[c-nsp] Spanning-Tree vs. EoMPLS links in SXI2?

[Mateusz Blaszczyk]

Gert,

maybe you are hitting some old bug as I did long time ago on SXH1, it
was 3C bug...
http://www.gossamer-threads.com/lists/cisco/nsp/81589 ?

Best Regards,

-mat

On 9 March 2010 14:44, Gert Doering <gert at greenie.muc.de> wrote:
> Hi,
>
> maybe a stupid question: are there any issues known with Rapid-PVSTP,
> EoMPLS links, and IOS SXI2?
>
> We just had a "nice" problem due to a broadcast loop which should have
> been broken by STP in the first place, but wasn't - and investigation
> afterwards showed an EoMPLS link that just refuses to forward STP packets.
>
> Here's the setup (simplified):
>
> R1 ==(trunk)== R2 --(MPLS cloud)-- R3 ==(trunk)== R4
>
> the trunk carries about 100+ VLANs, so R2 and R3 are setup to do
> port-mode EoMPLS:
>
> interface GigabitEthernet2/21
>  mtu 1504
>  no ip address
>  udld port disable
>  xconnect 1.2.3.68 11310002 encapsulation mpls
> end
>
>
> Spanning-Tree is active, because of redundancy requirements - the connection
> between R1 and R4 must not fail if R2 or R3 fail.  So there is a second
> trunk, and second EoMPLS link (not shown above).
>
>
> What I can see when I do "show spanning-tree vlan 2800" on R1, it
> claims "this bridge is the root" - and if I ask R4, R4 also claims
> "this bridge is the root".  If I flap the trunk link, I see both sides
> go through the standard STP cycle (blocking/learning/forwarding), but
> no rapid-STP exchange takes place.
>
> We have a number of similar links in our network, and never experienced
> any problem with STP over port-mode EoMPLS (nor with STP over subif
> EoMPLS either).  The only thing that's unique about this particular link
> is that "R3" is running SXI2, and all other (working) EoMPLS things are on
> SXH3a, SXI, or SXI2a.
>
>
> I'll open a TAC case for this, of course, but if one of you has come
> across that and knows which IOS versions are problematic, that would
> be appreciated.
>
> (NB: if one of you has a better suggestion to do "redundant trunks for
> about 100-200 VLANs between R1 and R4" that does not require STP, let
> me know.  "Routed" link redundancy is not possible, as there are devices
> to the left and right of R1 and R4 that need to be in the same L2 domain.
> Depending on link state of R1->R2 is also not good enough, as R2 might
> have some issues leading to end-to-end failure...)
>
> gert
> --
> USENET is *not* the non-clickable part of WWW!
>                                                           //www.muc.de/~gert/
> Gert Doering - Munich, Germany                             gert at greenie.muc.de
> fax: +49-89-35655025                        gert at net.informatik.tu-muenchen.de
>
> _______________________________________________
> cisco-nsp mailing list  cisco-nsp at puck.nether.net
> https://puck.nether.net/mailman/listinfo/cisco-nsp
> archive at http://puck.nether.net/pipermail/cisco-nsp/
>