RE: PVST Question

Hey,

It is a bit confusing at times : ) I believe that PVSTP was the original
implementation of having a spanning-tree instance for each VLAN and yes it
was limited to ISL...but then after everybody jumped on the 802.1Q wagon,
Cisco implemented PVSTP+ which was essentially the same thing, but worked
with 802.1Q. What you see on modern day switches is PVSTP+

Again, this can get confusing, so if somebody else has any corrections
please let me know!

Regards,

Joe Astorino
CCIE #24347 (R&S)
Sr. Support Engineer - IPexpert, Inc.
URL: http://www.IPexpert.com
 

-----Original Message-----
From: nobody_at_groupstudy.com [mailto:nobody_at_groupstudy.com] On Behalf Of
walkingwithcisco
Sent: Monday, June 22, 2009 8:07 AM
To: Cisco certification
Subject: PVST Question

Dear Experts,

I come across a question PVST when I'm reading BCMSN. Here is :

PVST requires the use of ISL Trunking Encap between switches. >> That means
we totally cannot use dot1q trunk if we are running PVST. ????

another notable point is (especially for Open Ended Question) :
In networks where PVST and CST coexist, interoperability problems occur.
Each require a different trunking method, so BPDUs are never exchanged
between STP types. >> It will probably come to us as a tricky question. In
real live network, that mean we cannot run CST and PVST together. ?????

Thanks.

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Received on Mon Jun 22 2009 - 08:31:38 ART