Cisco Catalyst 2950 User Manual

16-14
Catalyst 2950 and Catalyst 2955 Switch Software Configuration Guide
78-11380-12
Chapter 16 Configuring VLANs
Displaying VLANs
Displaying VLANs
Use the show vlan privileged EXEC command to display a list of all VLANs on the switch, including
extended-range VLANs. The display includes VLAN status, ports, and configuration information. To
view normal-range VLANs in the VLAN database (1 to 1005) use the show VLAN configuration
command (accessed by entering the vlan database privileged EXEC command). For a list of the VLAN
IDs on the switch, use the show running-config vlan privileged EXEC command, optionally entering a
VLAN ID range.
Table 16-3 lists the commands for monitoring VLANs.
For more details about the show command options and explanations of output fields, see the command
reference for this release.
Configuring VLAN Trunks
These sections describe how VLAN trunks function on the switch:
• Trunking Overview, page 16-14
• IEEE 802.1Q Configuration Considerations, page 16-16
• Default Layer 2 Ethernet Interface VLAN Configuration, page 16-17
Trunking Overview
A trunk is a point-to-point link between one or more Ethernet switch interfaces and another networking device
such as a router or a switch. Fast Ethernet and Gigabit Ethernet trunks carry the traffic of multiple VLANs
over a single link, and you can extend the VLANs across an entire network.
The switch supports IEEE 802.1Q, the industry-standard trunking encapsulation.
Figure 16-2 shows a network of switches that are connected by IEEE 802.1Q trunks.
Table 16-3 VLAN Monitoring Commands
Command Command Mode Purpose
show VLAN configuration Display status of VLANs in the VLAN database.
show current [vlan-id] VLAN configuration Display status of all or the specified VLAN in the
VLAN database.
show interfaces [vlan
vlan-id]
Privileged EXEC Display characteristics for all interfaces or for
the specified VLAN configured on the switch.
show running-config vlan Privileged EXEC Display all or a range of VLANs on the switch.
show vlan [id vlan-id] Privileged EXEC Display parameters for all VLANs or the
specified VLAN on the switch.

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