Cisco Catalyst 2950 User Manual

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Catalyst 2950 and Catalyst 2955 Switch Software Configuration Guide
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Chapter 13 Configuring STP
Configuring Spanning-Tree Features
Changing the Spanning-Tree Mode
The switch supports three spanning-tree modes: PVST+, rapid PVST+, or MSTP. By default, the switch
runs the PVST+ protocol.
Beginning in privileged EXEC mode, follow these steps to change the spanning-tree mode. If you want
to enable a mode that is different from the default mode, this procedure is required.
To return to the default setting, use the no spanning-tree mode global configuration command. To return
the port to its default setting, use the no spanning-tree link-type interface configuration command.
Command Purpose
Step 1
configure terminal Enter global configuration mode.
Step 2
spanning-tree mode {pvst | mst |
rapid-pvst}
Configure a spanning-tree mode.
• Select pvst to enable PVST+ (the default setting).
• Select mst to enable MSTP (and RSTP). For more configuration
steps, see Chapter 14, “Configuring MSTP.”
• Select rapid-pvst to enable rapid PVST+.
Step 3
interface interface-id (Recommended for rapid-PVST+ mode only) Specify an interface to
configure, and enter interface configuration mode. Valid interfaces
include physical ports, VLANs, and port channels. Valid VLAN IDs are
1 to 4094. The port-channel range is 1 to 6.
Step 4
spanning-tree link-type point-to-point (Recommended for rapid-PVST+ mode only) Specify that the link type
for this port is point-to-point.
If you connect this port (local port) to a remote port through a
point-to-point link and the local port becomes a designated port, the
switch negotiates with the remote port and rapidly transitions the local
port to the forwarding state.
Step 5
end Return to privileged EXEC mode.
Step 6
clear spanning-tree detected-protocols (Recommended for rapid-PVST+ mode only) If any port on the switch
is connected to a port on a legacy IEEE 802.1D switch, restart the
protocol migration process on the entire switch.
This step is optional if the designated switch determines that this switch
is running rapid PVST+.
Step 7
show spanning-tree summary
and
show spanning-tree interface
interface-id
Verify your entries.
Step 8
copy running-config startup-config (Optional) Save your entries in the configuration file.

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