rapid-pvst

it's stp per vlan, and faster... go figure...  yes virginia, every vlan has it's own christmas tree with a load balancing ornament on top...  tuning the priority will allow some of the members of the vlan to use one of the supported links while other members of the vlan will use the one's normally blocked by stp, instead of all using the same forwarding link...

all output guaranteed from my NOHO...  (new office home office)

sw2950_02#sh spann vlan 2

VLAN0002
  Spanning tree enabled protocol rstp
  Root ID    Priority    32770
             Address     0009.b73f.ce80
             This bridge is the root
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec

  Bridge ID  Priority    32770  (priority 32768 sys-id-ext 2)
             Address     0009.b73f.ce80
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec
             Aging Time 300

Interface        Role Sts Cost      Prio.Nbr Type
---------------- ---- --- --------- -------- --------------------------------
Fa0/1            Desg BLK 19        128.1    P2p
Fa0/2            Desg BLK 19        128.2    P2p
Fa0/9            Desg BLK 19        128.9    P2p
Fa0/23          Desg FWD 19        128.23   P2p
Fa0/24          Desg BLK 19        128.24   P2p

a minor adjustment gives us this...

sw2950_02#config t
Enter configuration commands, one per line.  End with CNTL/Z.
sw2950_02(config)#int fa0/24
sw2950_02(config-if)#spann vlan 2 port-priority 0
sw2950_02(config-if)#end
sw2950_02#
2w0d: %SYS-5-CONFIG_I: Configured from console by console
sw2950_02#sh spann vl 2

VLAN0002
  Spanning tree enabled protocol rstp
  Root ID    Priority    4098
             Address     0009.b73f.ce80
             This bridge is the root
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec

  Bridge ID  Priority    4098   (priority 4096 sys-id-ext 2)
             Address     0009.b73f.ce80
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec
             Aging Time 300

Interface        Role Sts Cost      Prio.Nbr Type
---------------- ---- --- --------- -------- --------------------------------
Fa0/1            Desg FWD 19        128.1    P2p
Fa0/2            Desg FWD 19        128.2    P2p
Fa0/9            Desg FWD 19        128.9    P2p
Fa0/23          Desg FWD 19        128.23   P2p
Fa0/24          Desg FWD 19          0.24   P2p

sw2950_02#

aaaaaahhhhhhhhhhhhh...