STP.RSTP and PSTP

STP(Spanning-tree Protocol): Layer 2 protocol used in LAN enviroment to

avoid:

Broadcast Storms
Mac-Table Inestability
Multiples copies of frames.

And it is defined in 802.1d Standard.

RSTP(Rapid Spanning Tree Protocol-802.1w Standard): it is the enhanced protocol of STP,

the main caracteristic of this one is Faster than STP (it converge in less than 6 seconds).

PVST+ (Per Vlan Spanning Tree Plus) : This feature (by cisco) is used to create an instace of

STP for each VLAN. e.g.

If you have a switch with 3 vlans you will have a 3 instances of VLANs that you could
modify the parameters (like to make root bridge for a specific VLAN) independiently
accord to your design goals.

MIST(Multiple Instances of Spaning Tree-802.1s): This protocol is the equivalent for PVST, however

this protocol just can be used in conjunction with RSTP.