It isn't commonly a problem in practice because flows most often start off with a single packet and wait for a return packet before ramping up packet volume. I've been aware of the issue for years, but you are the only other person I ever recall bringing it up on the mailing lists.
Do you have a real situation (not a hypothetical scenario) where you see this causing trouble? On Fri, Apr 27, 2012 at 11:06:29AM +0600, junaid khalid wrote: > Are you planning to solve this problem in near future or do you have any > suggestions to mitigate this problem? > > On Thu, Apr 26, 2012 at 2:37 AM, Ben Pfaff <b...@nicira.com> wrote: > > > On Wed, Apr 25, 2012 at 01:33:56PM -0700, Joji Mtt wrote: > > > I am trying to figure out if there would be a packet order issue with the > > > current version of OVS. Consider a case where a controller has added a > > > forwarding rule for a specific flow (Flow A) and this rule is not yet > > > installed in the DP. In this scenario, it is conceivable that certain > > > (bursty) traffic patterns on Flow A can result in the packets being sent > > > out of order. E.g. consider an initial burst of 5 packets that miss the > > > kernel flow table, followed by several subsequent packets arriving at > > > random intervals. As soon as the userspace processes the flow miss, it > > will > > > install a rule in the kernel. Depending on the relative timing of the > > rule > > > installation, any of these subsequent packets could get switched directly > > > by the kernel before the previous packets that took the slow path could > > get > > > forwarded. I couldn't find any special handling to cover this case. Most > > > likely it is already handled and I am just missing the part where it is > > > done. Could anyone clarify this for me? > > > > Yes, it's possible to get out-of-order packets for this reason. > > _______________________________________________ > > discuss mailing list > > discuss@openvswitch.org > > http://openvswitch.org/mailman/listinfo/discuss > > _______________________________________________ discuss mailing list discuss@openvswitch.org http://openvswitch.org/mailman/listinfo/discuss
