field *f, int e)
+{
+	return f[e].type & FF_MASK;
+}
+
+static inline enum field_origin field_origin(const struct field *f, int e)
+{
+	return f[e].type & FO_MASK;
+}
+
+static inline enum field_scope field_scope(const struct field *f, int e)
+{
+	return f[e].type & FS_MASK;
+}
+
+static inline enum field_nature field_nature(const struct field *f, int e)
+{
+	return f[e].type & FN_MASK;
+}
+
+static inline const char *field_str(const struct field *f, int e)
+{
+	return (field_format(f, e) == FF_STR) ? f[e].u.str : "";
+}
+
+static inline struct field mkf_s32(uint32_t type, int32_t value)
+{
+	struct field f = { .type = FF_S32 | type, .u.s32 = value };
+	return f;
+}
+
+static inline struct field mkf_u32(uint32_t type, uint32_t value)
+{
+	struct field f = { .type = FF_U32 | type, .u.u32 = value };
+	return f;
+}
+
+static inline struct field mkf_s64(uint32_t type, int64_t value)
+{
+	struct field f = { .type = FF_S64 | type, .u.s64 = value };
+	return f;
+}
+
+static inline struct field mkf_u64(uint32_t type, uint64_t value)
+{
+	struct field f = { .type = FF_U64 | type, .u.u64 = value };
+	return f;
+}
+
+static inline struct field mkf_str(uint32_t type, const char *value)
+{
+	struct field f = { .type = FF_STR | type, .u.str = value };
+	return f;
+}
+
 extern struct applet http_stats_applet;
 
 void stats_io_handler(struct stream_interface *si);