ofp-util: Work on decoding OF1.1 flow_mods.

[openvswitch] / PORTING

diff --git a/PORTING b/PORTING
index a6685d900fec23da16173949a558ab2fe3e645f4..ffde29637e5f33e921fac75f1bf852860993ed9a 100644 (file)
--- a/PORTING
+++ b/PORTING
@@ -245,10 +245,16 @@ ovs_be64 as fixed-width types in network byte order.  Each of the
 latter is equivalent to the one of the former, but the difference in
 name makes the intended use obvious.
 
-ovs-vswitchd is the most sophisticated of ofproto's clients, but
-ofproto can have other clients as well.  test-openflowd, in the
-"tests" directory, is much simpler than ovs-vswitchd.  It may be
-easier to initially bring up test-openflowd as part of a port.
+The default "fail-mode" for Open vSwitch bridges is "standalone",
+meaning that, when the OpenFlow controllers cannot be contacted, Open
+vSwitch acts as a regular MAC-learning switch.  This works well in
+virtualization environments where there is normally just one uplink
+(either a single physical interface or a bond).  In a more general
+environment, it can create loops.  So, if you are porting to a
+general-purpose switch platform, you should consider changing the
+default "fail-mode" to "secure", which does not behave this way.  See
+documentation for the "fail-mode" column in the Bridge table in
+ovs-vswitchd.conf.db(5) for more information.
 
 lib/entropy.c assumes that it can obtain high-quality random number
 seeds at startup by reading from /dev/urandom.  You will need to