Cisco Catalyst 2950 Command Reference

2-473
Catalyst 2950 and Catalyst 2955 Switch Command Reference
0L-10102-01
Chapter 2 Catalyst 2950 and 2955 Cisco IOS Commands
spanning-tree portfast (global configuration)
spanning-tree portfast (global configuration)
Use the spanning-tree portfast global configuration command to globally enable bridge protocol data
unit (BPDU) filtering on Port Fast-enabled ports, the BPDU guard feature on Port Fast-enabled ports, or
the Port Fast feature on all nontrunking ports. The BPDU filtering feature prevents the switch port from
sending or receiving BPDUs. The BPDU guard feature puts Port Fast-enabled ports that receive BPDUs
in an error-disabled state. Use the no form of this command to return to the default setting.
spanning-tree portfast {bpdufilter default | bpduguard default | default}
no spanning-tree portfast {bpdufilter default | bpduguard default | default}
Syntax Description
Defaults The BPDU filtering, the BPDU guard, and the Port Fast features are disabled on all ports unless they are
individually configured.
Command Modes Global configuration
Command History
Usage Guidelines You can enable these features when the switch is operating in the per-VLAN spanning-tree plus
(PVST+), rapid-PVST+, or the multiple spanning-tree (MST) mode.
Use the spanning-tree portfast bpdufilter default global configuration command to globally enable
BPDU filtering on ports that are Port Fast-enabled (the ports are in a Port Fast-operational state). The
ports still send a few BPDUs at link-up before the switch begins to filter outbound BPDUs. You should
globally enable BPDU filtering on a switch so that hosts connected to switch ports do not receive
BPDUs. If a BPDU is received on a Port Fast-enabled port, the port loses its Port Fast-operational status
and BPDU filtering is disabled.
You can override the spanning-tree portfast bpdufilter default global configuration command by
using the spanning-tree bdpufilter interface configuration command.
bpdufilter default Globally enable BPDU filtering on Port Fast-enabled ports and prevent the
switch port connected to end stations from sending or receiving BPDUs.
bpduguard default Globally enable the BPDU guard feature on Port Fast-enabled ports and place
the ports that receive BPDUs in an error-disabled state.
default Globally enable the Port Fast feature on all nontrunking ports. When the Port
Fast feature is enabled, the port changes directly from a blocking state to a
forwarding state without making the intermediate spanning-tree state
changes.
Release Modification
12.1(6)EA2 This command was introduced.
12.1(9)EA1 The bpdufilter default and default keywords were added.

Cisco Catalyst 2950 Specifications

General

Forwarding Bandwidth	8.8 Gbps
Switching Capacity	13.6 Gbps
Forwarding Rate	6.6 Mpps
Weight	3.6 kg
RAM	16 MB
Flash Memory	8 MB
Operating Humidity	10% to 85% non-condensing
Uplink Ports	2 x 10/100/1000Base-T
Dimensions	4.4 cm x 44.5 cm x 24.2 cm
Remote Management Protocol	SNMP, Telnet, HTTP
Features	Quality of Service (QoS), VLAN support
Compliant Standards	IEEE 802.3, IEEE 802.3u, IEEE 802.1D, IEEE 802.1Q, IEEE 802.1p
Status Indicators	system
Operating Temperature	0 to 45°C
Ports	24 x 10/100 Ethernet ports
MAC Address Table Size	8, 192 entries
Power Supply	Internal 100-240V AC, 50-60Hz