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Tag: STP

CCIE: Root Guard, BPDU Guard, BPDU Filter, and Loop Guard

CCIE: Root Guard, BPDU Guard, BPDU Filter, and Loop Guard

The BPDU guard feature can be globally enabled on the switch or can be enabled per port, but the feature operates with some differences. At the global level, you enable BPDU guard on Port Fast-enabled ports by using the spanning-tree portfast bpduguard default global configuration command. Spanning tree shuts down ports that are in a Port Fast-operational state if any BPDU is received on them. In a valid configuration, Port Fast-enabled ports do not receive BPDUs. Receiving a BPDU on a Port…

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CCIE: STP (802.1d)

CCIE: STP (802.1d)

So, first a little history on Spanning tree protocol (STP). Based on an algorithm created by Radia Pearlman in 1985. http://en.wikipedia.org/wiki/Radia_Perlman Became a standard IEEE protocol in 1990. Still widely deployed. Flavors of spanning tree. 802.1d (ieee), 802.1w (rapid), and 802.1s (mst). Evolution of STP, Cisco vPC (2-way non blocking, still requires STP) and Fabric Path (eliminates STP completely). TRILL is a standardized version of Fabric Path. Both TRILL and Fabric Path utilize a link state protocol (IS-IS) as their loop prevention method. Specific Cisco enhancement to 802.1d (prior to 802.1w):…

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