[j-nsp] Help with MSTP in EX8208

[Chuck Anderson]

On Wed, Apr 02, 2014 at 03:36:51PM +0200, Octavio Alfageme wrote:
> I would like to have ae2.0 blocked in instance 1 and ge-20/0/1.0 blocked in
> instance 2. That's why I modify the cost of ae2.0 interface within instance
> 1 in both switches:
>
> Could you, please, help me to discover what I'm doing wrong?

Change the msti bridge priority, but make sure you use 4k boundaries.

I use 0 for the root bridge, and 4k for the other:

msti 1 {
    bridge-priority 0;
    vlan ....
}
msti 2 {
    bridge-priority 4k;
    vlan ....
}

That way if another device is attached without proper configuration,
the default value of 32k will never override my configured root
bridges.

For switches that I configure to be attached to the core switches, I
use bridge priorities of 16k, 20k and 24k, going higher for each
additional hop away from the core switches, but still lower than the
default 32k.