From: jamal <hadi@cyberus.ca>
To: Emil Micek <emil.micek@tkrjasek.cz>
Cc: "auke-jan.h.kok@intel.com" <auke-jan.h.kok@intel.com>,
netdev mailing list <netdev@vger.kernel.org>,
Ben Greear <greearb@candelatech.com>
Subject: Re: change the way e1000 is handling short VLAN frames
Date: Fri, 21 Sep 2007 09:37:21 -0400 [thread overview]
Message-ID: <1190381841.4231.10.camel@localhost> (raw)
In-Reply-To: <1190379015.3551.57.camel@magi.nadr>
On Fri, 2007-21-09 at 14:50 +0200, Emil Micek wrote:
> On Fri, 2007-09-21 at 07:59 -0400, jamal wrote:
> > Which would make it a bug. AFAIK, the minimum VLAN tagged packet going
> > out is 68 bytes.
> Are you sure about this?
This is what i have always seen. Double checked with google and she gave
me many a url, example:
http://www.cisco.com/warp/public/473/741_4.html
I think you can pretty much trust cisco on something as basic as this.
Also:
http://www.techfest.com/networking/lan/ethernet2.htm
> We did some extensive testing capturing VLAN
> frames going out of our Intel PRO/1000 MT Dual Port Server Adapter
> (82571EB chipset) and we definitely captured VLAN frames shorter then 68
> bytes. Here is text dump of such frame:
> http://www.tkrjasek.cz/mie/cmts_tests/between_linux_and_cmts.txt
Do you have access to another NIC? a tg3 based one will be good to test
for hardware level tagging.
> (note that wireshark captures the frames without 4 bytes FCS (frame
> check sequence) so the above packet is in fact 66 bytes long).
>
> What is the right behaviour according to specification? In iee802.3,
> minFrameSize is 64bytes. I've never seen any document which'd say that
> VLAN frames should be 68 bytes minimum.
Refer to above.
> Now i'm little confused by your reply, becaouse you write, that VLAN
> frames generated by e1000 should be 68 bytes minimum, which contradicts
> witch our observations.
Miscommunication ;-> I said the packets going out should be 68B
otherwise it is a bug. if e1000 is sending 64B out, it is a bug.
I think any other NIC that doesnt do hardware based vlan tags would be
good to try as well because it uses the software stack to do the
tagging.
cheers,
jamal
next prev parent reply other threads:[~2007-09-21 13:37 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-09-21 7:31 change the way e1000 is handling short VLAN frames Emil Micek
2007-09-21 11:59 ` jamal
2007-09-21 12:50 ` Emil Micek
2007-09-21 13:37 ` jamal [this message]
2007-09-21 13:46 ` jamal
2007-09-21 14:27 ` Francesco Fondelli
2007-09-21 15:43 ` Ben Greear
2007-09-21 21:12 ` jamal
2007-09-21 21:18 ` Ben Greear
2007-09-21 21:21 ` Kok, Auke
2007-09-21 21:29 ` jamal
2007-09-21 21:34 ` Kok, Auke
2007-09-21 21:43 ` jamal
2007-09-21 22:02 ` Chris Leech
2007-09-24 8:40 ` Emil Micek
2007-09-21 21:27 ` Chris Leech
2007-09-21 21:36 ` jamal
2007-09-21 17:05 ` Brandeburg, Jesse
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