***WORK IN PROGRESS*** SPANNING TREE EXAMPLE PICTURE Original Spanning Tree - 802. 1d PASSIVE (convergence 50 sec + ) *Blocking - 0-26 sec *Listening - 15 sec *Learning - 15 sec Rapid Spanning Tree - 802. 1w RSTP ACTIVE (convergence 2 sec ) Per Vlan Rapid Spanning Tree PVSTP ACTIVE 1 instance per vlan (can be different topology per vlan) Multiple Spanning Tree MSTP ACTIVE cut down on spanning tree instances Region Matching Name Matching Revision No Matching Mapping e.g. instance 0 - catch all (internal spanning tree) instance 1 - vlan 11 to 20 instance 2 - vlan 21 to 30 *Rules 1. Root bridge election 2. Best path to the root 2a. lowest cost 2b. lowest ID 3c. lowest port number (advertising switch) *no more than 7 in the chain* BPDU - bridge protocol data unit every 2 seconds Root and Loop detection Multicast Address 01:80:c2:00:00:00 Bridge MAC + Bridge Priority = Bridge ID Find best path to the root using cost DP designated port (one per segment) RP root port *AP alternate port (backup to RP) BP blocked port Bridge Assurance - disables ports if BPDU is NOT seen LoopGuard - RP/AP can't become DP RootGuard - apply on switch port to another LAN BPDU Guard - disables ports if BPDU is seen PortFast - disables spanning tree BPDU filter - MAC flap ???? |
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