.TH ovs\-openflowd 8 "March 2009" "Open vSwitch" "Open vSwitch Manual"
+.\" This program's name:
.ds PN ovs\-openflowd
+.\" SSL peer program's name:
+.ds SN ovs\-controller
.
.SH NAME
ovs\-openflowd \- OpenFlow switch implementation
.so lib/dpif.man
.
.PP
-The optional \fIcontroller\fR arguments specify how to connect to
-the OpenFlow controller. It takes one of the following forms:
+The optional \fIcontroller\fR arguments specify how to connect to the
+OpenFlow controller or controllers. Each takes one of the following
+forms:
.
.so lib/vconn-active.man
.
.PP
+When multiple controllers are configured, \fBovs\-openflowd\fR
+connects to all of them simultaneously. OpenFlow 1.0 does not specify
+how multiple controllers coordinate in interacting with a single
+switch, so more than one controller should be specified only if the
+controllers are themselves designed to coordinate with each other.
+(The Nicira-defined \fBNXT_ROLE\fR OpenFlow vendor extension may be
+useful for this.)
+.PP
If no \fIcontroller\fR is specified, \fBovs\-openflowd\fR attempts to
discover the location of a controller automatically (see below).
.