Cigesm max VLANs

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Dec 9th, 2009
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The white paper for the cigesm switch says the following: "The number of trunk ports multiplied by the number of VLANs on the switch must be less than or equal to 128."

I guess this means that I can only define 128 vlans on the switch and allow as many over the trunk. I am running pvst on the switch now,would it be any help to migrate to MST? My guess is no, it doesnt matter what kind of STP I run, it will always be constrained by the 128 Vlans?


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tprendergast Thu, 12/10/2009 - 12:14
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MST vs PVST won't have any effect on that constraint. MST has 64 instances of STP with rapid convergence enabled, whereas PVST (or PVST+)  is one STP instance per vlan (so like 4000).

The constraint you see is that the number of trunks * number of vlans <= 128. IE, if you have 2 trunks, and 64 vlans on the switch, then you are in compliance since you only have 128. If you had 4 trunks and 64 vlans configured, 4*64 = 256, and you are violating that constraint.

Hope that helps, rate if it does.


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