@TD-W896 TD-W8961N is not supported by the tether app.

@AR3000 This is a known issue when using WDS feature of a wireless router - its WAN port is not used, hence "No Internet Connection" message. If it's about the router FW updates you can alway install...

@Ironicster A common wireless router would do the job. Keep in mind that the devices behind the second (private) router would be able to see the devices behind the main router - the oposite would not...

@Ranibarhama Refer this thread regarding your question.

@itachimetal This is implemented into the device FW and can't be disabled. Here's a more detailed description of the online check mechanism.

@Muzza54 Both would do the job. Here's a comparison between those two for better view.