user manual

Chapter 1 Configuring Interfaces and Circuits
Configuring Interfaces
1-16
Cisco Content Services Switch Routing and Bridging Configuration Guide
OL-4580-01
Configuring Spanning-Tree Bridge State
By default, an Ethernet interface is set to the enabled bridge state Use the bridge
state command to set the spanning-tree bridge state for an Ethernet interface or
for a trunked Ethernet interface. .
For example, to enable the bridge state for e7 on the CSS 11501, enter:
(config-if[e7])# bridge state enable
For example, to enable the bridge state for the I/O module in slot 1, Ethernet
port 1, in VLAN3, enter:
(config-if-vlan[1/1-3])# bridge state enable
To disable the bridge state, enter:
(config-if-vlan[1/1-3])# bridge state disable
Configuring Port Fast on an Interface
The Port Fast feature immediately brings a CSS Ethernet interface (port) to the
Spanning Tree Protocol (STP) forwarding state from a blocking state, bypassing
the listening and learning states. You can specify Port Fast for ports connected to
a single workstation or server to allow those devices to immediately connect to
the network, rather than waiting for the STP to converge.
Ports connected to a single workstation or server should not receive bridge
protocol data units (BPDUs).
Caution The purpose of Port Fast is to minimize the time ports must wait for STP to
converge. This means that the Port Fast function is effective only when used on
ports connected to end stations in the network. If you enable Port Fast on a port
connecting to another switch, you risk creating a spanning-tree loop. Consider
using the BDPU guard feature to avoid creating a spanning-tree loop.
This section includes the following topics:
• Enabling Port Fast
• Enabling BPDU Guard
• Showing Port Fast Information