[ovs-discuss] Drops in OVS

[Abhishek Verma]

Thanks Flavio.

I installed very specific flow-rules and checked the counter values. That
way i checked the segment where there were losses.

My question is this:

When i add a flow rule which matches on some source IP, dest IP and i give
a output port as an action, then if i see the packet counter incrementing
then can i be sure that the packet was successfully sent out by OVS?

Is the counter incremented in the ingress pipeline or the egress? That is,
is it possible that the counter was incremented, and then OVS later dropped
it because of some reason?

Thanks, Abhishek

On Thu, Jul 30, 2015 at 6:18 PM, Flavio Leitner <fbl at sysclose.org> wrote:

> On Thu, Jul 30, 2015 at 05:56:29AM +0530, Abhishek Verma wrote:
> > Hi,
> >
> > I have 3 switches connected via OVS like this:
> >
> > R1 -- R2 -- R3
> >
> > I am doing an iperf test using TCP between R1 and R3. R1, R2 and R3 are
> > spread out geographically and i use a VXLAN tunnel to connect them.
> >
> > iperf test shows me considerable packet losses. However, ovs-vsctl get
> > interface stats is showing me zero losses on all the legs.
> >
> > This means that OVS for example on R2 forwarded all the packets that it
> > recieved on the VXLAN tunnel from R1 to R3. Is my assumption correct.
> This
> > means that the packet losses reported by iperf are the packet losses in
> the
> > network and not because of OVS.
> >
> > Besides interface statistics is there any other way to get packet drops
> by
> > OVS?
>
> You might have drops at the NIC level, so check ethtool -S output or
> bad flows  which for some reason is dropping packets too.
>
> fbl
>
>
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