VLANs Range and Creating VLANs

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Different Cisco Catalyst switches support different numbers of VLANs. The number of supported VLANs is sufficient to accommodate the requirements of nearly all organizations. The Catalyst 2960 and 3560 Series switches support VLANs over 4,000. The Normal VLANs

range is numbered from 1 to 1,005 and extended-range VLANs are numbered from 1,006 to 4,094. The figure illustrates the normal range of VLANs on a Cisco switch. The Used of a normal range is used in small- and medium-sized business and enterprise networks.

VLANs Range

Normal VLANs Range 

  • The normal range VLAN ID is between 1 and 1005.
  • IDs 1002 through 1005 are reserved for Token Ring and FDDI VLANs.
  • IDs 1, 1002, 1003, 1004 and 1005 are automatically created and cannot be removed.
  • The VLAN configurations are stored in a VLAN database file, called vlan.dat. The vlan.dat file is saved in the flash memory of the switch.
  • The VTP (VLAN Trunking Protocols) helps to manage VLAN configurations between switches. The VTP can only learn and store normal range VLANs.

Extended VLANs Range

  • The extended VLANs range enables service providers to extend their infrastructure to a greater number of customers.
  • The VLAN ID is between 1006 and 4094.
  • The extended range configuration is stored by default in running configurations file instead of the vlan.dat file.
  • Support fewer VLAN features than normal range of VLANs.
  • VTP not working with extended range VLANs.

Creating VLANs

For normal range VLAN configuring, the configuration is stored vlan.dat file, which is stored in flash memory on the switch.  Flash memory does not require the copy running-config startup-config or Write command. But, other details are usually configured on a Cisco at the same time when VLANs are created; it is best to save running configuration changes to the startup configuration. The figure below illustrates the Cisco IOS command syntax used to add a VLAN to a Cisco switch and give it a name. Naming each VLAN is considered a best practice in switch configuration.

VLANs Range

The figure below illustrates the topology where VLAN 10 and 20 are configured on Switch1. We can check using the Syntax Checker show vlan brief command in user exec mode to display the contents of the vlan.dat file.

VLANs Range

We can use a series of VLAN IDs which can be entered separated by commas and we can also use a range of VLAN IDs separated by hyphens using the vlan vlan-id command. For example, use the following command to create VLANs 10, 20, 30, 40, and VLANs 50-60.

switch1(config)# vlan 10, 20, 30, 40

switch1(config)# vlan 50-60

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