PortFast only needs to be enabled on ports that connect to workstations or PCs. Repeat these
commands for every port connected to workstations or PCs. Do not enable PortFast on ports
that connect to other switches.

switch(config)#interface tengigabitethernet 0/10

switch(conf-if-te-0/10)#spanning-tree portfast

switch(conf-if-te-0/10)#exit

switch(config)#interface tengigabitethernet 0/11

switch(conf-if-te-0/11)#spanning-tree portfast

switch(conf-if-te-0/11)#exit

Repeat these commands for every port connected to workstations or PCs.

13. Set the following ports to forwarding mode:

•

All ports of the root switch

•

The root port

•

The designated port

For details, see

“Specifying the port priority”

on page 61.

14. Enable the guard root feature with the spanning-tree guard root command. The guard root

feature provides a way to enforce the root bridge placement in the network. For detailed
information, refer to

“Enabling the guard root”

on page 59. Note that this step is optional.

All other switch ports connect to other switches and bridges are automatically placed in
blocking mode.

This does not apply to ports connected to workstations or PCs; these ports remain in the
forwarding state.

15. Enter the copy command to save the running-config file to the startup-config file.

switch(conf-if-te-0/1)#exit

switch(config)#end

switch#copy running-config startup-config

MSTP overview

The IEEE 802.1s Multiple STP (MSTP) helps create multiple loop-free active topologies on a single
physical topology. MSTP enables multiple VLANs to be mapped to the same spanning tree instance
(forwarding path), which reduces the number of spanning tree instances needed to support a large
number of VLANs. Each MSTP instance has a spanning tree topology independent of other