Contents
vi OmniSwitch AOS Release 7 Network Configuration Guide June 2013
Spanning Tree Overview .................................................................................................6-6
How the Spanning Tree Topology is Calculated .....................................................6-6
MST General Overview ................................................................................................6-12
How MSTP Works .................................................................................................6-12
Comparing MSTP with STP and RSTP .................................................................6-15
What is a Multiple Spanning Tree Instance (MSTI) ..............................................6-15
What is a Multiple Spanning Tree Region .............................................................6-16
What is the Common Spanning Tree .....................................................................6-17
What is the Internal Spanning Tree (IST) Instance ................................................6-17
What is the Common and Internal Spanning Tree Instance ...................................6-17
MST Configuration Overview ...............................................................................6-17
MST Interoperability and Migration ......................................................................6-18
Spanning Tree Operating Modes ..................................................................................6-20
Using Flat Spanning Tree Mode ............................................................................6-20
Using Per-VLAN Spanning Tree Mode .................................................................6-21
Using Per-VLAN Spanning Tree Mode with PVST+ ............................................6-22
OmniSwitch PVST+ Interoperability .....................................................................6-23
Using Spanning Tree Configuration Commands ..........................................................6-25
Configuring STP Bridge Parameters .............................................................................6-26
Selecting the Spantree Protocol ..............................................................................6-27
Configuring the Bridge Priority .............................................................................6-27
Configuring the Bridge Hello Time .......................................................................6-28
Configuring the Bridge Max-Age Time .................................................................6-29
Configuring the Forward Delay Time for the Switch ............................................6-29
Enabling/Disabling the VLAN BPDU Switching Status .......................................6-30
Configuring the Path Cost Mode ............................................................................6-31
Using Automatic VLAN Containment ...................................................................6-31
Configuring STP Port Parameters .................................................................................6-33
Enabling/Disabling Spanning Tree on a Port .........................................................6-34
Configuring Port Priority .......................................................................................6-36
Configuring Port Path Cost ....................................................................................6-37
Configuring Port Mode ..........................................................................................6-40
Configuring Port Connection Type ........................................................................6-41
Configuring the Edge Port Status ...........................................................................6-42
Restricting Port Roles (Root Guard) ......................................................................6-43
Restricting TCN Propagation .................................................................................6-43
Limiting BPDU Transmission ................................................................................6-43
Sample Spanning Tree Configuration ...........................................................................6-44
Example Network Overview ..................................................................................6-44
Example Network Configuration Steps ..................................................................6-45
Sample MST Region Configuration ..............................................................................6-47
Sample MSTI Configuration .........................................................................................6-49
Verifying the Spanning Tree Configuration .................................................................6-52