quoting to prevent the shell from breaking the description into
multiple arguments.)
.PP
+Flow descriptions should be in \fBnormal form\fR. This means that a
+flow may only specify a value for an L3 field if it also specifies a
+particular L2 protocol, and that a flow may only specify an L4 field
+if it also specifies particular L2 and L3 protocol types. For
+example, if the L2 protocol type \fBdl_type\fR is wildcarded, then L3
+fields \fBnw_src\fR, \fBnw_dst\fR, and \fBnw_proto\fR must also be
+wildcarded. Similarly, if \fBdl_type\fR or \fBnw_proto\fR (the L3
+protocol type) is wildcarded, so must be \fBtp_dst\fR and
+\fBtp_src\fR, which are L4 fields. \fBovs\-ofctl\fR will warn about
+flows not in normal form.
+.PP
The following field assignments describe how a flow matches a packet.
If any of these assignments is omitted from the flow syntax, the field
is treated as a wildcard; thus, if all of them are omitted, the
IPv4 and Ethernet.
.IP
When \fBdl_type\fR is wildcarded or set to a value other than 0x0800
-or 0x0806, the values of \fBnw_src\fR and \fBnw_dst\fR are silently
-ignored.
+or 0x0806, the values of \fBnw_src\fR and \fBnw_dst\fR are ignored
+(see \fBFlow Syntax\fR above).
.
.IP \fBnw_proto=\fIproto\fR
When \fBip\fR or \fBdl_type=0x0800\fR is specified, matches IP
0.
.IP
When \fBdl_type\fR is wildcarded or set to a value other than 0x0800
-or 0x0806, the value of \fBnw_proto\fR is silently ignored.
+or 0x0806, the value of \fBnw_proto\fR is ignored (see \fBFlow
+Syntax\fR above).
.
.IP \fBnw_tos=\fItos\fR
Matches IP ToS/DSCP field \fItos\fR, which is specified as a decimal
number between 0 and 255, inclusive. Note that the two lower reserved
bits are ignored for matching purposes.
.IP
-The value of \fBnw_proto\fR is silently ignored unless
-\fBdl_type=0x0800\fR, \fBip\fR, \fBicmp\fR, \fBtcp\fR, or \fBudp\fR is
-also specified.
+The value of \fBnw_proto\fR is ignored unless \fBdl_type=0x0800\fR,
+\fBip\fR, \fBicmp\fR, \fBtcp\fR, or \fBudp\fR is also specified (see
+\fBFlow Syntax\fR above).
.
.IP \fBtp_src=\fIport\fR
.IQ \fBtp_dst=\fIport\fR
from a HTTP server).
.IP
When \fBdl_type\fR and \fBnw_proto\fR take other values, the values of
-these settings are silently ignored.
+these settings are ignored (see \fBFlow Syntax\fR above).
.
.IP \fBicmp_type=\fItype\fR
.IQ \fBicmp_code=\fIcode\fR
as a decimal number between 0 and 255, inclusive.
.IP
When \fBdl_type\fR and \fBnw_proto\fR take other values, the values of
-these settings are silently ignored.
+these settings are ignored (see \fBFlow Syntax\fR above).
.
.PP
The following shorthand notations are also available: