Multiple Spanning Tree Protocol: Difference between revisions

Revision as of 17:16, 6 December 2016

Revision as of 17:23, 6 December 2016

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}}</ref>. AMSTP is a simplified one tree instance rooted at each edge bridge in the core to forward frames.

==== Protocol Operation ====

To set up these trees, AMSTP relies in one basic tree which will be used to obtain instances (named Alternate Multiple Spanning Tree Instances – AMSTI), until one of them is built per switch for the network. The process applied to build up the main/basic tree is the same as in [[Spanning_Tree_Protocol#Rapid_Spanning_Tree_Protocol|RSTP]],. inIn summary, firstly a bridge must be elected as the Root Bridge (this is done by the emission of [[Bridge Protocol Data Unit|BPDUs]] from each switch on the network periodically, every “Hello Time”, and selecting the lowest Bridge ID). Then, every switch will compute and calculate its cost to the Root Bridge and, afterwards, the root [[Port (computer networking)|Ports]] must be elected by selecting the one which receives the best [[Bridge Protocol Data Unit|BPDU]], this is, the one that announces minimum path cost to root bridge.

==== BPDUs ====

{{Main article|Bridge Protocol Data Unit}}