[c-nsp] MST to Rapid PVST+ interaction.

[Kevin Barrass]

Hi

On a test network we have an MST core network that we are testing how to
connect clients to resiliently.
Most of our clients use Rapid PVST+. If we simulate the clients network
with a single switch running Rapid PVST+ and connect two access ports
from this to the MST core network one interface is set to BLK-ALT as
expected and the 2 ports on the MST core and client network switch runs
in rapid spanning compatibility mode giving fast convergence using the
MST IST.

The problem is when we configure the 2 interface on both the MST core
network and client network switch to be dot1q trunks even with only one
vlan allowed all works the same other than the ports on the MST core
show as operating in Standard spanning tree mode, loosing the fast
convergence of MST or Rapid PVST+.

Has anyone come across this as there is very little documentation out
there for this kind of setup. Ive even tried the Cisco.com Forums.
The hardware is MST core made of Cisco 4507s running 12.1(19)EW1 and a
Cisco 2950s.
If this is too vague please let me know and I can provide more info.

Kev Barrass