[ovs-discuss] error message with connection to openflow controller

Ben Pfaff blp at nicira.com
Thu May 26 17:42:33 UTC 2011

On Thu, May 26, 2011 at 10:30:46PM +0500, ahmad numan wrote:
> I setup  OVS on a machine (loaded kernel module, setup ovs-vswitchd and
> bridges etc.)and connect to an out-of-band NOX controller using
> ovs-openflowd. Controller got connected and switch is working correct
> (machines are pinging each other and netperf is also working correctly in
> openflow network). But i got error message after connecting with controller
> such as "attempt to reuse the buffer" in ovs-openflowd terminal . NOX
> controller terminal is also showing error message "received openflow error
> packets for dpid XXXXXXXXX type=1 code=7". Moreover when i tried to manage
> the openflow traffic using "ovs-ofctl" i got error message "fail to delete
> flow" in ovs-openflowd terminal.
> What do these error messages indicate ? is there any error in configuration
> or something else?

"Attempt to reuse buffer" means that the controller has tried to use
the same buffer_id in two or more OpenFlow requests.  That doesn't
work, because the first use of a buffer_id causes the buffer to be
freed so that it can be reused for new packets coming in.

I don't know why "ovs-ofctl" would report that error.  Can you show
the whole ovs-ofctl output?  Add "-vvconn" to the command line to get
more debugging output.

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