mixing rstp and mstp

[Miguel S. Sanchez]

Ive got a few 2500 series switches as well as a few 2800 switches. Ive enabled spanning tree on each of them, but the 2500 series use RSTP and the 2800 use MSTP. From what Ive read they should be backwards compatible, but I tried plugging a 2524 into a 2810 and it did not block the port I was expecting it to block.

Are these truly compatible? Im using all default settings. Should I set my 2800s to use RSTP?

[DaGuru]

MSTP should treat RSTP as expected in instance 0. What did you experience that you didn't expect?

Remember, by default, root election will be based on switch MAC address if all other STP values are the same.

[AtticaNet]

I have some H3C 5500 switches that use MST and I have 3 instances. MST Instance 1 has VLAN 11, MST Instance 2 has VLAN 12 and the MST Instance 0 has VLAN 1.
The switches running RSTP run the VLAN 12. Does this mean I will have to modify my VLAN assignment on the MST instances? Like move the VLAN 12 from instance 2 to the instance 0?