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Catalyst 2950 Desktop Switch Software Configuration Guide
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Chapter 14 Configuring VLA Ns Configuring Extended-Range VLANs
•STP is enable d by default on extended -range V LANs, but you can di sable it by using the no
spanning-tre e vlan vlan-id global co nfigurat ion c omman d. Wh en the m axi mum n umb er o f
spanning-tree instances (64) are on the switch, spanning tree is disabled on any newly created
VLANs . If t he n umb er o f VL ANs on the sw itc h exc eeds the m axim um nu mber of sp an ning tre e
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

Yo u crea t e an exten de d-r ange V LAN i n g lob al configur atio n m ode by ente ring t he vlan global
configurati on comm and with a VLA N ID from 1006 to 4094. Th is comma nd accesse s the config-vl an
mode. The extended-ra nge VLA N has the default Ethernet VLAN char acte ristics (se e Table 14-2) a nd
the MTU si ze is the on ly paramet er you can change. Refer to the de script ion of the vlan glob al
configurat ion c omm and in the co mma nd r efer en ce f or defau lts of a ll para met ers . If yo u e nte r an
extended-range VLAN ID when the switch is not in VTP transparent mode, an error message is
genera ted whe n you exit from config-v lan mode , and th e extended -rang e VLAN is not creat ed.
Extended-range VLANs are not saved in the VLAN database; they are saved in the switch running
configurati on file. You can save the extende d- range VL A N co nfigurat ion in t he swi tch star tup
configurat ion file by using t he copy running-config startup-config privileged EXEC command.
Note Be fore you create an extended-range VLAN, you can verify that the VLAN ID is not used intern ally by
ent erin g th e 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:
Command Purpose
Step 1 configure terminal Enter global co nfiguration mo de.
Step 2 vtp mode transparent Configure the switch for VTP transparent mode, disabling VTP.
Step 3 vlan vlan-id Enter a n ext ende d- range VL A N ID and e nt er co nfig-vla n mo de. T he
range is 10 06 to 4094.
Step 4 mtu mtu-size (Optional) Modify the VLAN by changing the MTU size.
Note A lthough a ll comm a nds ap pe ar in the CL I he lp in config- vlan
mode, onl y the mtu mtu-size command is supported for
extended-range VLANs.
Step 5 end Return to privileged EXEC mode.
Step 6 show vlan id vlan-id Veri fy th at the V LAN has been creat ed.
Step 7 copy running-config startup config Save your entri es in the switc h startup co nfiguration file. To save
extended -rang e VLA N c onfigura tio ns, yo u n eed t o s ave the VTP
transparent mode configuration and the extended-range VLAN
configuration in the switch startup configuration file. Otherwise, if the
switch resets, it wi ll def ault to VTP serv er mode, and the e xten ded-rang e
VLAN IDs will not be saved.