From mboxrd@z Thu Jan 1 00:00:00 1970 From: Toshiaki Makita Subject: Re: VLAN ID 0 with priority tagging Date: Fri, 07 Feb 2014 10:08:06 +0900 Message-ID: <52F431F6.9010605@lab.ntt.co.jp> References: <52E05901.6050601@us.ibm.com> <52F4207A.6020408@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit To: Sridhar Samudrala , "netdev@vger.kernel.org" Return-path: Received: from tama50.ecl.ntt.co.jp ([129.60.39.147]:42124 "EHLO tama50.ecl.ntt.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751925AbaBGBIM (ORCPT ); Thu, 6 Feb 2014 20:08:12 -0500 In-Reply-To: <52F4207A.6020408@gmail.com> Sender: netdev-owner@vger.kernel.org List-ID: (2014/02/07 8:53), Sridhar Samudrala wrote: > On 1/22/2014 3:49 PM, Sridhar Samudrala wrote: >> I am trying to send a packet with VLAN ID 0 and non-zero priority. >> >> The VLAN interfaces are created on 2 hosts using >> ip link add link eth1 eth1.0 type vlan id 0 egress-qos-map 0:2 >> >> When i try to send a packet using ping/arping, on the sender side tcpdump >> shows that the VLAN tag is added with ID 0 and priority 2. >> >> However, the receiver is receiving the packet with vlan tag stripped. >> >> I am seeing the same behavior with multiple NICs and also with a >> switch in >> between the 2 hosts or with the 2 hosts connected over loopback cable. >> >> It looks as if the driver on the send side is stripping the tag if >> vlan id is 0. >> Is this correct behavior or a bug? >> Any clues on how to get priority tagging to work with vlan id 0? >> > I sent this note a few weeks back, but i haven't seen any response so far. > > Is priority tagging with VLAN ID 0 not supported or is this a bug? > It looks like the NIC hardware is stripping the VLAN tag if the id is 0 > even when VLAN tag > is added by the software. eth1.0 should be able to send frames tagged with vid 0. Though I don't know whether there are NICs/drivers that strip tag 0, I can send frames with vid 0 (with e1000e). Toshiaki Makita