Re: bpdu-filter question

For documentation, I would suggest to stay with the docs related to the
product you are working on. There are some differences.

i hope you do not mind this response, but ...

I would suggest to do the lab test another time; it would be a pity for me
to spit out the answer before asking you to check this test again. A good
command (just found tonight when labbing this with you) is this command:

"show spanning-tree interface g0/20 detail"

Look under this command for BPDUs sent and received. I actually found this
question to be interesting because it challenged me in my understanding of
STP as well.

Which switch sends and which switch will respond to BPDUs? Keep this in
mind when you do this test again and you are watching the bpdu counters.

Also, try the bpdufilter command with and without bdpuguard. I believe this
will also show some interesting behavior.

In my lab, I have one switch configured with trunking and the other side
configured for dynamic desirable. If you feel so inclined, try this again
and of course ask questions! We all learn from you ... also, there are some
pretty smart folks on this list (not me ... I am a bear of little brain)

Take care and HTH,

Andrew

On Wed, Nov 4, 2009 at 10:23 PM, <Keegan.Holley_at_sungard.com> wrote:

> GS,
>
> I recently watched a recorded bootcamp that stated that bpdu filter will
> revert back to the default spanning tree behavior if it sees a bpdu. They
> also say should be enabled on port fast ports to avoid loops. I seem to
> have found conflicting documentation on cisco.com one page states that the
> bpdu's are blocked constantly and the other pretty much agrees with the
> vendor. I tried this on a 3550 running 12.2(40) see2 and bpdu's were
> blocked no matter what. Did this change across code releases/platforms or
> are they just wrong?
>
>
> Heads:
>
> http://www.cisco.com/en/US/docs/switches/lan/catalyst3560/software/release/12.2_44_se/configuration/guide/swstpopt.html#wp1033638
>
> tails:
>
> http://www.cisco.com/en/US/docs/switches/lan/catalyst4000/7.4/configuration/guide/stp_enha.html
>
>
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-- 
Andrew Lee Lissitz
all.from.nj_at_gmail.com
Blogs and organic groups at http://www.ccie.net