Hello Adam,
With some luck I can give you some advice.
Am 28.12.2012 16:00, Baack, Adam wrote:
Disclaimer: We are mostly server guys here and know enough switching to be
dangerous. We know very little about spanning tree, etc.
We're implementing our phase 1 of our Enterasys replacement and have been
installing B5 stacks in all of our headquarter IDFs. They are connecting back
to a Cisco 6509 (Sup 2).
We just started having problems where the 6509 would err-disable the LACP lag
between the 6509 and the IDFs. The lag is set for trunking. In the terminal
of the 6509 it shows channel mismatch error. We spoke with GTAC and they said
something about the B5 stacks not participating in spanning tree and the 6509
doesn't know what to do so it disables it.
We are familiar with this situation. We are having Cat6500 as well and
Enterasys E1/C2/C3/C5/G3 and DFE as layer 2 switches. On the other have
we are having different types of Catalyst switches, too.
On the Cat6500 you should configure:
no spanning-tree etherchannel guard misconfig
This helps against some internal checks disabling port-channels etc.
You have configured LACP on Enterasys? What is the proper config on Cat6500?
On Enterasys you should use "set port protected" against loops during
setup phase of LACP/Port-channel. On Cat6500 there should be a similiar
command "port-channel standalone-disable", which have not tested so long.
Also, some of our IDFs have another Cisco switch farther down... example: 6509
--> B5 Stack --> Cisco 3750. The 3750 is also trunking. These setups seem to
be the ones with problems.
This is a crazy situation. We do not have any concept for this right
now. My suggestion: Go to mst on *all* Cisco switches (including Cat6500).
GTAC suggested possibly moving from PVST to RSTP so all of our spanning-tree is
the same. Unfortunately I'm not exactly sure how we would do that or if that's
the solution for us.
Well, that's Cisco and spanning tree :-(
On Cat6500 you have three choices:
(config)#spanning-tree mode ?
mst Multiple spanning tree mode
pvst Per-Vlan spanning tree mode
rapid-pvst Per-Vlan rapid spanning tree mode
mst is IEEE 802.1s (Multiple Instance STP)
The other two ate Cisco proprietary. Enterasys will not be able to
understand the proprietary protocol and will forward the frames as
regular multicasts. This results in a break of spanning tree in an Cisco
cloud and a Enterasys cloud, which partially overlaps. Be award of this
and of possible results.
With Cisco in proprietary spanning tree mode Cisco will ignore
IEEE-STP-BPDUs - which is crazy, too.
I hope I could give you some advice. In case of any questions please
don't hesitate in contacting me
Kind regards and a Happy New Year
Reinhard
--
Karlsruhe Institute of Technology (KIT)
Steinbuch Centre for Computing (SCC)
Dipl.-Ing. Reinhard Strebler
Head of Department Networking und Telecommunikation (NET)
Kaiserstraße 12
76131 Karlsruhe
Phone: +49 721 608-42068/29046
Fax: +49 721 32550
E-Mail: reinhard.streb...@kit.edu
www.scc.kit.edu
KIT - University of the State of Baden-Württemberg and
National Research Center of the Helmholtz Association
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