Why is MSTP needed?

Question

Network administration

Per-VLAN Spanning Tree (not necessarily cisco, but not MSTP either) - vlans without STP instances configured for them form a ring and PSVT is configured for all vlans?

Answer 1

To more efficiently build STP trees within this redundant topology by getting rid of the vlan-instance pairwise binding ; the MSTI/IST/CST/CIST set addresses scalability issues a bit .
Of course they loop and yes, for everyone.

Answer 2

Are we talking about PSVT or MSTP?
PSVT creates its own stp tree for each vlan. Further, at will, we can set our own weights on each tree,
and this gives very great opportunities to manage traffic in theory.
MSTP creates domains to which we add vlanes. Each domain is a separate stp tree. Each domain can have its own weights, and this also gives some flexibility in traffic management.