spann-fastie's...

turn it up...

portfast - use the portfast command on access ports to bypass spanning convergence for hosts (pc's, printers, etc.); keep the tree for the trunks...


sw2950_01(config)#int fa0/12
sw2950_01(config-if)#spann portfast
%Warning: portfast should only be enabled on ports connected to a single
 host. Connecting hubs, concentrators, switches, bridges, etc... to this
 interface  when portfast is enabled, can cause temporary bridging loops.
 Use with CAUTION

%Portfast has been configured on FastEthernet0/12 but will only
 have effect when the interface is in a non-trunking mode.
sw2950_01(config-if)#

uplinkfast - when an uplink to the root fails,  another link is brought up immediately... do not use uplinkfast on the root switch... use it on every other switch in the diameter.  it is enabled globally


sw2950_02#sh spann vlan 20
VLAN0020
  Spanning tree enabled protocol ieee
  Root ID    Priority    32788
             Address     0009.b73f.ce80
             This bridge is the root
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec

  Bridge ID  Priority    32788  (priority 32768 sys-id-ext 20)
             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

sw2950_02(config)#spann uplinkfast

sw2950_02(config)#do sh spann vlan 20

expect topology changes...

VLAN0020

  Spanning tree enabled protocol ieee

  Root ID    Priority    32788

             Address     0009.b752.d780

             Cost        3019

             Port        1 (FastEthernet0/1)

             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec

  Bridge ID  Priority    49172  (priority 49152 sys-id-ext 20)

             Address     0009.b73f.ce80

             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec

             Aging Time 15

  Uplinkfast enabled

Interface        Role Sts Cost      Prio.Nbr Type

---------------- ---- --- --------- -------- --------------------------------

Fa0/1            Root FWD 3019      128.1    P2p

Fa0/2            Altn BLK 3019      128.2    P2p

backbonefast - allows a switch to save about twenty seconds recovering from an indirect link failure... used on all switches in the diameter and is enabled globally...

sw2950_02(config)#spann backbone