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Madumi
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cAP ac / v6.40.4 - frequent disconnects?

Tue Oct 23, 2018 5:53 pm

I have a cAP ac running on the POE of a ubiquiti ER-X, supply cable is Cat5e 30 feet...

Device is disconnecting from the network multiple times every hour (ER-X logs)

Any suggestions how to troubleshoot this?
 
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Madumi
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Re: cAP ac / v6.40.4 - frequent disconnects?

Tue Oct 23, 2018 8:27 pm

To help eliminate potential problems, I upgraded to the latest firmware (v6.43.4).

Over the last two hours since then, the cAP ac has continued to disconnect & reconnect 10 times. It doesn't go down for long, usually 4-9seconds, but I would love to solve this issue.
 
anav
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Re: cAP ac / v6.40.4 - frequent disconnects?

Tue Oct 23, 2018 10:09 pm

I have two cap AC, but not sure which firmware I have but will check later.
How did you figure out you were having timeouts every xx seconds?
In other words what test can i setup to discover if I am or am not having such issues and thus help you isolate the cause of your issues.
Mine are poe supplied by the provided mikrotik poe adapter plugged into the ac outlet on one hand and a switch on the other.
I'd rather manage rats than software. Follow my advice at your own risk! (Sob & mkx forced me to write that!)
 
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Madumi
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Re: cAP ac / v6.40.4 - frequent disconnects?

Wed Oct 24, 2018 8:32 pm

@anav, all I'm doing is checking the syslogs on the device to which the cAP ac is connected. It lists the interface (eth4) & times of disconnection & connection.

Interestingly, there's no one in the house at the moment... and the logs are silent (it's constant for now). Last log was a "connected"

people are going to be back at the house on Monday, so I'll see what happens then. I'm assuming the frequent connect/disconnect logs will start up again.

I'd be super interested if there's a good way to troubleshoot what's up.
I'm new to RouterOS & when I check WebFig->Log, I only see the last handfull of entries, starting with "router was rebooted without proper shutdown." Is there an easy way to retain entries longer than a single boot?
 
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Madumi
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Re: cAP ac / v6.40.4 - frequent disconnects?

Mon Oct 29, 2018 4:46 pm

Any suggestions how to trouble shoot this one?

Monday has rolled around & people are back in the house... After four days of no eth port disconnects on the cAP ac, it's again showing disconnects every 10-15 minutes (now that people are using it).

any hints? thx!
 
mkx
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Re: cAP ac / v6.40.4 - frequent disconnects?

Mon Oct 29, 2018 11:05 pm

I'm new to RouterOS & when I check WebFig->Log, I only see the last handfull of entries, starting with "router was rebooted without proper shutdown." Is there an easy way to retain entries longer than a single boot?
You can either configure sending log messages to some other machine running syslog or you can configure writing logs to disk. In theory you can use the built-in storage for that but that's highly discouraged (many devices lack decently sized storage plus writing logs to NAND would considerably shorten its life time). Or you can plug some USB stick (if your RB has USB jack) and configure writing logs to that device. Those logs survive reboots. However, initial surge of logs (just after boot) will not get written to disk because of delay in disk initialization. I'm kind of disapointed that those logs are not flushed after disk for logging gets available (I might write a question to support@mikrotik.com some day).

To return to your original problem: when WiFi traffic increases, also power consumed by AP device increases. cAP ac needs at least 17V power input, if voltage drops below that, it might restart. Higher power consumption means higher current and higher current means higher voltage drop on wires. While standards require quite low DC resistance of UTP cables and current of 0.5A through 30 feet of UTP cable should not cause too high voltage drop, use of sub-standard cables or non-perfect plugs and outlets or even oxidation could increase resistance of the PoE feed between ER-X and cAP ac to the point where voltage on PoEin porte of cAP ac would drop too low. I'd investigate this scenario ...
BR,
Metod
 
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Madumi
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Re: cAP ac / v6.40.4 - frequent disconnects?

Tue Oct 30, 2018 2:55 am

While standards require quite low DC resistance of UTP cables and current of 0.5A through 30 feet of UTP cable should not cause too high voltage drop, use of sub-standard cables or non-perfect plugs and outlets or even oxidation could increase resistance of the PoE feed between ER-X and cAP ac to the point where voltage on PoEin porte of cAP ac would drop too low. I'd investigate this scenario ...
I've been thinking as much... the device seems to behave like it's not receiving sufficient power (even though the cables are decent cables). The setup is international (overseas from where I am), so I'll send through an auxiliary power supply & ask them to plug it in closer to the cAP ac... Will probably take a couple weeks & then I'll report back if it resolves the issue.

Thx!
 
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Madumi
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Re: cAP ac / v6.40.4 - frequent disconnects?

Sat Jan 12, 2019 12:23 am

Just an update that I upgraded the POE supply from 24v 0.5A to 48v 0.5A, and it's no longer disconnecting/re-booting.

Everything else seems to be working fine also, thx for suggestions!
 
anav
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Re: cAP ac / v6.40.4 - frequent disconnects?

Sat Jan 12, 2019 3:02 am

That is good news! Mkx is some kinda IT genius LOL
I'd rather manage rats than software. Follow my advice at your own risk! (Sob & mkx forced me to write that!)
 
mkx
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Re: cAP ac / v6.40.4 - frequent disconnects?

Sat Jan 12, 2019 12:10 pm

Sometimes my background (of being physicist) kicks in :wink:
BR,
Metod
 
anav
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Re: cAP ac / v6.40.4 - frequent disconnects?

Sat Jan 12, 2019 3:32 pm

Then we should talk more about physics LOL. One of my potential future son-in-laws is currently doing a masters in Physics and it makes for interesting dinner conversation.
I'd rather manage rats than software. Follow my advice at your own risk! (Sob & mkx forced me to write that!)

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