Problem with receiving packets right after remote-interface is up

[M. V.]

Thank you guys for your answers.

On Sat, Sep 5, 2015 at 2:44 PM, Luigi Rizzo <rizzo at iet.unipi.it> wrote:
> You may be able to avoid the issue if you avoid autonegotiation
> and manually set the media type, speed and duplex.

On Sun, 9/6/15, Artem Belevich <artemb at gmail.com> wrote:
> While you can indeed set speed/duplex manually, you will
> also need to make sure both have have proper clock 
> master/slave selection  which is normally done via autonegotiation.
> ...

I continued tests today based on what you said about auto-negotiation might cause the problem.

A thing I found out today was that, even if I put about 3 seconds (or less) delay between "up"ing interface of sender, and sending packets, packet-drop would occur. but if I put 4 seconds delay or more between bringing link up and sending, no drop will occur.

About disabling auto-negotiation and media options:
My interfaces didn't support master/slave option. I changed interface media to both "1000BASET" and "100BASETX" instead of auto, but problem was still there. but interestingly, when I changed receiver's media to "10BASET" (other side was still auto) no packet-drop occurred (even when I removed the delay between bringing up interface and sending packets).

I checked e1000 and em driver codes to find out what is driver doing differently when we set media to 10BASET that makes my tests succeed, but found nothing. Any ideas?

On Sun, 9/6/15, Artem Belevich <artemb at gmail.com> wrote:
> It sounds to me like the problem is with your test setup. If
> your test requires no packet drops, then it implicitly
> assumes having established link and sending the packets
> right after the interface 

Unfortunately we can't change test setup. Spirent Test-Center device runs the tests and gives up the detailed result about what happened, and these drops cause most tests to FAIL at the beginning and doesn't continue.

Thank you.