From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf1-x443.google.com (mail-pf1-x443.google.com [IPv6:2607:f8b0:4864:20::443]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by lists.bufferbloat.net (Postfix) with ESMTPS id A17E83B29E for ; Fri, 26 Jun 2020 18:01:08 -0400 (EDT) Received: by mail-pf1-x443.google.com with SMTP id j12so5187776pfn.10 for ; Fri, 26 Jun 2020 15:01:08 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=networkplumber-org.20150623.gappssmtp.com; s=20150623; h=date:from:to:cc:subject:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=lxaxMyrU1zNhtGVJmQYInG+3Ux8u7KVzHER9Vu5WtSA=; b=WUAB3OFcFWr/Qundtoha7tOL4LlKlslF33Jo3j3deKUSAi55fCHDTcY4WCe/VWNvQy JEqnEKIed1wocgzJYiv9wTUWFQZHJVRyBlOosWqZwFHoHbtUo9O/jZ4KkgR9DcmvWw4e xF+SrPlVMJuhoppXjCORikTmlr9ukjVsnviJAHcPrNJ75ATaGhrN+/mnZOkYm4uM+ejf EdaQ5crcQLzW1HlwF/fcryce2cBRZXPwdwNW9rD36cOrjqd+dvcImCxbYW+qpCqycDrf Y9nl/ZKLthltRgAnTmdgmRoZOpEKOI0kifRhZKJ5CVatgrFuFzEmAG1L/Wbbh94bLBvd /YRQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=lxaxMyrU1zNhtGVJmQYInG+3Ux8u7KVzHER9Vu5WtSA=; b=EHjoMx7P6bRMUzCfMdeh+bbKnTEBTsOSmIaJpm06y0Z5Gj2QFBnbWa0xHysqtUtYk9 XfKk7fut1+8kQArFN9JVNQ+UT7jugJ8zw44qiYDHcfwpmhNkYdjCjrLi+bA+XErzDV8q /MfDy+tuUUZSY2kDbUIK1wStmy9WpMCcQVyhOwrsbOhXLIsYsbSZu9lVH5THt9AF5XTZ 00nr9K54hCy476RlxeRQvU3a8nbgdsosbn9UKzZ250jBATxYHHMljFB/KWU8Ho+AUhh1 aCRCpY6BeopRERSE5asoy+Xr4gn1y81rHVfXBzdy6SKXrh7xOr6KyLZYe261JG7i22uK qxRQ== X-Gm-Message-State: AOAM530NjAKaSgXriwiMzj1ET1SUIudfpGZ7qmahjKC2HlxTAUUdtpaE oG8kbI2nc3Iz7oROJ1ftVZDlYg== X-Google-Smtp-Source: ABdhPJwJ1vnSzzWMtQio9AJ5Iz/GuTGwDRYr7ySqsk/wFoTr8/YS5IsiG75Sd0BN5mZKr74dyHA1Ug== X-Received: by 2002:a65:4507:: with SMTP id n7mr742674pgq.180.1593208867651; Fri, 26 Jun 2020 15:01:07 -0700 (PDT) Received: from hermes.lan (204-195-22-127.wavecable.com. [204.195.22.127]) by smtp.gmail.com with ESMTPSA id 140sm26547791pfz.154.2020.06.26.15.01.06 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 26 Jun 2020 15:01:07 -0700 (PDT) Date: Fri, 26 Jun 2020 15:00:59 -0700 From: Stephen Hemminger To: Jonathan Morton Cc: Davide Caratti , cake@lists.bufferbloat.net, netdev@vger.kernel.org, David Miller Message-ID: <20200626150059.785647cb@hermes.lan> In-Reply-To: <78C16717-5EB2-49BF-A377-21A9B22662E1@gmail.com> References: <159308610282.190211.9431406149182757758.stgit@toke.dk> <159308610390.190211.17831843954243284203.stgit@toke.dk> <20200625.122945.321093402617646704.davem@davemloft.net> <87k0zuj50u.fsf@toke.dk> <240fc14da96a6212a98dd9ef43b4777a9f28f250.camel@redhat.com> <78C16717-5EB2-49BF-A377-21A9B22662E1@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Subject: Re: [Cake] [PATCH net-next 1/5] sch_cake: fix IP protocol handling in the presence of VLAN tags X-BeenThere: cake@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: Cake - FQ_codel the next generation List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 26 Jun 2020 22:01:08 -0000 On Fri, 26 Jun 2020 16:11:49 +0300 Jonathan Morton wrote: > Toke has already replied, but: > > > Sure, my proposal does not cover the problem of mangling the CE bit inside > > VLAN-tagged packets, i.e. if we should understand if qdiscs should allow > > it or not. > > This is clearly wrong-headed by itself. > > Everything I've heard about VLAN tags thus far indicates that they should be *transparent* to nodes which don't care about them; they determine where the packet goes within the LAN, but not how it behaves. In particular this means that AQM should be able to apply congestion control signals to them in the normal way, by modifying the ECN field of the IP header encapsulated within. > > The most I would entertain is to incorporate a VLAN tag into the hashes that Cake uses to distinguish hosts and/or flows. This would account for the case where two hosts on different VLANs of the same physical network have the same IP address. > > - Jonathan Morton > > _______________________________________________ > Cake mailing list > Cake@lists.bufferbloat.net > https://lists.bufferbloat.net/listinfo/cake The implementation of VLAN's is awkward/flawed. The outer VLAN tag is transparent but the inner VLAN is visible. Similarly the outer VLAN tag doesn't count towards the MTU but inner one does.