Cisco 2950G 24 Software Configuration Guide - Page 349
Creating an Extended-Range VLAN
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Chapter 14 Configuring VLANs Configuring Extended-Range VLANs • STP is enabled by default on extended-range VLANs, but you can disable it by using the no spanning-tree vlan vlan-id global configuration command. When the maximum number of spanning-tree instances (64) are on the switch, spanning tree is disabled on any newly created VLANs. If the number of VLANs on the switch exceeds the maximum number of spanning tree instances, we recommend that you configure the IEEE 802.1S Multiple STP (MSTP) on your switch to map multiple VLANs to a single STP instance. For more information about MSTP, see Chapter 12, "Configuring RSTP and MSTP." Creating an Extended-Range VLAN You create an extended-range VLAN in global configuration mode by entering the vlan global configuration command with a VLAN ID from 1006 to 4094. This command accesses the config-vlan mode. The extended-range VLAN has the default Ethernet VLAN characteristics (see Table 14-2) and the MTU size is the only parameter you can change. Refer to the description of the vlan global configuration command in the command reference for defaults of all parameters. If you enter an extended-range VLAN ID when the switch is not in VTP transparent mode, an error message is generated when you exit from config-vlan mode, and the extended-range VLAN is not created. Extended-range VLANs are not saved in the VLAN database; they are saved in the switch running configuration file. You can save the extended-range VLAN configuration in the switch startup configuration file by using the copy running-config startup-config privileged EXEC command. Note Before you create an extended-range VLAN, you can verify that the VLAN ID is not used internally by entering the show vlan internal usage privileged EXEC command. If the VLAN ID is used internally and you want to free it up, go to the "Displaying VLANs" section on page 14-14 before creating the extended-range VLAN. Beginning in privileged EXEC mode, follow these steps to create an extended-range VLAN: Step 1 Step 2 Step 3 Command configure terminal vtp mode transparent vlan vlan-id Step 4 mtu mtu-size Step 5 Step 6 Step 7 end show vlan id vlan-id copy running-config startup config Purpose Enter global configuration mode. Configure the switch for VTP transparent mode, disabling VTP. Enter an extended-range VLAN ID and enter config-vlan mode. The range is 1006 to 4094. (Optional) Modify the VLAN by changing the MTU size. Note Although all commands appear in the CLI help in config-vlan mode, only the mtu mtu-size command is supported for extended-range VLANs. Return to privileged EXEC mode. Verify that the VLAN has been created. Save your entries in the switch startup configuration file. To save extended-range VLAN configurations, you need to save the VTP transparent mode configuration and the extended-range VLAN configuration in the switch startup configuration file. Otherwise, if the switch resets, it will default to VTP server mode, and the extended-range VLAN IDs will not be saved. 78-14982-01 Catalyst 2950 Desktop Switch Software Configuration Guide 14-13