I read the following article and watched below video.
https://www.youtube.com/watch?v=Ug8NH67_EfE
On those media, they say that payment channels are based on just TCP/IP connection (unicast) not p2p.
In Lightning network's white paper, there is no explanation of what method is used to establish payment channel between two nodes.
What method is used for establishing payment channels ? traditional TCP/IP way or p2p ?