Got a bridge with 4 optical VLAN interfaces, eth1.1, eth1.2, eth1.3 and eth1.4, attached and the builtin STP enabled. eth1 is connected to a "switch" with 4 real interfaces, each real interface maps to one of the above mentioned VLANs. If I loop two or more interfaces by connecting each interface's output to its own input, I get a loop that STP doesn't detect. Looping by connecting an output from one interface to another interface input works fine. Bug or limitation in STP? If limitation, would RSTP help here? Kernel 2.6.25 Jocke
Hi Joakim, I'm not aware if Linux bridge is aware of this. I can tell you that in general, STP has problems when mixed with VLANs. To solve this some extensions have arised: PVST by Cisco, MSTP, an improvement more or less estandarized and PVST+, a new update only available in Cisco environments. In general they run multiple "STP" instances per VLAN or VLAN group. Regards El mi?, 07-05-2008 a las 11:22 +0200, Joakim Tjernlund escribi?:> Got a bridge with 4 optical VLAN interfaces, eth1.1, eth1.2, eth1.3 and > eth1.4, attached and the builtin STP enabled. eth1 is connected to > a "switch" with 4 real interfaces, each real interface maps to one of > the above mentioned VLANs. > > If I loop two or more interfaces by connecting each interface's output > to its own input, I get a loop that STP doesn't detect. > Looping by connecting an output from one interface to another interface > input works fine. > > Bug or limitation in STP? If limitation, would RSTP help here? > > Kernel 2.6.25 > > Jocke > _______________________________________________ > Bridge mailing list > Bridge at lists.linux-foundation.org > https://lists.linux-foundation.org/mailman/listinfo/bridge-- Jaime Nebrera - jnebrera at eneotecnologia.com Consultor TI - ENEO Tecnologia SL Pol. PISA - C/ Manufactura 6, P1, 3B Mairena del Aljarafe - 41927 - Sevilla Telf.- 955 60 11 60 / 619 04 55 18
Joakim Tjernlund <joakim.tjernlund at transmode.se> writes:> If I loop two or more interfaces by connecting each interface's output > to its own input, I get a loop that STP doesn't detect. > Looping by connecting an output from one interface to another interface > input works fine.Do you see BPDU packets come back when you do the loops? tcpdump can probably help. It sounds like the switch is eating your BPDU's. /Benny
On Wed, May 7, 2008 at 9:22 AM, Joakim Tjernlund <joakim.tjernlund at transmode.se> wrote:> Got a bridge with 4 optical VLAN interfaces, eth1.1, eth1.2, eth1.3 and > eth1.4, attached and the builtin STP enabled. eth1 is connected to > a "switch" with 4 real interfaces, each real interface maps to one of > the above mentioned VLANs. > > If I loop two or more interfaces by connecting each interface's output > to its own input, I get a loop that STP doesn't detect. > Looping by connecting an output from one interface to another interface > input works fine. > > Bug or limitation in STP? If limitation, would RSTP help here?Limitation in STP. If a bridge receives one of its own STP packets on the same interface from which it was sent, that indicates a loop elsewhere in the network that disabling an interface locally will not fix, therefore STP takes no action.> > Kernel 2.6.25 > > Jocke > _______________________________________________ > Bridge mailing list > Bridge at lists.linux-foundation.org > https://lists.linux-foundation.org/mailman/listinfo/bridge >