Hi,
Not directly related to the openwrt, but since this forum is full of networking experts and enthusiast, and my network is comprised of 2 openwrt devices, let's give it a try:
Sony BDV-N9200W is a old school blueray player/ home cinema avr that I have plugged in to a unmanaged gbit switch.
This sony actually runs on some embedded linux, as I can see in software license info list of linux packages like busybox, linux-kernel and many more. too bad I don't have root access, all of this could be avoided.
The bizzare issue is, sometimes when I wake up this device from sleep (it goes to some power saving state, but still responds to ping and can be awaken via network - I have it controlled by openhab - smarthome platform.) it does something to the network switch its plugged into, maybe some broadcast, some udp traffic, maybe something related to those stupid home streaming protocols, DLNA, SSDP etc...and basically the entire network is down, cannot access any device anymore until I unplug that device from the network. sometimes, I even have to restart that switch.
I found many cases like that online, with Smart TVs and other similar devices, nobody has a solution other then try to move it to wifi, try setting a static IP, try factory reset, this and that
Is there any way I could prevent it from killing the network, like drop all traffic except TCP communication to a single IP? Or, because its connected to a unmanaged switch (which is connected to openwrt router switch port), it will kill that switch regardless of my openwrt rules?
What if I configure it's IP manually and leave default gateway empty? again if its flooding some broadcast, probably it doesnt care about gateway?
Because this is quite off topic for OpenWrt, it really belongs on a more general site.
There is nothing that OpenWrt can do to resolve this issue, since there aren't any configurations that could fix it except maybe putting the device on its own dedicated subnet. Or... a business grade managed switch should be able to shut down the port when there is unusual behavior/activity like broadcast storms or spanning-tree-protocol related issues.
That said, I would check to make sure that it is only connected to ethernet and that it is not connecting to wifi at all. I've seen situations where the wired and wireless connections are bridged instead of being treated as separate interfaces. A bridge with both active will cause a switching loop.
If that doesn't help, I'd recommend asking on a more general site.
As mentioned, there isn't a whole lot you can do, before having found what the device is doing.
What often happens though, is packets being 'reflected', creating a self-accelerating feedback loop, which will break down the network (at least the broadcast address). If this is the case, and in the absence of firmware updates fixing it, hardware replacement should be considered.
Other options include:
taking it off the network
I realize bluray can't be taken completely offline, but maybe at least most of the time (only under controlled circumstances)?
putting it into a dedicated 'guest' network, directly to one of your router ports (or a managed switch with VLANs.
key aspects here, routed not switched and physically isolated from your normal lan and its broadcast domain (it will still kill this network, but at least your lan keeps working, to some extent).
But all of this still papers over severely broken hardware, that simply is defective and should be thrown out.
(It happened to me with a switch in the past, which started reflecting packets while being powered off - once I realized what the issue was, it went to the landfill immediately).
thanks for suggestions.
Since I realized this happens only after awaking from sleep, never after a clean full boot (which can be achieved by power cycling, or disabling sleep state), I tried to use it with disabled sleep, but unfortunately it does not support WOL, so I cannot remotely power it up from full shutdown state.
One ugly workaround is to just keep it always on 24/7, even though it's wasteful and not aligned with home automation philosophy and scenarios (bring everything down when you leave the house, power up when you are back, etc)
Other would be to try the wifi, and see if it can be awoken from the wifi interface.
Third would be to take it completely down from the network and control it with IR blaster.
Generally I agree with you, this broken crap is really annoying and should be thrown out of the house, but that drags out 5 speakers, one mini amp for rear speaker that connects via some proprietary wireless to the main amp, and a subwoofer with it. So I will try to work around it for now...
Unfortunately, due to position and cabling restraints, it cannot be connected directly to the openwrt port, as I have only 1 trunk (patched through the walls) from the unmanaged switch to the router.
It sometimes happens that two ethernet ports hate eachother, firmware updates on both sides can help. Id take the isdue with your crap switch vendor first. Nothing indicates OpenWRT is affected here.
I've moved the device to wifi and wake over WLAN works, so if it will not cause any havoc on the wifi networks, it stays there.
I actually replaced the dumb switch as I accused it for the havoc before realising who was the real culprit. I might have thrown a perfectly working switch to the garbage...