I saw the problem on my topology page.   I expect to see entire my network, i mean all of my devices (all switches and APs).   But for some devices, it disappears from the topology page. then i check on the switch port, the point that these devices disappear, all of these run cdp/lldp normally and i can see these devices connect with switch port normally.   Even so, on topology page still not show these devices.       P.S. disappear devices are C9300-48UN, CW9164I ... View more

Hi @Tony-Sydney-AU    Because it's the access-control devices. Them working like a passive mode right? These devices look like not sent any communication activity. I saw only ARP packet when i sniff the packet. Maybe reason why it's always show offline state right? **i'm not yet testing sniff packet when scan card before.   What do you think about this?     ... View more

Hi @Tony-Sydney-AU,   These devices connected by the cable. Almost devices that show offline are access-control. I'm not sure it's maybe sleep mode, energy saving mode or not.   That is good point. i will check it with support team of these devices.   Many thanks, ... View more

Hi @KH   Yes, I saw them offline longer than 5 minutes. These devices should be always online, their never power-off for sure. For "Last seen" timestamp is longer than 5 minutes too. ... View more

Alright, I got it. Many thank @Ryan_Miles . ... View more