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Date:      Mon, 20 Mar 2017 19:41:29 +0100
From:      Harry Schmalzbauer <freebsd@omnilan.de>
To:        Vincenzo Maffione <v.maffione@gmail.com>
Cc:        "freebsd-net@freebsd.org" <freebsd-net@freebsd.org>
Subject:   Re: Are ./valte-ctl and ./bridge friends or competitors?
Message-ID:  <58D02259.9010101@omnilan.de>
In-Reply-To: <CA%2B_eA9hso4AKpFEJCXWHYYz5tbLx4jT2o=3c-3YrWM98ovB8%2BA@mail.gmail.com>
References:  <58CBA727.3040108@omnilan.de> <58CBBF7A.8050604@omnilan.de> <CA%2B_eA9jYxRoi2HPcVjKbifTM43nnHeMQGDmmQvsw5UdXtLmFug@mail.gmail.com> <58CC26CF.5050708@omnilan.de> <CA%2B_eA9j30Shp1QB%2B6UY1YRqsWKRo4xqPvDRnMHT25VQL4QhQ_Q@mail.gmail.com> <58CFA606.7090306@omnilan.de> <CA%2B_eA9hso4AKpFEJCXWHYYz5tbLx4jT2o=3c-3YrWM98ovB8%2BA@mail.gmail.com>

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Bezüglich Vincenzo Maffione's Nachricht vom 20.03.2017 12:50 (localtime):
…
>> So to summarize for newbies exploring netmap(4) world in combination
>> with physical uplinks and virtual interfaces, it's important to do the
>> following uplink NIC configuration (ifconfig(8)):
>> -rxcsum -txcsum -rxcsum6 -txcsum6 -tso -lro promisc
>>
> 
> Exactly. This is mentioned at the very end of netmap(4):
> 
> "netmap does not use features such as checksum offloading, TCP segmentation
> offloading, encryption, VLAN encapsulation/decapsulation, etc.  When using
> netmap to exchange packets with the host stack, make sure to disable these
> features."
> 
> But it is probably a good idea to add these example ifconfig instructions
> somewhere (man page or at least the README in the netmap repo).
> 
> 
>>
>> I guess vlanhwtag, vlanhwfilter and vlanhwtso don't interfere, do they?
>>
> 
> Well, I think they interfere: if you receive a tagged packet and the NIC
> strips the tag and puts it in the packet descriptor, then with netmap you
> will see the untagged packet, and you wouldn't have a way to see the tag.

Hmm, if I connect a vlan child to VALE (once I provided crash info and
someone capable fixed it), it's intentional that the tag was removed.
Otoh, if I attach the parent interface to VALE, stripping isn't done
yet, even if there are children defined for a specific vlan id.  I see
all frames tagged on the parent, at least it was so when I checked that
last time, maybe 2 years ago.  I'm always creating childs with vlan id 1
if I want a interface without taged frames.

Hope I'm not missing something obvious again, I'm about to call it a day
here.

Thanks,

-harry



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