Dell Z9000 Configuration Manual

Also see for Z9000: Installing Configuration guide Quick start guide Manual

Contents

Dell Z9000 Configuration Manual Manual pdf 513 page image

28Multiple Spanning Tree Protocol (MSTP)Multiple spanning tree protocol (MSTP) is supported on Dell Networking OS.Protocol OverviewMSTP — specified in IEEE 802.1Q-2003 — is a rapid spanning tree protocol (RSTP)-based spanning treevariation that improves on per-VLAN spanning tree plus (PVST+). MSTP allows multiple spanning treeinstances and allows you to map many VLANs to one spanning tree instance to reduce the total numberof required instances.In contrast, PVST+ allows a spanning tree instance for each VLAN. This 1:1 approach is not suitable if youhave 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 traffic takes a different path than VLAN 200 and 300 traffic. The behavior demonstrates howyou can use MSTP to achieve load balancing.Figure 78. MSTP with Three VLANs Mapped to TWO Spanning Tree InstancesMultiple Spanning Tree Protocol (MSTP) 513