Thanks Daniel,
That's what I had thought and hoped for - I just felt that the way it was
written made it sound like it just kept on notifying other switches.
I am currently creating a "good-old-dos" application in Turbo Pascal 5.5
that will simulate a set-command based switch. It is not a true simulator
(yet) since it will only tell you if your command was good or not, and what
the result of the command would be. Anyway, I am putting in the commands as
I read them in the book - that way I can practise them on the way.
When I'm done with it, and if it turns out to be any good - I will make it
available for free at my website.
May the rest of your weekend be great,
Ole
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Ole Drews Jensen
Systems Network Manager
CCNA, MCSE, MCP+I
RWR Enterprises, Inc.
[EMAIL PROTECTED]
http://www.insync.net/~drews/ccnp
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-----Original Message-----
From: Daniel Boutet [mailto:[EMAIL PROTECTED]]
Sent: Sunday, September 10, 2000 11:14 AM
To: [EMAIL PROTECTED]
Subject: Re: BCMSN: STP topology changes
Ole
I am not 100% sure but I think that you forgot that it is only meant to age
out the entry faster that the default value of
300 sec or 5 minutes. There are also the Hello msg that tells a switch
which port is actually "live". If you read a little further on page 159
there is mention of timers for bpdu lifetime.
Hope this helps to clarify.
"Ole Drews Jensen" <[EMAIL PROTECTED]> wrote in message
2019FB428FD3D311893700508B71EBFB2C5B6E@RWR_MAIL_SVR">news:2019FB428FD3D311893700508B71EBFB2C5B6E@RWR_MAIL_SVR...
> I am not sure if it's me running on 50% power this Sunday morning (most
> likely), if it's the book that is written like a white house speech, or if
> it's both. Anyway, the reason for this e-mail is that I am reading
something
> that to me doesn't make sense.
>
> For those of you who would like to comment on this, if you have Cisco
Press'
> BCMSN book, I am refereing to "Handling Topology Changes in Spanning Tree"
> on pages 142 and 143.
>
> If you do not have that book, here's a quick description:
>
> Switch A is the ROOT bridge.
>
> Switch B and C are both connected to Switch A.
>
> Switch D is connected to both Switch B and C.
>
> Switch E is connected to Switch D.
>
> Since A and D can see each other through both Switch B and C, the
connection
> between D and C is blocked.
>
> The situation is that Switch D's link to E fails, and Switch D sends a
> notice to Switch A (the root bridge) via Switch B.
>
> The root bridge (Switch A) now sets the topology change in its
configuration
> for a period of time equal to the sum of the fwd delay and max age
> parameters.
>
> According to step 5 (in the book): "A bridge receiving the topology change
> configuration message from the root bridge uses the fwd delay timer to age
> out entries in its address table. This allows it to age out entries faster
> than the normal five-minute default so that stations that are no longer
> available due to the topology change will be aged out faster. It does this
> until it no longer receives topology change configuration messages from
the
> root bridge."
>
> The last line in that quote makes it sound like it keeps receiving
messages
> about the link E being down until it's up again - but what if the Switch E
> never comes up again because it was sold to someone else - will the root
> bridge keep sending messages about it forever??? - I don't think so, but
> that is how I read it.
>
> Can someone please clarify this for me?
>
> Thanks in advance,
>
> Ole
>
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> Ole Drews Jensen
> Systems Network Manager
> CCNA, MCSE, MCP+I
> RWR Enterprises, Inc.
> [EMAIL PROTECTED]
> http://www.insync.net/~drews/ccnp
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
>
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