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Xsaron
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CRS125-24G-1S random port flapping on different interfaces on multiple switches

Wed Feb 27, 2019 12:27 am

Hello
I have the following network set up in multiple buildings. The buildings are 'student homes' with end user numbers varying from 7 to 24 depending on the location. We only offer them a LAN connection on a shared internet line.The students sometimes connect their own wireless router (eg. linksys/d-link/tp-link... the LAN from the building is then connected to the WAN input of the wireless router) if they want to have a wifi connection.
Image
For a while now we're experiencing a strange phenomenon on the CRS devices and this at several locations, while the issue seems to be occuring at random.
There would be x devices online and each connected to an interface on the CRS when suddenly the switch decides to change the status of an interface to 'link down' and a few seconds later again 'link up' (sometimes with a different speed, but most of the time it remains the same), this happens on several interfaces and appears to be random. It definitely comes down to the CRS because using other cables or devices doesn't change the behavior. When I connect the devices to another network device (eg. directly to the RB2011), the connection is long term stable and no reconnects occur.
The CRS is always on the latest stable release, the problem persists for more than a year now but I never had time to post it here on the forum, so the issue existed with different firmware versions.
Part of the log:
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I also notice that in the interface overview sometimes all connections suddenly drop to 0 bps simultaneously for a fraction of a second and then everything just continuous as it was.
I couldn't catch the screenshot at the exact moment though, the outer right colums would jump to 0 for a very very short time. This happens only a very few times luckily but it shouldn't.
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Any ideas about what is going on here? This is really unstable...
I would appreciate the help!

As it occurs on multiple locations, so multiple CRS-devices, I would assume that OR it's due to a software issue, OR a configuration issue
Last edited by Xsaron on Sat May 18, 2019 10:58 am, edited 1 time in total.
 
Xsaron
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Re: CRS125-24G-1S frequent reconnects on different interfaces on multiple switches

Thu Feb 28, 2019 12:51 pm

Anyone? This is a really anoying issue and I can't find the cause.
 
grusu
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Re: CRS125-24G-1S frequent reconnects on different interfaces on multiple switches

Thu Feb 28, 2019 2:07 pm

Try to change the power adapter.
 
Xsaron
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Re: CRS125-24G-1S frequent reconnects on different interfaces on multiple switches

Fri Mar 01, 2019 1:16 pm

Ok, I will try that. Any other suggestions in the meantime? Perhaps someone had the same experience once?
 
Xsaron
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Re: CRS125-24G-1S frequent reconnects on different interfaces on multiple switches

Mon Apr 08, 2019 4:16 pm

Hi; tried but failed. It's also not caused by the cabling because I tested it now with the same switch in another building, same issue. Switch broken?
 
Xsaron
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Re: CRS125-24G-1S random port flapping on different interfaces on multiple switches

Sat May 18, 2019 11:00 am

So. It's not the power adapter, it's not the cabling, it's not fixed with a firmware upgrade...

Any other suggestions? I could try to do a factory reset but I prefer not to.

When port flapping I see that different speeds are negotiated, seems to me like a bug with the auto negotiation implementation?

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