This version of the specification does not reflect the current checked in
version of OpenFlow. Checkins that follow should bring them in-line. The
TeX version of the spec was produced by Brandon Heller.
Fixes a problem that a port that is disabled via "ifconfig down" does
not come back up properly when it is brought back up again with "ifconfig
up", if STP is enabled.
An STP advertisement is sent after every expiry of the hello timer, so
this reduces STP advertisements to once every 2 seconds.
Once a second seemed like too often.
Suggested by Justin.
This new OpenFlow message format provides a cleaner interface and greater
detail and control over ports. It is now possible to see what features
the switch's port is currently configured as having, what it's advertising,
and what it's capable of handling. It is also possible to return the
features advertised by the port's peer.
802.1D Spanning Tree Protocol supports a maximum of 255 ports per bridge,
but OpenFlow supported 256, so 1 port had to not implement STP. This
gets rid of the problem by reducing the maximum number of ports to 255.
To report on link status and whether a port is administratively enabled or
disabled, the reference switches poll. This change uses the Linux kernel's
device notification system, so that polling isn't necessary.
The kernel datapath was claiming that it implements STP, which is untrue.
In fact, the secchan implements STP, so if the secchan was not running
the STP support did not work. Thus, "controller nl:0" would do the
wrong thing.
This makes the secchan edit the responses from the datapath to claim
STP support.
This cleans up the handling of modifying existing flows. There now exists
OFPFC_MODIFY and OFPFC_MODIFY_STRICT commands, which have the same matching
characteristics to their OFPFC_DELETE* counterparts. When adding a flow that
already exists, the counters and timers are now reset (ie, its treated as a
new flow). This commit also adds the "--strict" option to dpctl to allow
strict matching for "mod-flows" and "del-flows".
The "port watcher" in secchan was not keeping track of updates to port
flags by the controller, which caused some combinations of secchan
and controller to not turn on ports when the STP state otherwise should
have done so.
Thanks to Justin for reporting the problem.
A recent change (696db2) modified the way stats were being sent over the
netlink socket. Unfortunately, the responder set the transaction id to the
type, which caused the requestor to ignore the repsone.
Ben Pfaff
Justin Pettit