ofproto: Prefer "master" and "other" connections for snooping over "slave".

This makes "ovs-ofctl snoop" and anything else that connects to the
switch's "snoop" socket typically more useful in the presence of multiple
controllers, since the "master" connection is the one with the most
interesting traffic.

Suggested-by: Justin Pettit <jpettit@nicira.com>

1 files changed, 10 insertions, 2 deletions

diff --git a/utilities/ovs-ofctl.8.in b/utilities/ovs-ofctl.8.in
index d84b4819b..8d48d98a3 100644
--- a/utilities/ovs-ofctl.8.in
+++ b/utilities/ovs-ofctl.8.in
@@ -155,8 +155,16 @@ Thus, this command can be used to view OpenFlow protocol activity
 between a switch and its controller.
 .IP
 When a switch has more than one controller configured, only the
-protocol to and from a single controller, chosen arbitrarily by Open
-vSwitch, is given.  If a switch has no controller configured, or if
+traffic to and from a single controller is output.  If none of the
+controllers is configured as a master or a slave (using a Nicira
+extension to OpenFlow), then a controller is chosen arbitrarily among
+them.  If there is a master controller, it is chosen; otherwise, if
+there are any controllers that are not masters or slaves, one is
+chosen arbitrarily; otherwise, a slave controller is chosen
+arbitrarily.  This choice is made once at connection time and does not
+change as controllers reconfigure their roles.
+.IP
+If a switch has no controller configured, or if
 the configured controller is disconnected, no traffic is sent, so
 monitoring will not show any traffic.
 .