spanning tree and vlans

[carl_townshend]

Hi all, can anyone tell me when using pvst on switches, where does the vlan info for each spanning tree instance get carried?

[Sybren.Apiecionek_2]

If you mean STP: I think it is on every link that that vlan is allowed & not pruned

If you mean VTP: I think it is on every switch that is in the same VTP domain. (depending of the mode it will treat VTP packets differently)

[carl_townshend]

I mean, how does that specific vlan know it is in a certain instance ? what info do the switches share, is it purely different bpdu's per vlan ?

[passioncas]

Hi..

For each VLAN , there is a unique BPDU and it contains Bridge ID and Root Bridge ID information about the respective VLAN. VTP is entirely different which carry VLAN membership information about each Swicth Port

Hope to help

Passioncas