. ns
. IP "\\$1"
..
-.TH ovs\-ofctl 8 "January 2010" "Open vSwitch" "Open vSwitch Manual"
+.TH ovs\-ofctl 8 "January 2011" "Open vSwitch" "Open vSwitch Manual"
.ds PN ovs\-ofctl
.
.SH NAME
.IP
When \fBdl_type\fR and \fBnw_proto\fR take other values, the values of
these settings are ignored (see \fBFlow Syntax\fR above).
+.
+.PP
+The following field assignments require support for the NXM (Nicira
+Extended Match) extension to OpenFlow. When one of these is specified,
+\fBovs\-ofctl\fR will automatically attempt to negotiate use of this
+extension. If the switch does not support NXM, then \fBovs\-ofctl\fR
+will report a fatal error.
+.
.IP \fBtun_id=\fItunnel-id\fR[\fB/\fImask\fR]
Matches tunnel identifier \fItunnel-id\fR. Only packets that arrive
over a tunnel that carries a key (e.g. GRE with the RFC 2890 key
extension) will have a nonzero tunnel ID. If \fImask\fR is omitted,
-\fItunnel-id\fR is the exact tunnel ID to match; \fImask\fR is
+\fItunnel-id\fR is the exact tunnel ID to match; if \fImask\fR is
specified, then a 1-bit in \fImask\fR indicates that the corresponding
bit in \fItunnel-id\fR must match exactly, and a 0-bit wildcards that
bit.
.IP
-\fBtun_id\fR requires use of one of two Nicira extensions to OpenFlow:
-.RS
-.IP "NXM (Nicira Extended Match)"
-This extension fully supports \fBtun_id\fR.
-.IP "Tunnel ID from Cookie"
-This extension supports \fBtun_id\fR with three caveats: the top 32 bits
-of the \fBcookie\fR (see below) are used for \fItunnel-id\fR and thus
-unavailable for other use, specifying \fBtun_id\fR on
-\fBdump\-flows\fR or \fBdump\-aggregate\fR has no effect, and
-\fImask\fR is not supported.
-.RE
-.IP
-When \fBtun_id\fR is specified, \fBovs\-ofctl\fR will automatically
-attempt to negotiate use of one of these extensions. It will use the
-``tunnel ID from cookie'' extension if neither caveat applies and NXM
-otherwise. If the switch does not support the needed extension, then
-\fBovs\-ofctl\fR will report a fatal error.
+In an attempt to be compatible with more switches, \fBovs\-ofctl\fR will
+prefer to use the ``tunnel ID from cookie'' Nicira extension to NXM.
+The use of this extension comes with three caveats: the top 32 bits of
+the \fBcookie\fR (see below) are used for \fItunnel-id\fR and thus
+unavailable for other use, specifying \fBtun_id\fR on \fBdump\-flows\fR
+or \fBdump\-aggregate\fR has no effect, and \fImask\fR is not supported.
+If any of these caveats apply, \fBovs-ofctl\fR will use NXM.
+.
.IP "\fBreg\fIidx\fB=\fIvalue\fR[\fB/\fImask\fR]"
Matches \fIvalue\fR either exactly or with optional \fImask\fR in
register number \fIidx\fR. The valid range of \fIidx\fR depends on
.IP
When a packet enters an OpenFlow switch, all of the registers are set
to 0. Only explicit Nicira extension actions change register values.
-.IP
-Register matches require support for the NXM (Nicira Extended Match)
-extension to OpenFlow. When a register match is specified,
-\fBovs\-ofctl\fR will automatically attempt to negotiate use of this
-extension. If the switch does not support NXM, then \fBovs\-ofctl\fR
-will report a fatal error.
.
.PP
The following shorthand notations are also available: