isl & dot1q & PVST

Unanswered Question
Feb 1st, 2007


1. Can we have isl & dot1q both configured on a swith on different trunk ports. The traffic from dot1q trunk will go out by trunk port with ISL encap & vice versa..

2. PVST & PVST+ are different, some cisco doc read that if u see 'pvst' in running config of IOS , it means 'pvst+'

plz comment .. any known issues..



I have this problem too.
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Francois Tallet Thu, 02/01/2007 - 10:28

Hi Gaurav,

-1- : yes, that's the default (and only) behavior. ISL is limited to the first 1K vlans though.

-2- PVST+ is just the modified version of PVST that was introduced at the same time of dot1Q encap. There is no real need to make any difference between the two because the user does not have the ability to select one versus the other. Almost any Cisco switch is now running PVST+. Now, the important difference is between PVST and MST modes of operation, not between PVST and PVST+. That's why there is no real need of saying PVST+.




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