secchan: Document --rate-limit and --burst-limit options in manpage.

Fixes bug #674.

diff --git a/secchan/secchan.8.in b/secchan/secchan.8.in
index 95e47e9cbdec55ae95dddf88f8bbc6f67c6be3fc..18d1ef3eb9c8299abc656a39063c8d9fc4567dbf 100644 (file)
--- a/secchan/secchan.8.in
+++ b/secchan/secchan.8.in
@@ -371,6 +371,34 @@ The default will change to \fB--stp\fR at some point in the future.
 When flows end on the switch, send NetFlow v5 messages to
 \fIhost\fR on UDP \fIport\fR.
 
+.SS "Rate-Limiting Options"
+
+These options configure how the switch applies a ``token bucket'' to
+limit the rate at which packets in unknown flows are forwarded to an
+OpenFlow controller for flow-setup processing.  This feature prevents
+a single OpenFlow switch from overwhelming a controller.
+
+.TP
+\fB--rate-limit\fR[\fB=\fIrate\fR]
+.
+Limits the maximum rate at which packets will be forwarded to the
+OpenFlow controller to \fIrate\fR packets per second.  If \fIrate\fR
+is not specified then the default of 1,000 packets per second is used.
+
+If \fB--rate-limit\fR is not used, then the switch does not limit the
+rate at which packets are forwarded to the controller.
+
+.TP
+\fB--burst-limit=\fIburst\fR
+.
+Sets the maximum number of unused packet credits that the switch will
+allow to accumulate during time in which no packets are being
+forwarded to the OpenFlow controller to \fIburst\fR (measured in
+packets).  The default \fIburst\fR is one-quarter of the \fIrate\fR
+specified on \fB--rate-limit\fR.
+
+This option takes effect only when \fB--rate-limit\fR is also specified.
+
 .SS "Remote Command Execution Options"
 
 .TP