Pvstp

burbankmarc

Ok, so I'm a little confused. My self-study guide seems to be slim on the details.

So on switches using PVSTP do the VLANs have to be the same on all switches? If so, how does pvstp tell each switch which vlan the BPDU is for (on access ports)?

I'm experimenting right now, and it looks like the VLANs have to match on the switches. This isn't a huge deal on smaller networks, or on networks using VTP. Just looking for some clarification.

Thanks.

dtlokee

PVST+ works in conjuction with the extended system ID where the 4 most significant bits are the priority, and the lower 12 bits are the VLAN ID. So the 16 bit priority field in the BPDU carries both values.

burbankmarc

Ok, thanks. That makes sense now.