Lenovo ThinkSystem NE2552E, Application Manual

Page: 182 / 574

182
NE2552E Application Guide for ENOS 8.4
Manually Assigning STGs
The administrator may manually assign VLANs to specific STGs, whether or not
VASA is enabled.
1.
If no VLANs exist (other than default VLAN 1), see “Guidelines for Creating
VLANs” on page 182 for information about creating VLANs and assigning ports to
them.
2.
Assign the VLAN to an STG using one of the following methods:

From the global configuration mode:

Or from within the VLAN configuration mode:
When a VLAN is assigned to a new STG, the VLAN is automatically removed from
its prior STG.
Note:
For proper operation with switches that use Cisco PVST+, it is
recommended that you create a separate STG for each VLAN.
Guidelines for Creating VLANs
 When you create a new VLAN, if VASA is enabled (the default), that VLAN is
automatically assigned its own STG. If VASA is disabled, the VLAN
automatically belongs to STG 1, the default STG. To place the VLAN in a
different STG, see “Manually Assigning STGs” on page 182 . The VLAN is
automatically removed from its old STG before being placed into the new STG.
 Each VLANs must be contained within a single STG; a VLAN cannot span
multiple STGs. By confining VLANs within a single STG, you avoid problems
with Spanning Tree blocking ports and causing a loss of connectivity within the
VLAN. When a VLAN spans multiple switches, it is recommended that the
VLAN remain within the same STG (be assigned the same STG ID) across all the
switches.
 If ports are tagged, all aggregated ports can belong to multiple STGs.
 A port cannot be directly added to an STG. The port must first be added to a
VLAN, and that VLAN added to the desired STG.
Rules for VLAN Tagged Ports
 Tagged ports can belong to more than one STG, but untagged ports can belong
to only one STG.
 When a tagged port belongs to more than one STG, the egress BPDUs are tagged
to distinguish the BPDUs of one STG from those of another STG.
NE2552E(config)# spanning-tree stp
<STP instance or range>
vlan
<VLAN>
NE2552E(config)# vlan
<VLAN number>
NE2552E(config-vlan)# stg
<STG number>
NE2552E(config-vlan)# exit