SG300-10PP (and SG300-48PP) switch reboot problem

[Jure Erznoznik]

I have several Android tablets connected to the mentioned switch, all being powered by it.

However, if I restart the switch, many (or all) of them will wake up and not be able to obtain their IP addresses via DHCP (the switch is NOT the DHCP server).

I'm guessing the switch wakes up its powered devices sooner than it is capable of actually switching ethernet traffic. Please note that the tablets themselves take about a minute to boot up and the switch takes about half a minute before it supplies power to the first of them.

Is there a setting in switch that would allow me to increase the time before switch starts supplying power on boot?

[Flavio Miranda]

Hi,

 I doubt there's something like that on switches, even fancy one.

 I'd suggest some simple script on Android performing dhcp release. Or even easier, put a very very long lease on your DHCP so that Tables need not get IP very often. 

[Jure Erznoznik]

This is not the issue: the switch is not off for any extended time. No DHCP lease would expire during this time. The problem is that devices make the request upon booting and the request goes nowhere.

[Flavio Miranda]

I may not understood this correctly. If your problem is the DHCP request fail while switch reboot, why my suggest does not work?

[Jure Erznoznik]

Your suggestion does not work because I have Android tablets here: they boot and end up with non-connected IP stack. Reestablishing the IP stack would require root access.

[Flavio Miranda]

Alrigh, You know the environment better then me. I though that as your problem is the reload process then a longer DHCP lease time could prevent clients from renewing the AP address very often, then, avoid this situation. You cound even put status IP address if possible.

[Jure Erznoznik]

I have further information on the problem:

The tablets will NOT get a DHCP lease in this scenario:

1. Disconnect the switch from its upstream (so that the switch does not have internet connection)

2. Reboot the switch

3. Reconnect the switch's upstream at any time after the reboot command has been executed.