From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756439AbaHHQeB (ORCPT ); Fri, 8 Aug 2014 12:34:01 -0400 Received: from mail-pa0-f50.google.com ([209.85.220.50]:34214 "EHLO mail-pa0-f50.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756037AbaHHQd7 (ORCPT ); Fri, 8 Aug 2014 12:33:59 -0400 Date: Fri, 8 Aug 2014 09:33:56 -0700 From: Stephen Hemminger To: Zoltan Kiss Cc: David Vrabel , Wei Liu , Ian Campbell , , , Subject: Re: [Xen-devel] [PATCH] xen-netback: Turn off the carrier if the guest is not able to receive Message-ID: <20140808093356.04d7228b@haswell.linuxnetplumber.net> In-Reply-To: <53DFA30E.2000301@citrix.com> References: <1406749849-4356-1-git-send-email-zoltan.kiss@citrix.com> <1406749849-4356-2-git-send-email-zoltan.kiss@citrix.com> <53DF8C24.6030709@citrix.com> <53DFA30E.2000301@citrix.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This idea of bouncing carrier is wrong. If guest is flow blocked you don't want to toggle carrier. That will cause problems because applications that are looking for carrier transistions like routing daemons will be notified. If running a routing daemon this will also lead to link flapping which is very bad and cause lots of other work for peer routing daemons. Carrier is not a suitable flow control mechanism.