From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <4822EE5C.8030404@sysnetsistemi.it> Date: Thu, 08 May 2008 14:13:16 +0200 From: Francesco Dolcini MIME-Version: 1.0 References: <1210152122.32216.95.camel@gentoo-jocke.transmode.se> <2e59e6970805071916r701987fdx49bab341420ba2d@mail.gmail.com> <1210233718.32216.121.camel@gentoo-jocke.transmode.se> <4822C20B.3050303@sysnetsistemi.it> <1210240896.32216.146.camel@gentoo-jocke.transmode.se> In-Reply-To: <1210240896.32216.146.camel@gentoo-jocke.transmode.se> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Bridge] STP bug, loop not detetcted List-Id: Linux Ethernet Bridging List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Joakim Tjernlund , bridge@lists.linux-foundation.org Joakim Tjernlund wrote: > On Thu, 2008-05-08 at 11:04 +0200, Francesco Dolcini wrote: >> cisco and others solved this kind of problem using proprietary >> unidirectional link detection protocols (see cisco informational rfc >> 5171 for example). No standard exists as far as I know (BFD rfc does not >> consider the layer 2 case). > > Are these proprietary unidirectional link detection protocols the only > way to solve the problem? spanning tree protocol, in the various IEEE incarnation (802.1D, 802.1Q) and cisco (PVSTP) does not handle this problem, so an external mechanism is needed. > Would STP break if the interface was set to "non forwarding" in this > case until the bridge stops seeing its own STP messages? At least this will not solve the more general problem of a unidirectional link (rx working and tx broken).