From mboxrd@z Thu Jan 1 00:00:00 1970 From: Johannes Berg Subject: Re: wireless vs. alignment requirements Date: Sun, 25 Nov 2007 18:04:17 +0100 Message-ID: <1196010257.4149.234.camel@johannes.berg> References: <1195893216.4149.186.camel@johannes.berg> <20071124133200.GA27531@gondor.apana.org.au> <1195912176.4149.194.camel@johannes.berg> <20071124141319.GA27819@gondor.apana.org.au> <1195938799.4149.197.camel@johannes.berg> <20071125014446.GA32104@gondor.apana.org.au> <1195988428.4149.225.camel@johannes.berg> <20071125112251.GA10039@gondor.apana.org.au> <1195998864.4149.229.camel@johannes.berg> <20071125140121.GA12665@gondor.apana.org.au> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="=-x97m9NRiaMTqgg2izU1L" Cc: dsd@gentoo.org, davem@davemloft.net, netdev@vger.kernel.org, linux-wireless@vger.kernel.org To: Herbert Xu Return-path: Received: from crystal.sipsolutions.net ([195.210.38.204]:57343 "EHLO sipsolutions.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752273AbXKYREm (ORCPT ); Sun, 25 Nov 2007 12:04:42 -0500 In-Reply-To: <20071125140121.GA12665@gondor.apana.org.au> Sender: netdev-owner@vger.kernel.org List-Id: netdev.vger.kernel.org --=-x97m9NRiaMTqgg2izU1L Content-Type: text/plain Content-Transfer-Encoding: quoted-printable > > Hmm. I don't think so. Take an AP for example. It gets a lot of packets > > from stations. Now, if you're not QoS capable then all is well. But i > > you are and some stations are as well then all those stations send QoS > > packets (+2 bytes). Or take an AP connected via wireless (WPS), WPS has > > +6 bytes so I get all incoming upstream traffic with such unaligned > > headers. >=20 > The question is does this actually change all the time. Let's > say you took a random sample of a second worth of IP packets > over wireless, what proportion of them are going to have the > same hardware header length modulo 4? I'd think that totally depends on the traffic. If you have a non-QoS AP with WPS upstream connection, then the traffic to stations will be four-byte aligned while the WPS upstream will be at a 2-byte-mod-4 boundary. And you'll have all packets from stations come in aligned and all response packets from wherever come in as WPS. johannes --=-x97m9NRiaMTqgg2izU1L Content-Type: application/pgp-signature; name=signature.asc Content-Description: This is a digitally signed message part -----BEGIN PGP SIGNATURE----- Comment: Johannes Berg (powerbook) iQIVAwUAR0mrEKVg1VMiehFYAQIFAA//UXB0E0PGaYxne15/l4wYiHE6+pQyTQtV t57rgJBwPgN18l/PmWCn5EMv+0h0DlF1MRMA3dUusUy4b7MVoUdVF1YX8qoEtfEI UP/whJNH6nYzZGH0bpiQSCi3CQ+kvb1NEkkxotxPDc50TEkQNHoNYKhbK+pD2zCn ll2aIAOVtse9EyXNOeM6qe35EisS+GSP5R1oDX2aHUAkJMRly6lO0AtFjVI2LuWu PcUHkSOH1H6Ow5Tj99yvMM1/GJKOh5AUJAwhgIGdGRfDmdsMVAdhUaWbJE19uVJE y7GuwGsreBewoE2DcicQ6asY4f3a9cOy4L5SnxxOJRjH9wNw7/L347Zi2fmlBFvX PL0+VvkvznlERe3tEe/yzn0/SbTzYViNQrNfgYzgWThu1dwU2y9hRau4fuTufS0p aHDDIinfQfsr5+Ss4NiAAjC4YsOshRbh5FEQUNLPG96gG0Gyyu/0lgrZjZjQYOZA OYGC0DiKZ63Z0daVSDbzVv7BnTUt4EN6DzEZiFhrGl00G1Oyx0sqbacH5wzn7zzG WjAh3cZGoX5WJObEmRxYcpm4mIoReyKh0rOFX9z/Ubt2n1xLYKeR2abOTKGPGuJg pY0YppdHhxP8MfSopIzzExQmQl3311h3wfRc81txXhNrEZFBDg1goauODT2v3gPL k8SBopTpMcI= =T5Up -----END PGP SIGNATURE----- --=-x97m9NRiaMTqgg2izU1L--