From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <472600E6.7060203@candelatech.com> Date: Mon, 29 Oct 2007 08:48:54 -0700 From: Ben Greear MIME-Version: 1.0 Subject: Re: [Bridge] Re: Small packets References: <96CF49BD8B56384395D698BA99007FA32D06@exchange.pacwire.local> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit List-Id: Linux Ethernet Bridging List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Andy Gospodarek Cc: bridge@osdl.org, Benny Amorsen Andy Gospodarek wrote: > On 10/29/07, Benny Amorsen wrote: >>>>>>> "LS" == Leigh Sharpe writes: >> LS> Standard e1000 hardware. The packets being bridged contain a VLAN >> LS> tag, which is included in the 60 bytes. >> >> The e1000 has VLAN acceleration. The VLAN tag is sent in a separate >> register. If you do packet capture on the sender, the packet will >> likely look 60 bytes long, even if it is 64 bytes on the wire. >> >> The same thing happens on receive. Packet dumping with VLAN's is a bit >> of a mess in Linux. If you're lucky you can find a card without VLAN >> acceleration to do the packet dump. >> >> >> /Benny >> > > Are these the lengths on the wire or when captured on the host? The > smallest VLAN tagged frame should be 68 bytes IIRC. A tagged frame > that is 64 bytes seems too small. That is not correct per the 802.1Q VLAN RFC, though I don't have the reference handy at the moment. 64 bytes is fine, vlan tagged or otherwise. Thanks, Ben > _______________________________________________ > Bridge mailing list > Bridge@lists.linux-foundation.org > https://lists.linux-foundation.org/mailman/listinfo/bridge -- Ben Greear Candela Technologies Inc http://www.candelatech.com