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Cisco Catalyst Blade Switch 3130 for Dell Software Configuration Guide
OL-13270-01
Chapter12 Configuring VLANs
Configuring Normal-Range VLANs
Token Ring VLANs
Although the switch does not support Token Ring connections, a remote device such as a Catalyst 5000
series switch with Token Ring connections could be managed from one of the supporte d switche s.
Switches running VTP Version 2 advertise information about these Token Ring VLANs:
•Token Ring TrBRF VLANs
•Token Ring TrCRF VLANs
For more information on configuring Token Ring VLANs, see the Catalyst 5000 Series Software
Configuration Guide.
Normal-Range VLAN Configuration Guidelines
Follow these guidelines when creating and modifying normal-range VLANs in your network:
•The switch supports 1005 VLANs in VTP client, server, and transparent modes.
•Normal-range VLANs are identified with a number between 1 an d 1001 . VL AN nu mber s 10 02
through 1005 are reserved for Token Ring and FDDI VLANs.
•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 sav ed i n th e swi tch run ning configuration file.
•The switch also supports VLAN IDs 1006 through 4094 in VTP transparent mode (VTP disabled) .
These are extended-range VLANs and configuration options are limited. Extended-ra nge VLA Ns
are not saved in the VLAN database. See the “Configuring Extended-Range VLANs” section on
page 12-12.
•Before you can create a VLAN, the switch must be in VTP server mode or VT P tra nsp aren t mode.
If the switch is a VTP server, you must define a VTP domain or VTP will not function.
•The switch does not support Token Ring or FDDI media. The switch does not forward FDD I,
FDDI-Net, TrCRF, or TrBRF traffic, but it does propagate the VLAN configuration throughVTP.
•The switch supports 128 spanning-tree instances. If a switch has more active VLANs than s upported
spanning-tree instances, spanning tree can be enabled on 128 V L ANs a nd is di sabl ed 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 (w hic h
is to allow all VLANs), the new VLAN is carried on all trunk ports. Depending o n the topo l ogy of
the network, this could create a loop in the new VLAN that would not be broken, particularl y 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 su ppo rt ed sp an ni ng-t ree inst an ces,
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. For more information about MSTP, see
Chapter 18, “Configuring MSTP.”
•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 stack master.