OK, I’ve two boneheaded things I’ve done this month. This is embarrassing because my last silly mistake was burning out half the USB C ports on my MacBook Pro 2017 by buying an off-brand USB dongle.
Synology Loops Creation and RSTP and not STP
OK, this is a strange one, if you have a switch that is attached to your central one and there is an AP on it, if the link goes down, you can end up with a network loop. That is by default the APs will move to mesh mode and then if the wireline link recovers, then you have a loop that basically makes the downstream switch shut off. This causes the downstream switch to shutdown the link and you think its the switch that’s got the problem, not a loop from the AP attached to it.
RSTP stands for Rapid Spanning Tree Protocol. You need this because once a loop is detected, STP is
- To the remote switch, the link goes down
- The AP will then move to mesh mode and dutifully connect to another AP
- If the remote switch link comes up, you have a network loop
- I incorrectly changed the Settings > Networks > Spanning Tree and made sure RSTP was chosen (erroneously just clicked STP)
If you click STP, then you will see a tiny little (such a small icon, you can’t see, it but it is nearly invisible). There seems to be no way to shut this off, you have to clear the conflict.
With RSTP this gets fixed pretty much instantly (a few minutes), but STP can be a long, long, long time which is why RSTP was created
Do not just power cycle your UniFi Switch
My next mistake was just power cycling the switch. This is a mistake because the thing is software controlled and now that UniFi 24-port switch won’t adopt and connect even though it is blue and says it is happy.
The answer is that for these switches without panels, there is a RESET pin switch. If you quickly press it, then it will power on reset gracefully. That means, you should tape a paper clip onto the thing, so you can hit reset.
Finally, if you are like me and blew the installation, a long press will do a factory reset and you can start all over.
Note that for the USW 24-Port, it is a 1Gbps STP switch, so the way to hook it up is to use port aggregation. But on the reset, you should start with a single link or you will make a loop again!
Powered USB hub with 4.5V not 5V supply
OK, so this is also stupid, which is I had a USB 3.0 hub and lost the power supply and it sort of worked with one 12V supply and then another. But with a USB 2.0 hub, I found a 4.5V supply and said why don’t I plug it in. Ugh. disaster, it didn’t connect and more importantly, the voltage blew out the electronics of the downstream things I connected.
So don’t do this at home, don’t use a powered USB hub with a random supply that isn’t the same voltage 🙂
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