[ovs-discuss] permanently saving flow entry in switch table

Ben Pfaff blp at nicira.com
Tue May 31 16:20:46 UTC 2011


On Sun, May 29, 2011 at 10:52:23PM +0500, ahmad numan wrote:
> I want to ask a question that can i permanently save the rules configured
> for openflow in ovs using ovs-ofctl so that i can use switch with same rules
> again without manual configuration?

It's kind of an odd request, one that I don't recall having received
before.  That's because flow tables aren't usually that static.
Usually they would vary as the network changes.

You can probably accomplish something like this by running "ovs-ofctl
dump-flows" and redirecting to a file, editing that file a bit, and
then later using "ovs-ofctl replace-flows" to restore the flow table
contents.

> Problem is when i ran netperf on two machines connected through OVS
> configured as OpenFlow switch, the switch disconnected form controller and
> when netperf finished the switch reconnected automatically. This happens
> every time when i run netperf. Once the switch is disconnected form
> controller i have to manually enter flows to switch rules again to make them
> effective. I don't know why does switch disconnect form controller whenever
> nerperf is initialized? 

This shouldn't happen.  If it does, it shouldn't clear the flow
table.  Only changing the controller, restarting the switch, or a few
other operations should clear the flow table.

Are you running ovs-vswitchd (or ovs-openflowd) with --monitor?  If
so, it's possible that something is crashing the switch.  Then, when
it automatically restarts, it has an empty flow table.  Look in the
logs for messages about crashes.

> Secondly ove-ofctl updates dp0.mgmt for each entry.

I don't know what you mean by that.



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