> -----Original Message----- > From: Stephen Hemminger [mailto:shemminger@xxxxxxxxxx] > Sent: den 12 maj 2008 19:50 > To: joakim.tjernlund@xxxxxxxxxxxx > Cc: bridge@xxxxxxxxxxxxxxxxxxxxxxxxxx; Francesco Dolcini > Subject: Re: STP bug, loop not detetcted > > On Mon, 12 May 2008 11:37:45 +0200 > Joakim Tjernlund <joakim.tjernlund@xxxxxxxxxxxx> wrote: > > > > > On Thu, 2008-05-08 at 14:58 +0200, Joakim Tjernlund wrote: > > > On Thu, 2008-05-08 at 14:13 +0200, Francesco Dolcini wrote: > > > > 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. > > > > > > Do they explicitly ban it? Otherwise I don't see why not the kernel STP > > > can be enchanted. You could even view it as an external mechanism. > > > > > > > > > > > > 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). > > > > > > hmm, if TX is broken there won't be a loop anyway? > > > > > > Anyhow, even if my proposed change doesn't solve all cases it seems like > > > a useful, very simple, ad don to STP. I am just concerned that it can > > > break some other aspect of STP. So far it seems OK. > > > > > > What is the bridge maintainers view on this? > > > > Stephen, whats is your view about extending the bridge code according to > > above? Also, after looking at the bride code I don't see where this > > should be added, I must be getting old :( > > > > Jocke > > If you want to make STP vlan aware, then fine, a good place to start > is getting a version of new RSTP and making it vlan aware. No, that is not what I meant, forget about VLAN just consider what happens if you loop 2 or more interfaces which is connected to the same bridge. The loop is such that each TX is connected to its own RX. Jocke _______________________________________________ Bridge mailing list Bridge@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/bridge
