Can I run PVST if I am using Dot1Q encapsulation ?
I was going through the documents that says
"Common Spanning Tree
The IEEE 802.1Q standard specifies how VLANs are to be trunked between switches. It also
specifies only a single instance of STP that encompasses all VLANs. This instance is referred to
as the Common Spanning Tree (CST). All CST BPDUs are transmitted over trunk links using the
native VLAN with untagged frames.
Having a single STP for many VLANs simplifies switch configuration and reduces switch CPU
load during STP calculations. However, having only one STP instance can cause limitations, too.
Redundant links between switches will be blocked with no capability for load balancing. Conditions
also can occur that would cause CST to mistakenly enable forwarding on a link that does not
carry a specific VLAN, whereas other links would be blocked.
Per-VLAN Spanning Tree
Cisco has a proprietary version of STP that offers more flexibility than the CST version. Per-VLAN
Spanning Tree (PVST) operates a separate instance of STP for each individual VLAN. This allows
the STP on each VLAN to be configured independently, offering better performance and tuning
for specific conditions. Multiple spanning-trees also make load balancing possible over redundant
links when the links are assigned to different VLANs. One link might forward one set of VLANs,
while another redundant link might forward a different set.
Because of its proprietary nature, PVST requires the use of Cisco Inter-Switch Link (ISL) trunking
encapsulation between switches. In networks where PVST and CST coexist, interoperability
problems occur. Each requires a different trunking method, so BPDUs are never exchanged
between STP types."
But When I am seeing on my Network, I can see multiple Instances running with different BID for different VLAN's though I am using 802.1Q trunk .
Just to further clarify that this is a distribution Switch where we have configured trunks to all my Access Switches with respective Vlan on them. All these have also been tagged with NATIVE.
Thanks for help