From the course: Cisco Certified Network Associate (CCNA) v1.1 (200-301) Cert Prep

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STP convergence times

STP convergence times

From the course: Cisco Certified Network Associate (CCNA) v1.1 (200-301) Cert Prep

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STP convergence times

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(gentle music) - [Instructor] We know that the spanning tree protocol allows us to have physically redundant links while logically having a loop free topology, and that's what we have here. We see that on switch SW3 interface gig 0/2 is currently blocking. We do not have user traffic flowing over that bottom link and switch three and switch two, they're both pointing up to switch one and switch three is getting to switch one via interface gig 0/1 because switch one, that is our root bridge. However, let's imagine that there was a failure on that link between switch one and switch three. After all, that's what Spanning Tree is built for, to help us recover from something like that. The question we're going to answer in this video is how long does it take to recover? Do we immediately start forwarding traffic out of gigabit 0/2? Actually, no. We're going to remain in that blocking state for 20 seconds. Switch SW3 is waiting for bridge protocol data units, BPDUs, to be received from…

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