@RendCycle 

They should be able to work on LAN only similar to the Tapo cameras.

Now, given your network, you have three different routers. If all those routers each have their own network segment (excluding the main one) then that may be why are not able to control the plugs when the internet is out.

With the internet, the plugs are able to be reached via the cloud, remote control doesn't care about your different routers. When the internet goes out, then you will need to connect to the actual router the plug is on.

So if you rP105 loess internet, connect to the ISP modem with your Tapo app, then see if you can control it.

Have you tried having router 1 and router 2 connected to the switch along with the ISP Modem and router 1/2 running in AP Mode?

@Tony 

Have you tried having router 1 and router 2 connected to the switch along with the ISP Modem and router 1/2 running in AP Mode?

The ISP Modem, which is the main Router connected to the Internet, is configured in "Bridge" mode to somehow avoid external DDOS attacks / Port Scans from trashing the device because the unit has low specs and have subpar security features. The Network is also intended to be separated in two. So I cannot use any of the WiFi Routers in AP nor Router mode as the ISP Modem constantly hangs/drops/slows down the Internet connection. This means I have to rely on the other newer WiFi Router I have for the Firewall for the time being until I find a better hardware... but I still kinda want to use my other old router for R&D purposes from time-to-time.

I only require ONE NETWORK SEGMENT to work at a time but I need to automatically turn on devices in Group A and C as scheduled and automatically turn off devices in Group B as scheduled. The WiFi Router in B is manually turned on together with pressing the corresponding button in the LAN Manual Selector when required so no need for it (turning on) to be scheduled through any smart plugs.

Anyhow, I found a minor mistake in the diagram I posted previously. But its just the illustrated diagram not the actual physical network connection. Here is the part I corrected to avoid confusion:

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Now, given your network, you have three different routers. If all those routers each have their own network segment (excluding the main one) then that may be why are not able to control the plugs when the internet is out.

With the internet, the plugs are able to be reached via the cloud, remote control doesn't care about your different routers. When the internet goes out, then you will need to connect to the actual router the plug is on.
 

So if your P105 loses internet, connect to the ISP modem with your Tapo app, then see if you can control it.


Please note that all Tapo plugs are not separated from each live network segment as long as a WiFi Router is turned on. All Tapo Plugs were added in both WiFi Routers using same SSID & Password though and expected to work in one network segment at a time since only one WFi Router is active at a given schedule. They should only change the network segment they use when the plugs and one of the Wireless Router turns back on as scheduled. So there is an "off" time period or a "break" wherein all devices are inactive. hmm... Do I need to leave at least one WiFi Router always "on" and the mobile phone with the Tapo App "on" too for this to work even if I will only want the plug's Schedule to continue working in that scenario?

The first test I did, which is the scheduling, I just checked if devices will turn off and turn on. Thus I connected the Mobile Phone with the Tapo App through WiFi Router 2 (Group B), which is turned on by default. This means all the Tapo smart plugs are connected to a single WiFi Router.

The test result for this: 

• Devices in Group A remained turned on. This should be the first to turn off as scheduled before Group B.
• Devices in Group B turned off as scheduled.

Since the WiFi Router 2 is still "on" and the plugs are all using the same connection, I thought the Tapo App and plugs will be able to communicate with each other because the Tapo App recognized them and are all reflected therein. They can also be turned on/off through the app when I tested them initially by pressing on/off button on the Tapo App itself for each plug using the same network set up.

The second test I did, was simply turning off devices in Group A (so Internet connection was turned off) through the connected Tapo App in my mobile phone by pressing on/off button (not testing the Schedule). I am connected to the WiFi Router 1 in Group C at this time as I left it continually turned "on" for this test. 

Test results:

• The Tapo App loses connection to all the plugs and shows inactive icons.
• Upon restarting the Tapo App on my mobile phone (which is still connected to WiFi Router 1 in Group C), I was prompted to log in to the Tapo Cloud. Since the Internet is down due to ISP Modem (Group A) being turned off, I was not able to access the Tapo App further and cannot control the plugs. Therefore, it led me to believe a live Internet is needed else how can I log in to the Tapo App? It needs to check the Tapo Cloud for log in authentication.

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To summarize my explanation, these tests were designed to work on ONE NETWORK SEGMENT at a time. To try and lessen the complexity, I just consider the Tapo Plugs to be connected to one (1) WiFi Router at a time (using similar SSID & Password) to control it through Local Area Network (LAN). That means the Ethernet LAN Cable connection should not be considered as were utilizing a Wireless LAN connection.

Do I need the Tapo Plugs and all other devices to be in one network segment only even if only one network segment is being used at a time?  For example only: Group B WiFi Router has IP Address 192.168.2.10 while Group C WiFi Router uses 192.168.1.10. All devices need to be either in 192.168.1.X or 192.168.2.X? I need to pick one only for the whole set up even if only one segment is expected to work at a given time?

If Internet is down due to the ISP Modem being turned off, the Tapo App in the Mobile Phone will not be accessible if you restart it as the user will be presented with a Login prompt to connect to the Cloud for authentication. If the user does not restart the Tapo App, the plugs will become inactive anyway and cannot be controlled through it.

I've made another test and I've confirmed: IF THE INTERNET IS DOWN, these smart plugs are inaccessible through the Tapo App even if  you have a WiFi Router turned on. What you can do only is to press the plug's buttons to manually turn it on/off. The plug's schedule will still work as long as there was no power outage that recently happened. But in my experience, there is a bit of a delay. That's it.

But I still haven't made another test by switching between 2 different WiFi Routers using the same Network Segment since the basic test did not pass my requirements. Will see if I can do it later.

Here are my test results:

• Using same network segment, these plugs were able to seamlessly be controlled using the Tapo App that can connect to two different Routers with similar SSID & Password. Of course, only 1 Router should be turned on at any one time.
   
• The schedules set for the plugs also ran fine as long as electric current flows through them continuously. Disruption will automatically turn off these plugs and any schedule set will just stop. If electric current then flows back into the plugs, pressing its button will turn them back on and any set schedule MAY continue depending on how long the offline period was. 
   
  • I noticed the Tapo P100 can stand longer offline time (max of 5-6 hours) so they can easily continue their schedule. 
     
  • The Tapo P105 loses their schedule after max. of 4-5 hours... or there may just be a longer delay. But I was not able to test that anymore. The schedules are still in the Tapo App though.
     
  • This means the Tapo P100 seem to be more stable as they have a newer firmware version. These plugs also fully supports the built-in Smart Actions feature of the Tapo App whereas the Tapo P105 does not.
     
• I just also want to note that there seem to be some considerations when using Power Strips with these plugs. I can only use a single Power Strip connected to a UPS for the Tapo P105. Using daisy-chained two Power Strips connected to a UPS, any set schedule for the plug does not happen.  
   
• When controlling/managing these plugs, an active Internet Connection and WiFi Router is required. But the set schedules for the plugs does not need Internet nor WiFi to run continuously. Having no Internet and WiFi for too long, more than 5-6 hours may delay the schedule and sometimes will need a reset (re-plugging to an electrical socket and pressing button). Electricity for both plugs is required else they will stop working and automatically turn off.

Is there any chance that the Tapo P105's Firmware will still be updated to support Tapo App's Smart Actions and receive same fixes as in the Tapo P100? I'm considering returning the plug and just replace it with a P100 which has a more updated Firmware and has less issues.

@RendCycle 

Thank you for the updated information regarding your issue, and I do apologize for the delay in response.

I will make an inquiry to our team regarding smart actions and the Tapo P105 to see if there are plans for smart actions to be implemented.

@Tony Thanks. I was able to work with two Tapo P100s for now and still deciding what to replace the Tapo P105 with. I hope they really should upgrade the Firmware for that model so it can work similarly with the Tapo P100. But it would be great if the LAN Control feature be clarified if actually existing or not because all three of these plugs, as I tested, cannot be accessed through just WiFi. They require an Internet connection to be able to be managed through the Tapo App.

@RendCycle 

From the information, I got the ability to access the plug while being on the same LAN applies to all Tapo devices so all cameras and plug types. If you are seeing otherwise I would recommend reaching out to our support team.

Also regarding the smart actions that those are also available as well to the Tapo P105. I do not have one on hand, however, I would recommend reaching out to our support as well. I think something may be getting overlooked.

@Tony , thanks for the reply.

I've already refunded the Tapo P105 but have bought two more Tapo P100. Tested all four Tapo P100 and they behave similarly. If there is NO INTERNET connection (even if I still have WiFi), these plugs cannot be accessed through the Tapo App. Therefore they cannot be managed/controlled. I have to have both active Internet connection and of course the WiFi Router turned on so I can log in and access the plugs through the Tapo App.

For the Tapo P105 (1.2.10 Build 20200609 Rel. 33394 firmware), I can confirm they don't support Smart Actions and I remember there was a message in the Tapo App indicating that the feature support is "coming soon".

How do I contact Tp-link tech support who will reply? I tried sending email to my country's Tp-link tech support email address in the past but received no reply.