From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Hemminger Subject: Re: bridge interface initial carrier state Date: Mon, 11 Feb 2013 13:59:30 -0800 Message-ID: <20130211135930.4cdad83c@nehalam.linuxnetplumber.net> References: <1360612915.8633.6.camel@dcbw.foobar.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org To: Dan Williams Return-path: Received: from mail-da0-f52.google.com ([209.85.210.52]:64774 "EHLO mail-da0-f52.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932691Ab3BKV7p (ORCPT ); Mon, 11 Feb 2013 16:59:45 -0500 Received: by mail-da0-f52.google.com with SMTP id f10so2861783dak.11 for ; Mon, 11 Feb 2013 13:59:44 -0800 (PST) In-Reply-To: <1360612915.8633.6.camel@dcbw.foobar.com> Sender: netdev-owner@vger.kernel.org List-ID: On Mon, 11 Feb 2013 14:01:55 -0600 Dan Williams wrote: > Hi, > > I'm wondering if the initial carrier state of 'on' is intentional for a > bridge without ports; immediately after adding ports, the carrier is > recalculated and depends on the combined state of each port's carrier > and STP forwarding state. So a userspace program attempting to decide > whether the bridge was usable or not has to look at both (a) how many > ports are available and (b) bridge carrier state, instead of just > looking at the bridge carrier state. > > Dan Perhaps a future enhancement of bridge would be to use operstate flags to indicate lower layer down if there are no ports.