Zyxel GS1900-24E. Ports / links periodically go to "down" mode

Yuri_S

Good day
I have two identical switches - Zyxel GS1900-24E. Firmware version for both of them is V2.40(AAHK.1)_20180705 | 07/05/2018. Both switches work OK, but I detected strange behaviour is syslog.

Some used ports (links) go down for few seconds and after return back in up mode.

Device that connected to this port is simple Windows-based workstation. I has installed antivirus and I confirmed that no any malwares exist on it.

Also there are no any loops and errors on switches

and as you can see no any events in syslog with the severity higher than "notice"

Second switch has similar symptoms:

and also no any errors / loops exists

My question is - how can I investigate given issue? I'm not sure that this is normal behavior.

Thanks in advance.

Zyxel_JonasTan

Hi @Yuri_S,

Thanks for the information.
Based on the status more like a link flapping, please help to verify if there is CRC error on port 9.

Steps:
1. Access GS1900-24E via webUI.
2. In this page, check if there is counter on "etherStatsCCAlignErrors". If yes, the issue is related o layer 1 (physical issue), try to change the network cable then observe if the issue resolved.
Monitor > Port > Port Counters


Thanks for supporting Zyxel!

Yuri_S

Good day,

seem issue was in weak patch cable. I just replaced it with good one and everything is OK now.

Many thanks for your help

Zyxel_JonasTan

Hi @Yuri_S,

Thanks for the information.
Based on the status more like a link flapping, please help to verify if there is CRC error on port 9.

Steps:
1. Access GS1900-24E via webUI.
2. In this page, check if there is counter on "etherStatsCCAlignErrors". If yes, the issue is related o layer 1 (physical issue), try to change the network cable then observe if the issue resolved.
Monitor > Port > Port Counters


Thanks for supporting Zyxel!

Yuri_S

Good day,

seem issue was in weak patch cable. I just replaced it with good one and everything is OK now.

Many thanks for your help