Hi, all, we still rely on STP in our data centre. Top-of-rack switches are connected to two core switches with Gigabit configured as trunks.
The two core switches have
spanning-tree vlan 1-1005 priority 24576
and
spanning-tree vlan 1-1005 priority 28672
respectively, to make sure the first one is the root with the second as a
backup.
Recently I replaced top-of-rack switch. Switched a WS-C2950T-24 for a
WS-C2960-48TT-L. We have quite a few of those in operation, already
buying them refurbished in the last couple of months.
To my big surprise the new switch that I preconfigured and booted for minimal
downtime, then just moved the cables, put both uplink/trunk ports into the
forwarding state and quickly flooded the console with:
00:26:02: %SW_MATM-4-MACFLAP_NOTIF: Host 001e.f7f6.8f80 in vlan 1 is flapping
between port Gi0/2 and port Gi0/1
00:26:03: %SW_MATM-4-MACFLAP_NOTIF: Host 0000.0c9f.f001 in vlan 1 is flapping
between port Gi0/1 and port Gi0/2
...
What the ...? For the moment I could only solve the problem by unplugging one of
the trunks. I'm not quite sure if I really built a loop that would have brought
my entire
network down, but definitely all servers on that particular switch were
unreachable
- the switch was flooded and completely overloaded.
The software on the new switch is
Cisco IOS Software, C2960 Software (C2960-LANBASEK9-M), Version
15.0(2)SE5, RELEASE SOFTWARE (fc1)
How can I debug this? I have remote access to the misbehaving switch and the old
one it replaced is on my desk. Of course I can provide configuration details,
if needed.
Activating the second uplink port is only possible for short periods of time,
so I'd
like to prepare as well as possible ;-)
Thanks for any hints.
Second with all the fun we have with STP and VTP: we are actively looking into
products
that can replace our layer 2/STP architecture. As far as I know there are
products that can
scale in a mesh and use all active links for traffic.
But when I lookup, say, Brocade's line of switches, we are faced with price
tags ... well.
The 48-Port FE switches cost about a thousand when they were current hardware
and
we bought new. One switch supports 16 servers in our rack. Now we get them for
350
refurbished.
Of course I would happily pay a thousand or two/three for a more modern
architecture
plus GE/10G-uplink instead of FE/GE-uplink. But all products I find seem to be
in the
10k and more range. Which unfortunately is completely out of reach for an
access switch
for us.
Any suggestions on what I should look for?
Kind regards
Patrick
--
punkt.de GmbH * Kaiserallee 13a * 76133 Karlsruhe
Tel. 0721 9109 0 * Fax 0721 9109 100
[email protected] http://www.punkt.de
Gf: Jürgen Egeling AG Mannheim 108285
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