Alcatel-Lucent OmniSwitch 6850-48 - Page 11

Contents
OmniSwitch AOS Release 6 Network Configuration Guide September 2009 xi
Chapter 12 Using 802.1Q 2005 Multiple Spanning Tree ....................................................12-1
In This Chapter ..............................................................................................................12-1
Spanning Tree Specifications ........................................................................................12-2
Spanning Tree Bridge Parameter Defaults ....................................................................12-2
Spanning Tree Port Parameter Defaults ........................................................................12-3
Multiple Spanning Tree Region Defaults .....................................................................12-3
MST General Overview ................................................................................................12-4
How MSTP Works .................................................................................................12-4
Comparing MSTP with STP and RSTP .................................................................12-7
What is a Multiple Spanning Tree Instance (MSTI) ..............................................12-7
What is a Multiple Spanning Tree Region .............................................................12-8
What is the Common Spanning Tree .....................................................................12-9
What is the Internal Spanning Tree (IST) Instance ................................................12-9
What is the Common and Internal Spanning Tree Instance ...................................12-9
MST Configuration Overview ....................................................................................12-10
Using Spanning Tree Configuration Commands .................................................12-10
Understanding Spanning Tree Modes ..................................................................12-11
MST Interoperability and Migration ...........................................................................12-12
Migrating from Flat Mode STP/RSTP to Flat Mode MSTP ................................12-12
Migrating from 1x1 Mode to Flat Mode MSTP ...................................................12-13
Quick Steps for Configuring an MST Region .............................................................12-14
Quick Steps for Configuring MSTIs ...........................................................................12-16
Verifying the MST Configuration ...............................................................................12-19
Chapter 13 Configuring Spanning Tree Parameters ...........................................................13-1
In This Chapter ..............................................................................................................13-2
Spanning Tree Specifications ........................................................................................13-3
Spanning Tree Bridge Parameter Defaults ...................................................................13-4
Spanning Tree Port Parameter Defaults ........................................................................13-4
Multiple Spanning Tree (MST) Region Defaults ..........................................................13-5
Ring Rapid Spanning Tree Defaults .............................................................................13-5
Spanning Tree Overview ...............................................................................................13-6
How the Spanning Tree Topology is Calculated ...................................................13-6
Bridge Protocol Data Units (BPDU) ...............................................................13-8
Topology Examples .......................................................................................13-10
Spanning Tree Operating Modes ................................................................................13-12
Using Flat Spanning Tree Mode ..........................................................................13-12
Using 1x1 Spanning Tree Mode ...........................................................................13-13
Using 1x1 Spanning Tree Mode with PVST+ .....................................................13-14
OmniSwitch PVST+ Interoperability ............................................................13-14
BPDU Processing in PVST+ Mode ...............................................................13-16
Recommendations and Requirements for PVST+ Configurations ................13-16