Unanswered Question
May 2nd, 2008
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I am trying to understand all the spanning-tree options but they are difficult to classify.

For all of the following: CST, MST, PVST, PVST +, MISTP, are these options part of the STP or RSTP protocol or both?

Do you know the difference between PVST and PVST +? And I found nothing on CST ou MISTP mode? Do you know some?

Thank you

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Jon Marshall Fri, 05/02/2008 - 03:10
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This is how i understand it.

CST = Common Spanning Tree ie. you have one spanning tree instance for the whole switch network regardless of how many vlans there are.

PVST = Per vlan Spanning Tree. Unlike CST each vlan can run it's own instance of Spanning-tree. PVST is used on ISL trunks.

PVST+ same as PVST but for 802.1q trunks.

RSTP - an improvement on STP that incorporated many of the proprietary features that Cisco had with normal STP ie. uplinkfast, backbonefast.

MST = MISTP - MST uses RSTP but allows you to group a number of vlans to one spannning-tree instance.



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