If you are running MSTP, you can add members to a spanning tree instance. An
is a VLAN. You add members to an instance by associating one or more VLANs with
the instance. The interfaces or trunks associated with each VLAN automatically become part of the
spanning tree corresponding to that instance.
For two or more bridges to operate in the same spanning tree, all of those bridges must be in the same region, and therefore must have the same instance numbers, instance members, and VLAN tags.
For example, if a bridge has instance 1, with two VLAN members whose tags are 1000 and 2000,
then any other bridges that you want to operate in that spanning tree must also have instance 1
with two VLAN members whose tags are 1000 and 2000.
A particular VLAN cannot be associated with more than one spanning tree instance. For example, if you have two instances named 0 and 1, you can only associate VLAN external with one of those instances, not both. Therefore, before creating an instance, verify that each VLAN you intend to associate with the instance is not a member of another instance.
If no VLANs appear in the
list when creating an
instance, it is likely that all VLANs on the BIG-IP®
system are members
of other instances. You can verify this by viewing the members of other instances.