I have a TP Link managed switch that I have enabled STP in, but it's not detecting a loop in the network, and brings the entire lan down. I plug two ends of an Ethernet cable into the switch, which creates a broadcast storm and essentially DoSes the whole network.

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I have STP enabled, along with loop protect, root protect, TC protect, and others:

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As well as storm control, but nothing seems to stop the broadcast storm once it's created:

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I don't understand why that's not stopping the loop from happening? Anyone can just plug a cable into itself and bring down the network if I don't get this STP thing to work

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    Feb 19, 2018 at 20:06

4 Answers 4


If you enable 'BPDU filtering' on the ports you're discarding the STP packets, thus breaking spanning tree. Either use STP or filter the BPDU's, don't do both.


Those are all features of spanning tree. Disable them, study them and decide if you need them.

Storm control is just throttling the specified types of traffic like multicast, broadcast.

A couple examples :

Use bpdu guard on ports that go to edge devices like a computer if you want them to shutdown when another switch is detected on that port that is using spanning tree.

BPDU filter is how you disable spanning tree on a port. Use that only when you don't want spanning tree.

Root guard needs laid out based on your topology. Disable it for now until you read up on it.

Loop protect tries to detect loops coming from switches that don't have stp. It can make ports bounce up and down if a hard loop is in place and act a little "strange".


In addition to the essential problem - filtering BPDUs - you might want to select RSTP or MSTP (whatever your switch supports) to make STP bring up the links faster.


In addition to the previous answers from Zac67 and Teun Vink, you must ensure that all switches in your network are configured with the same version of STP (STP / RSTP / MSTP /PVSTP), and set the STP priority correctly.

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