Instabilities with GS1200-8 managed

ODuis
ODuis Posts: 8
edited August 2022 in Switch
Simple setup, the Zyxel as switch for PCs and printers behind a very very commonly used internet router. Latest firmware (also tried one version before).

Some instabilities:
1. the crucial port with the modem will just sporadically connect with 1GB. It often connects with just 100M. A PC connected directly to the modem always connects with 1GB, so it looks like a Zyxel problem.

2. Some ports randomly seem to be down espc. after e.g. reboots of two PCs. Already disabled all power management features, but no luck. Re-powering the Zyxel solves the problem. Latest drivers on PCs of course.

Is mine a defect one, or is this reliability level common in this price range?
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All Replies

  • PeterUK
    PeterUK Posts: 3,500  Guru Member
    100 Answers 2500 Comments Friend Collector Seventh Anniversary
    Is it a ISP router your using?

    Bad cable? use CAT 6

    Can you ping from a device on the switch to another device on the switch fine? 
  • ODuis
    ODuis Posts: 8
    edited June 2021
    Hello Peter,

    Yes, an ISP router from german telecom (Speedport Smart 3). Distributed as plain but reliable workhorse.

    Pings from the PCs to the central router as well as to e.g. the printer connected to the switch are very fast and have 0% loss rate. Internet works fine. Just sporadic instabilities as described above.

    PS: Cable from switch to router is a 25m Cat 5e cable (enough for Gigabit). The other devices that have sporadic problems looking like not being connected to the switch have different, shorter patch cables.

    Oliver
  • PeterUK
    PeterUK Posts: 3,500  Guru Member
    100 Answers 2500 Comments Friend Collector Seventh Anniversary

    Is this 25M cable tested with a PC for no packet loss over time and does not drop you to 100Mb?

    Can you try shorter cables from router to switch to device.

  • ODuis
    ODuis Posts: 8
    I tested the ping with switch and 25m as well as with directly 25m with PC. No packages loss. Ping times just a few ms.
    I'll try to disabled some advanced switch features. It should be unrelated, but I heared that some switches are a bit buggy, so stripping advanced features sometimes works miracles on some models.
  • Zyxel_Adam
    Zyxel_Adam Posts: 430  Zyxel Employee
    Zyxel Certified Network Administrator - Nebula 25 Answers First Comment Friend Collector
    Hi @ODuis,

    Welcome to Zyxel Community.

    Regarding your issue, we strongly recommend you to change a cable to see if the link speed issue still exist between ISP modem and GS1200-8. I understand that you've tried to do ping testes between Router, switch, and PC, and the Cat 5e cable works well. 

    However, 0% packet loss does not guarantee the quality of cable.
    Therefore, please help us to use a cable (shorter is better) to test again.



    Adam

  • ODuis
    ODuis Posts: 8
    Its not a cable problem, like I said, it had trouble with several devices connected through different cables. The router connection was just one of the problems.
    However I found that switching off all advanced features on the Zyxel seem to have solved the problem.
  • mMontana
    mMontana Posts: 1,399  Guru Member
    50 Answers 1000 Comments Friend Collector Fifth Anniversary
    @ODuis what do you mean for "advanced features"?
  • ODuis
    ODuis Posts: 8
    I switched off flow control, IGMP snooping and port based QoS. Now it's a pretty plain switch, but it seems to be stable.
  • Zyxel_Adam
    Zyxel_Adam Posts: 430  Zyxel Employee
    Zyxel Certified Network Administrator - Nebula 25 Answers First Comment Friend Collector
    @ODuis

    Thanks for your reply.
    Kindly inform you that try not to use Flow Control on uplink port(to your ISP router) of GS1200 switch.
    It may cause the issue you had before.
    Configure IGMP snooping and QoS should be fine.

    Adam

  • ODuis
    ODuis Posts: 8
    Thanks Adam, that was my first suspect, too. But it switching it off alone did not help it seemed.
    My next suspect is the port based priority (gave more priority to the router an the laptops, less to the printers), so I'll try to enable IGMP Snooping to see it that is ok.
    Might be a weired issue in feature combination, or one of my devices that does not play nice in the network causing this trouble.

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