[ovs-dev] [PATCH v3] ofproto-collectors: Windows - Trigger an ARP request before sending IPFIX packet

Ben Pfaff blp at ovn.org
Wed May 23 20:19:44 UTC 2018


On Fri, May 18, 2018 at 03:16:43PM -0700, Sairam Venugopal wrote:
> IPFIX templates and flow packets are silently dropped when a corresponding
> ARP entry is missing for the Collector. The fix is to explicitly trigger an
> ARP request before sending UDP packets to the collector.
> 
> Making changes in Windows to maintain the destination IP address as part
> of the Collector Structure. Since the SendARP is a blocking call, we do
> not necessarily need to check for a response before sending the IPFIX
> packets. Keeping the fix specific to Windows since this behavior cannot be
> reproduced in Linux.

When you say that SendARP is a blocking call, do you mean that it sends
a packet and then waits for a response?  That will delay everything else
happening in the OVS main thread for an arbitrary amount of time.
Usually this is not acceptable.


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