OBI2182 drops off LAN when Laptop shuts down (Resolved)

[Vermonter]

This is weird.  I've looked (and searched) the forums so apologies in advance this is already resolved or has a FAQ or something.  I've requested help from Poly customer care but they're blaming my LAN without offering any real suggestions.

Situation:

I have recently bought two OBI2182 to replace a couple of Obi200 and (old) Polycom POTS speaker phones.  The 2182's are running Software version 6.2.3

The phones works perfectly until I shutdown or suspend my laptop (a Thinkpad X1 Carbon running Kubuntu 21.04). Then they drop off my LAN and stay off until I power cycle the units. (I.e., I can't ping them nor connect to them via my browser, a soft reboot doesn't help).   Powercycled they work great until the next time my laptop shuts down.

I've fixed the DNS servers to 8.8.8.8 & 8.8.4.4 to no effect. The phone is configured to use Google Voice & 12VoIP, obviously both become unavailable when the phone drops. I also tried fixing the Switch Port 1 Speed to 100 AUTO, also to no effect.

One of the phones is connected to and powered by a Netgear GS305P switch (which my laptop is on). The other is on a different LAN segment and powered via its own adapter.  Since it drops at the same time my desktop switch is presumably not the culprit.

Anyone seen this or have a fix?

Thanks.

[Sheffield_Steve]

The only conclusion I can come to is that your laptop is the source of the internet.

e.g. The laptop connects to the internet via wi-fi and the switch/Obi is getting internet via the laptop. (Maybe via a docking station?).

A simple way to test would be to switch off the wifi on the laptop and see if the OBi looses connection.

[Vermonter]

Turned off wireless on the laptop, phone is unaffected.  The laptop uses a wired connecting when I'm at my desk (its attached to the same ethernet switch as the phone).  Also, the phone boots up just fine when the laptop is turned off and continues to work after the laptop boots up itself...until I shut the laptop down.

I haven't configured the phone's WiFi interface.  Checking on my router (a Netgear R8000 running DD-WRT) the MAC address for the phone is the wired one shown on under the phone's "Product Information" button.

Thanks for the suggestion though.  It sure feels like something at the Ethernet level, but I've tried swapping cables and the two phones disconnect simultaneously but are connected to different switches (though on the same LAN).

Thanks for the suggestion though!

[Sheffield_Steve]

Does the phone work if you disconnect the laptop from the switch?

[Vermonter]

Good suggestion!  Unplugging the laptop's ethernet cable without shutting down doesn't seem to have brought down the phones...but plugging the ethernet cable back in did.

However, yes they worked fine after I unplugged the laptop and powercycled until I reconnected the ethernet cable.

Absent another suggestion I'll try running without wired ethernet (gah) for a few days and see if the phones are stable.

[SteveInWA]

This sounds like you have a bad Ethernet cable or port on your ThinkPad.  Your "use WiFi on the laptop instead of Ethernet" test should determine if that's the case.

[Vermonter]

On the off chance that someone else runs into this I'll document the situation and resolution.

Hardware:  Thinkpad X1 Carbon 6th Gen.  Lenovo Thinkpad Thunderbolt 3 Dock. 
Operating System:  Kubuntu 21.04
Was using the Ethernet port on the Dock to connect to first a TP-Link 5 Port Gigabit Ethernet Network Switch (TL-SG105) and then a NETGEAR 5-Port Gigabit Ethernet Unmanaged PoE Switch (GS305P).  Same problem independent of the switch.

Notably, I've been using an OBi200 for years with no problems.  Switched to an OBi2182.  As indicated earlier in the thread the OBi200 worked flawlessly.

Shutting down the laptop would cause my phone to go completely offline.

In the end I found that using different Ethernet adapter "fixed" the problem.  I grabbed a Cable Matters USB3 to Ethernet adapter (model number 202013) and have essentially the same network throughput without the problems with the phones.  Given that the adapter is about $15 I've decided to call it a "fix" though the original problem is still unresolved.  I've about a dozen other devices on my LAN, none of which had any issues, so I'm putting this down to some weird interaction between the driver for the Ethernet chip and this specific phone.

Thanks to SteveInWA and Sheffield_Steve for their input & clues.

[SteveInWA]

Was using the Ethernet port on the Dock to connect to first a TP-Link 5 Port Gigabit Ethernet Network Switch (TL-SG105) and then a NETGEAR 5-Port Gigabit Ethernet Unmanaged PoE Switch (GS305P).  Same problem independent of the switch.

There's your problem.  I haven't used your particular model of Thinkpad dock, but "back in my day", there was a problem with the docks causing problems like that.

It's a bad idea to put the dock ahead of the rest of your network-attached equipment.  Put the dock on the switch like everything else.