Re: [Aoetools-discuss] AoE and Ethernet padding
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From: <de...@we...> - 2008-01-12 09:53:22
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nice find do you also see a relation to this one http://osdir.com/ml/linux.network.b= ridge/2006-03/msg00009.html =3F > -----Urspr=FCngliche Nachricht----- > Von: "Marcelo Messa" <mr...@gm...> > Gesendet: 11.01.08 22:32:15 > An: aoe...@li... > Betreff: [Aoetools-discuss] AoE and Ethernet padding >=20 > Hi, >=20 > Someone knowns the reason that vblade server expect a "padded" =20 > packet (at least 60 bytes long), but aoe module doesnt generate =20 > packets with this minumum size=3F >=20 > vblade -> aoe.c -> aoe function -> "if (n < 60) =20 > continue;" statement >=20 > This code exists since vblade-1, so I suspect that it is to =20 > avoid loopback (lo) interference ("aoe=5Fiflist" is a later =20 > improvement) or some old NIC bug. (someone knows why=3F) >=20 > The point is: padding is a NIC chipset job. And what happens =20 > if we have a "virtual NIC" (where there are no chipset and no =20 > "physical need" to module/fullfill packets to CRC) =3F >=20 > I made tests with Xen and, for example, a AoE drive exported =20 > from Dom0 are not able to be recognized by guests (in same physical =20 > machine). And as I see, the last message from this lists, refering =20 > VMWare strange behavior, are the same case (http://article.gmane.org/=20 > gmane.network.aoe.aoetools.general/603). The reason is that there are =20 > no padding in this communication. >=20 > I posted a message in xen-users list because I think that =20 > they have problems there, but I think that something could be done =20 > here too. >=20 > We have a lot of innovations in virtualization (and much more =20 > to come). As AoE has a minimal 32 bytes lenght packet (or either =20 > 22bytes since it is possible arg=3D0 after header by protocol, but I =20 > did found any real situation to this occur), why not: >=20 > 1) change vblade code to discard packets with len < =20 > 32 (instead of 60) =3F > or > 2) if it is important to vblade the padding, why not =20 > make aoe module do this padding=3F >=20 > Cheers > Marcelo Messa >=20 >=20 > ------------------------------------------------------------------------= - > Check out the new SourceForge.net Marketplace. > It's the best place to buy or sell services for > just about anything Open Source. > http://ad.doubleclick.net/clk;164216239;13503038;w=3Fhttp://sf.net/marketp= lace > =5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F > Aoetools-discuss mailing list > Aoe...@li... > https://lists.sourceforge.net/lists/listinfo/aoetools-discuss >=20 =5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F Jetzt neu! Sch=FCtzen Sie Ihren PC mit McAfee und WEB.DE. 30 Tage kostenlos testen. http://www.pc-sicherheit.web.de/startseite/=3Fmc=3D022220 |