On Fri, May 19, 2017 at 10:57:17AM +0000, Szczerbik, PrzemyslawX wrote: > > > > -----Original Message----- > > From: Ben Pfaff [mailto:[email protected]] > > Sent: Friday, May 19, 2017 4:39 AM > > To: Szczerbik, PrzemyslawX <[email protected]> > > Cc: [email protected] > > Subject: Re: [ovs-dev] [PATCH] ofproto-dpif-ipfix: add support for per-flow > > TCP > > counters > > > > On Thu, May 11, 2017 at 11:13:27AM +0100, Przemyslaw Szczerbik wrote: > > > This patch implements support for per-flow TCP IPFIX counters. It's based > > > on > > RFC > > > 5102, section 5.10. > > > > > > Signed-off-by: Przemyslaw Szczerbik <[email protected]> > > > > Thanks for working on IPFIX! > > > > I suggest folding in an update to NEWS to mention this new feature, > > Sure thing, I can update NEWS file. > > e.g.: > > > > diff --git a/NEWS b/NEWS > > index 7a2b185bbd84..ab2faec02e57 100644 > > --- a/NEWS > > +++ b/NEWS > > @@ -10,7 +10,9 @@ Post-v2.7.0 > > Log level can be changed in a usual OVS way using > > 'ovs-appctl vlog' commands for 'dpdk' module. Lower bound > > still can be configured via extra arguments for DPDK EAL. > > - - IPFIX now provides additional counters for totals since startup. > > + - IPFIX now provides additional counters: > > + * Total counters since metering process startup. > > + * Per-flow TCP flag counters. > > - New support for multiple VLANs (802.1ad or "QinQ"), including a new > > "dot1q-tunnel" port VLAN mode. > > - In ovn-vsctl and vtep-ctl, record UUIDs in commands may now be > > > > However, I am worried about this feature. I suspect that it does not > > report correct statistics. It infers that, if a flow's tcp_flags > > contains a given flag, then that flag has been seen on every packet. > > But this is incorrect: in fact, it only means that the flag has been > > seen on at least one packet. > > Flow represents exact content of the packet that is going to be sampled. > If packet, is it in fact a TCP packet, then tcp_flags member will contain > appropriate values. > I'm assuming that all matched packets had exactly the same flags set, which > really boils down to a single issue - IPFIX counters are based on probability. > > Sampling probability is used to approximate number of matched packets, which > is then used as a baseline for majority of other counters. > For instance, octet_delta_count counter implementation assumes that all > matched packets have the same length. > > I run a few tests on my patch and it worked quite well.
OK, I understand the context now. Thanks for the explanation. I applied this to master. Thank you! _______________________________________________ dev mailing list [email protected] https://mail.openvswitch.org/mailman/listinfo/ovs-dev
