[c-nsp] Nexus Blocking Single Port?

[Crist J. Clark]

I am seeing some STP wierdness from a Nexus 9396 (surprise, surprise, I know).

I can't figure out why it's blocking one VLAN on a trunk to a Juniper switch,

scea-phx-core1# sh span vl 3013

VLAN3013
  Spanning tree enabled protocol rstp
  Root ID    Priority    64453
             Address     0023.04ee.be01
             This bridge is the root
             Hello Time  2  sec  Max Age 20 sec  Forward Delay 15 sec

  Bridge ID  Priority    64453  (priority 61440 sys-id-ext 3013)
             Address     0023.04ee.be01
             Hello Time  2  sec  Max Age 20 sec  Forward Delay 15 sec

Interface        Role Sts Cost      Prio.Nbr Type
---------------- ---- --- --------- -------- --------------------------------
Eth1/23          Back BLK 2         128.279  P2p 

I don't understand a lot of things going on here. It claims to be root, but
then it's blocking ports? And how can you have a backup when this is the only
port on the VLAN?
-- 
Crist J. Clark