josey_adm1n_sp wrote

The question is: Is it possible that switches like TP-LINK TL-SF1005D or TP-Link TL-SG105 or TP-Link TL-SG108 get into hibernation mode after several hours without activity and therefore do not transmit packets after re-starting ?

Kind of. Those switches turn off idle ports for energy management. But I would say the design fault is with the NAS, which almost certainly puts its own port into idle state due to hibernation mode and therefore causing the switch to turn off the port, too. IMHO the NAS should not put its interface into idle state if it expects to be woken up by receiving data on this port.

josey_adm1n_sp wrote

I think the cause of the lost packets is that the ARP tables of the switch are flushed after several hours of inactivity.

The ARP table is flushed after expiration time has passed, even if packets are being transmitted, thus causing another ARP request. The ARP table is not related to the switch's CAM table, where MAC addresses are stored in. In almost any switch I know the ARP table has no awareness of the port's state. If a port goes down, the MAC table entry will be flushed from the CAM, but this table is not tied to the ARP table, so entries in the ARP table still exist until expired.

So, the ARP table entries also expire during normal mode and will need to be refreshed anyway. Why should this not work if the switch is in a mode for energy saving? Reduced power mode does not mean that it permanently disables a port.

I have only three types of devices which use hibernation mode and they behave differently on my TL-SG2008 switch: a network printer and a MacBook keep the ports up and running during hibernation, while a thunderbolt station from CalDigit causes the port's mode to go back to 10BASE-T during deep sleep mode of the MacBookPro connected to it. As soon as I wake up the MBP, the CalDigit's port will go back to 1000BASE-TX mode again. Maybe it does this to ensure I could use Wake-on-LAN (WoL) on the MBP but I don't need WoL for it. On the network printer I disabled the sleep mode just for the network interface, so that WoL correctly wakes up the printer if in sleep mode. I can even use the web UI of the printer if its print engine and the raster image processor is in deep sleep mode.

Just out of curiosity: what NAS system do you have?

I can only tell you that my Kyocera printer using Wake on LAN (WoL) has two different hibernation modes for its Ethernet network in the EU version:

1) An EU-regulatory-conforming mode of "deep energy saving" not working with WoL
2) and a non-EU-conforming mode of "no deep energy saving" needed to work with WoL on any type and brand of switch.

I had to choose mode 2 to be able to wake up the printer on network traffic. In mode 1 WoL didn't work (even not with a 10-year old switch).