I think I understood you. In a layer 2 triangle the root ports will all be forwarding as it's the STP root. Both devices will be forwarding on the port connected to the root, as they are root ports. This leaves two ports in question, the ports connecting the linux machine to the Cisco router. If you do a show spanning-tree for that interface on the Cisco router you should see a blocked port on the interface connecting it to the Linux box . On the Linux box the port connected to the router will be the designated port for that segment, and will be in forwarding mode. I have a Cisco 2811 and some 2950s, I'll set them up shortly and send in the output, but this conforms to what I'm seeing in STP docs I referenced. This should not be a loop regardless as the port on the Cisco router is blocking, and by it's very nature not forwarding traffic. Is this actually creating a loop?
On Dec 5, 2007 11:09 AM, Troopy . <[EMAIL PROTECTED]> wrote: > > HEllo > > Thanks for your answer but i think you didn't understand me. > > If you have a layer 2 triangle: > 2 (non-root stp) machines (1 Cisco + 1 Linux)have 1 blocking and 1 > forwarding ports > 1 (root stp) machine (Linux) has 2 forwarding ports. > You can try it by yourself, the case study is very simple, you just > need one cisco router and 2 linux. > > > The thing is on the non-root Linux machine, there are 2 forwarding ports > which is NOT normal. This creates a loop. > I think something special has to be changed on Linux ... > > Regards > > TRoopy > > > > > > ---------- Original Message ---------------------------------- > From: "Nick Davey" <[EMAIL PROTECTED]> > Date: Wed, 5 Dec 2007 10:01:40 -0500 > > >>From what I've seen both ends of the redundant link won't be blocking, > one > >will be forwarding on one end, and one will be blocking. If you refer to > the > >original spanning tree diagram drawing in this article: > >http://en.wikipedia.org/wiki/Spanning_tree_protocol diagram 5 you'll see > one > >end of the redundant link is set to designated forwarding, and one is > >blocking. I believe this is what you're describing? I think this is due > to > >spanning tree's requirement that one port on a segment must be chosen for > a > >forwarding, or designated role. Hope that helps. > > > >Nick > > > >On Dec 4, 2007 12:32 PM, Troopy . <[EMAIL PROTECTED]> wrote: > > > >> > >> Hello, > >> > >> I tried to test the spanning tree on Vyatta. > >> > >> There is one problem with Vyatta and more precisely the Linux > plateform. > >> > >> We made a triangle with two Linux/Vyatta router and a Cisco router. > >> One of the Linux is set as the root STP. > >> > >> The Cisco router has a correct behaviour because it has > >> a blocking and forwarding port > >> The root Linux stp has a correct behaviour because it has > >> two forwarding ports > >> The problem is on the non-root stp Linux. It has > >> 2 forwardind ports instead of 1 blocking and one fowarding port. > >> > >> I think something has to be changed on the Linux level but what? > >> > >> Regards > >> > >> TRoopy > >> > >> > >> > >> > >> > >> ______________________________________________________ > >> Désirez vous une adresse éléctronique @suisse.com? > >> Visitez la Suisse virtuelle sur http://www.suisse.com > >> > >> _______________________________________________ > >> Vyatta-users mailing list > >> Vyatta-users@mailman.vyatta.com > >> http://mailman.vyatta.com/mailman/listinfo/vyatta-users > >> > > > > > > > > ______________________________________________________ > Désirez vous une adresse éléctronique @suisse.com? > Visitez la Suisse virtuelle sur http://www.suisse.com > >
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