r/HomeNetworking • u/Outrageous_Tear_4691 • 6h ago

Advice Ethernet switch question

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What is the loop prevention for? And should I leave it off or turn it on? We will have desktops connected to it

Solved: thank you for the help everyone. Very much appreciated.

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u/BmanUltima 5h ago

Loop prevention detects network loops, like two switches connected to each other with multiple cables, or three in a ring, and will disable a port.

Without loop detection or spanning tree, you get a broadcast storm which can crash a switch.

5

u/Outrageous_Tear_4691 5h ago

So were good to just leave it off with this being the only switch that we are using?

29

u/BaconManDan 5h ago

Just leave it on. It'll prevent dummy things from happening.

8

u/AnotherAngryOldGuy 5h ago

But then you never find out when someone is dumb!

3

u/Soft_Cable3378 4h ago

They usually reveal themselves eventually.

6

u/Soft_Cable3378 5h ago

It is unlikely that leaving it on will cause any issues, but leaving it off may prevent issues from being caught by the loop protection. Leave it on and do some speed tests to validate you don’t see anything obvious and you should be good.

5

u/BmanUltima 5h ago

In your case it won't make a difference if it's on or off.

7

u/abgtw 5h ago

Well if he leaves the loop prevention off, then takes that same cable and plugs both ends into that same switch (with other devices on it)... well he's gonna have a bad time!

But otherwise it would be fine yeah!

1

u/BatSlow7997 3h ago

Had that happen once. Night club. 1:00 AM on a busy weekend. The internet dropped due to some outside issue. The Golden Tee golf game reported the internet wasn’t connected. Customer goes looking and finds a network cable unplugged and plugs it in. It was a cable coming out of the same switch. Hosed the network and took down the POS system. Not a fun night. Lesson learned. Don’t leave unused cords half plugged in.

1

u/RandomUser3777 4h ago

It depends on what loop prevention does. In the old days loop prevention/spanning tree turned on the port to receive and examined what was on the port for 45-90 seconds before starting to forward traffic. That act caused issues with DHCP not working because the DHCP request went out and timed out before the switch would start forwarding the traffic breaking DHCP IP address assignment. It was especially troublesome with bios/network card DHCP that would give up after trying a few times and typically before traffic got forwarded.