Rapid-PVST vs. MST

[griffijo]

I have been using Rapid-PVST in my environment for several years and with good success. I've never really experienced any STP problems and RPVST has always worked as promised. I am getting ready to install equipment in some new facilities and I was considering MST instead of RPVST. I was looking for some feedback with respect to the pros and cons of MST vs. RPVST.

[Francois Tallet]

Quick pros and cons, I might be forgetting some.

MST Pros:

- IEEE standard

- scales well in terms of number of vlans handled (only one bpdu sent per physical link, efficient in term of CPU utilization).

MST cons:

- need to maintain the MST configuration identical on all switches in order to keep them into a single region.

- topology changes advertised with the granularity of the instance (not the vlan). This will be fixed when MVRP is available.

- interaction with PVST is not obvious and honestly not recommended if you can avoid it.

Rapid-PVST pros:

- Obvious migration from PVST.

- No MST configuration to handle.

- Provides the convergence speed of MST in most cases.

Rapid-PVST cons:

- one STP instance is ran per vlan (not scalable).

- proprietary. Interaction with third party bridges is not as obvious as what most engineers think (not all topologies can be achieved for vlans != 1 for example).

- Probably not as future-proof as MST (new features are rather developed with MST in mind).

Regasds,

Francois