Normal-Range VLAN Configuration Guidelines
Normal-range VLANs are VLANs with IDs from 1 to 1005. VTP 1 and 2 only support normal-range VLANs.
Follow these guidelines when creating and modifying normal-range VLANs in your network:
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Normal-range VLANs are identified with a number between 1 and 1001. VLAN numbers 1002 through
1005 are reserved for Token Ring and FDDI VLANs.
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VLAN configuration for VLANs 1 to 1005 are always saved in the VLAN database. If the VTP mode
is transparent, VTP and VLAN configuration are also saved in the switch running configuration file.
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If the switch is in VTP server or VTP transparent mode, you can add, modify or remove configurations
for VLANs 2 to 1001 in the VLAN database. (VLAN IDs 1 and 1002 to 1005 are automatically created
and cannot be removed.)
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With VTP versions 1 and 2, the switch supports VLAN IDs 1006 through 4094 only in VTP transparent
mode (VTP disabled). These are extended-range VLANs and configuration options are limited.
Extended-range VLANs created in VTP transparent mode are not saved in the VLAN database and are
not propagated. VTP version 3 supports extended range VLAN (VLANs 1006 to 4094) database
propagation in VTP server and transparent mode. If extended VLANs are configured, you cannot convert
from VTP version 3 to version 1 or 2.
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Before you can create a VLAN, the switch must be in VTP server mode or VTP transparent mode. If
the switch is a VTP server, you must define a VTP domain or VTP will not function.
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The switch does not support Token Ring or FDDI media. The switch does not forward FDDI, FDDI-Net,
TrCRF, or TrBRF traffic, but it does propagate the VLAN configuration through VTP.
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The switch supports 128 spanning tree instances. If a switch has more active VLANs than supported
spanning-tree instances, spanning tree can be enabled on 128 VLANs and is disabled on the remaining
VLANs. If you have already used all available spanning-tree instances on a switch, adding another
VLAN anywhere in the VTP domain creates a VLAN on that switch that is not running spanning-tree.
If you have the default allowed list on the trunk ports of that switch (which is to allow all VLANs), the
new VLAN is carried on all trunk ports. Depending on the topology of the network, this could create a
loop in the new VLAN that would not be broken, particularly if there are several adjacent switches that
all have run out of spanning-tree instances. You can prevent this possibility by setting allowed lists on
the trunk ports of switches that have used up their allocation of spanning-tree instances.
If the number of VLANs on the switch exceeds the number of supported 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 spanning-tree instance.
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When a switch in a stack learns a new VLAN or deletes or modifies an existing VLAN (either through
VTP over network ports or through the CLI), the VLAN information is communicated to all stack
members.
•
When a switch joins a stack or when stacks merge, VTP information (the vlan.dat file) on the new
switches will be consistent with the active switch.
Related Topics
Creating or Modifying an Ethernet VLAN, on page 11
Deleting a VLAN, on page 14
Assigning Static-Access Ports to a VLAN, on page 17
Consolidated Platform Configuration Guide, Cisco IOS XE Release 3SE (Catalyst 3850 Switches)
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Configuring VLANs
Normal-Range VLAN Configuration Guidelines
