[c-nsp] Spanning Tree help sought

[Christopher Gray]

Jon - many thanks.

With the primary WAN router going into A, and the secondary into C - I
assume that the "root bridge" is A and the "backup root bridge" is C.

Everyone has warned me of edge-loops and I have experienced one myself on a
remote site with no on-site IT support and where a contractor plugged two
ends of a very long UTP cable into the same switch.  The resulting mayhem
meant that the remote management system just saw chaos but at least they
were able to disable one of the ports until someone could visit the site to
sort it out.

THANK YOU to everyone who has responded.  The new switches turn up in a
couple of weeks and so I have time to RTFM and create a lab-based ring of
old switches to test the configurations.  I'll even cause a loop and see
what happens

-----Original Message-----
From: Jon Lewis [mailto:jlewis at lewis.org] 
Sent: 15 November 2012 4:37 PM
To: Christopher Gray
Cc: 'Ross Halliday'; cisco-nsp at puck.nether.net
Subject: Re: [c-nsp] Spanning Tree help sought

On Thu, 15 Nov 2012, Christopher Gray wrote:

> On reading your response - and used the links you suggested - I note 
> that I could just leave everything as default and let STP sort itself out.

You could...but you really should dictate which switches are the root bridge
and backup root bridge.  Additionally, do not attempt to disable STP on any
ports unless you really know what you're doing and can guarantee that nobody
who doesn't will ever be able to plug anything into those ports.  Bridge
loops are a major PITA, and quickly overload things to the point that you
may not be able to do anything to troubleshoot other than start physically
unplugging things until you "make it stop".

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