CHAPTE R
22-1
Cisco IE 2000 Switch Software Configuration Guide
OL-25866-01
22
Configuring Optional Spanning-Tree Features
Finding Feature Information
Your software release may not support all the features documented in this chapter. For the latest feature
information and caveats, see the release notes for your platform and software release.
Use Cisco Feature Navigator to find information about platform support an d Cisco software image
support. To access Cisco Feature Navigator, go to http://www.cisco.com/go/cfn. An account on
Cisco.com is not required.
Prerequisites for the Optional Spanning-Tree Features
You can configure all of these features when your switch is running the per-VLAN spanning-tree plus
(PVST+). You can configure only the noted features when your switch is running the Multipl e Spanning
Tree Protocol (MSTP) or the rapid per-VLAN spanning-tree plus (rapid-PVST+) protocol.
Restrictions for the Optional Spanning-Tree Features
You can configure the UplinkFast or the BackboneFast feature for rapid PVST+ or for the MSTP, but the
feature remains disabled (inactive) until you change the spanning-tree mode to PVST+.
Information About Configuring the Optional Spanning-Tree
Features
PortFast
PortFast immediately brings an interface configured as an access or trunk port to the forwarding state
from a blocking state, bypassing the listening and learning states. You can use PortFast on interfaces
connected to a single workstation or server, as shown in Figure 22-1, to allow those devices to
immediately connect to the network, rather than waiting for the spanning tree to converge.