which spanning-tree to choose

Unanswered Question
Mar 9th, 2009


we search for the best spanning-tree mode available

the whole network is made by 3750 stacks

and with the version we have we can choose between the next modes

(config)#spanning-tree mode ?

mst Multiple spanning tree mode

pvst Per-Vlan spanning tree mode

rapid-pvst Per-Vlan rapid spanning tree mode

is it correct that mst uses a proces per vlan and that rapid-pvst uses even a faster proces per vlan?

I don't really understand the difference between mst an pvst?

thank you

I have this problem too.
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Giuseppe Larosa Mon, 03/09/2009 - 00:36

Hello Bart,

if your network is made all of Cisco switches and all of them support it I would go for rapid-pvst.

PVST uses one old 802.1D instance for each vlan.

Rapid PVST uses one rapid 802.1W instance for each Vlan.

MST 802.1s uses one or more rapid 802.1s instances, each instance can have a group or range of vlans associated with it.

So MST is the most scalable but configuration and planning is more heavy:

all switches need to be configured manually for:

mst mode

mst region name

mst revision number

vlans to instances mapping

if one of the above parameters don't match the two switches think to be in different MST regions.

So if you don't plan to use an high number of vlans I would go for Rapid-PVST

see for PVST and Rapid PVST


for MST


Hope to help


BartV1982 Mon, 03/09/2009 - 03:07

Hi Giuslar,

this was the explanation i was looking for

Thank you for your quick and easy to understand reply


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