Thanks for the help chaps.
Unfortunately out IT network was down yesterday and was unable to read your
suggestions. I did however fond the fault.
The root of each Vlan is not statically defined, but this was not the
problem. I simply checked the duplex and negotiation state of each GE port
ensuring all were aligned with their point-to-point neighbour, and
systematically shut and reopened each link. This gave me somewhere to start
from. Another key thing was the number of STP sessions. There are some 150
Vlans visible to the VTP domain, however only four of them were needed
trunked through these trunks. I used the no spanning-tree vlan command to
disable STP sessions on all unnecessary VLANs, this reduced the CPU load
allowing for quicker STP route convergence. We also use the switchport trunk
allow vlan command to ensure only needed vlans is bridged through each
trunk.
In conclusion I think we were encountering the problems due to a combination
of problems, simply made worse by a lack of available CPU time.
Once again thanks for your support.
Regards
Jonathan Desmarais
jon99@uk.colt.net
\C/\O/\L/\T/
V V V V
> -----Original Message-----
> From: Desmarais, Jonathan [mailto:JDesmarais@colt-telecom.com]
> Sent: 13 September 2000 10:35
> To: 'cisco-nsp@puck.nether.net'
> Subject: [nsp] [nsp] 3500 XL Spanning Tree problem
>
>
> I have three 3500XL's connected together in a triangle using GigE.
> The trunks are ISL but all stp interfaces are forwarding, where I am
> sure one in the triangular network should be blocking. Hence one of
> the switches is having to relearn the 4 Vlans related to the network
> every few seconds. This is causing some performance issues.
> Any Idea's?
>
> Regards
>
> Jonathan Desmarais
> jon99@uk.colt.net
> \C/\O/\L/\T/
> V V V V
>
>
>
>
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Registered in England No. 2452736
Registered Office: Bishopsgate Court, 4 Norton Folgate, London E1 6DQ
Tel. 020 7390 3900
This message is subject to and does not create or vary any contractual
relationship between COLT Telecommunications, its subsidiaries or
affiliates ("COLT") and you. Internet communications are not secure
and therefore COLT does not accept legal responsibility for the
contents of this message. Any view or opinions expressed are those of
the author. The message is intended for the addressee only and its
contents and any attached files are strictly confidential. If you have
received it in error, please telephone the number above. Thank you.
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