meta-flow: Correctly set destination MAC in mf_set_flow_value().

[sliver-openvswitch.git] / DESIGN

diff --git a/DESIGN b/DESIGN
index 2e3fced..c53a8ea 100644 (file)
--- a/DESIGN
+++ b/DESIGN
@@ -9,6 +9,38 @@ successful deployment.  The end of this document contains contact
 information that can be used to let us know how we can make Open vSwitch
 more generally useful.
 
 information that can be used to let us know how we can make Open vSwitch
 more generally useful.
 

+OpenFlow
+========
+
+The OpenFlow 1.0 specification requires the output port of the OFPAT_ENQUEUE
+action to "refer to a valid physical port (i.e. < OFPP_MAX) or OFPP_IN_PORT".
+Although OFPP_LOCAL is not less than OFPP_MAX, it is an 'internal' port which
+can have QoS applied to it in Linux.  Since we allow the OFPAT_ENQUEUE to apply
+to 'internal' ports whose port numbers are less than OFPP_MAX, we interpret
+OFPP_LOCAL as a physical port and support OFPAT_ENQUEUE on it as well.
+
+
+Multiple Table Support
+======================
+
+OpenFlow 1.0 has only rudimentary support for multiple flow tables.
+Notably, OpenFlow 1.0 does not allow the controller to specify the
+flow table to which a flow is to be added.  Open vSwitch adds an
+extension for this purpose, which is enabled on a per-OpenFlow
+connection basis using the NXT_FLOW_MOD_TABLE_ID message.  When the
+extension is enabled, the upper 8 bits of the 'command' member in an
+OFPT_FLOW_MOD or NXT_FLOW_MOD message designates the table to which a
+flow is to be added.
+
+The Open vSwitch software switch implementation offers 255 flow
+tables.  On packet ingress, only the first flow table (table 0) is
+searched, and the contents of the remaining tables are not considered
+in any way.  Tables other than table 0 only come into play when an
+NXAST_RESUBMIT_TABLE action specifies another table to search.
+
+Tables 128 and above are reserved for use by the switch itself.
+Controllers should use only tables 0 through 127.
+

 
 IPv6
 ====
 
 IPv6
 ====