Dell S3048-ON User Manual

Multiple Spanning Tree Protocol (MSTP)
Multiple spanning tree protocol (MSTP) — specied in IEEE 802.1Q-2003 — is a rapid spanning tree protocol (RSTP)-based spanning tree
variation that improves per-VLAN spanning tree plus (PVST+). MSTP allows multiple spanning tree instances and allows you to map many
VLANs to one spanning tree instance to reduce the total number of required instances.
Protocol Overview
MSTP — specied in IEEE 802.1Q-2003 — is a rapid spanning tree protocol (RSTP)-based spanning tree variation that improves on per-
VLAN spanning tree plus (PVST+). MSTP allows multiple spanning tree instances and allows you to map many VLANs to one spanning tree
instance to reduce the total number of required instances.
In contrast, PVST+ allows a spanning tree instance for each VLAN. This 1:1 approach is not suitable if you have many VLANs, because each
spanning tree instance costs bandwidth and processing resources.
In the following illustration, three VLANs are mapped to two multiple spanning tree instances (MSTI). VLAN 100 trac takes a dierent
path than VLAN 200 and 300 trac. The behavior demonstrates how you can use MSTP to achieve load balancing.
Figure 81. MSTP with Three VLANs Mapped to TWO Spanning Tree Instances
Topics:
• Spanning Tree Variations
• Congure Multiple Spanning Tree Protocol
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Multiple Spanning Tree Protocol (MSTP) 497

Dell S3048-ON Specifications

General

Brand	Dell
Model	S3048-ON
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Language	English