I thought IPv6 and TCP could be used independently, but IP does not need TCP at all, whereas TCP usually needs IP to function. Is my understanding correct? Does IPv6 need TCP to function? Looking at the OSI layer descriptions it appears that internet protocols (IP) belong to layer 3 and the transport layer (e.g. TCP) is layer 4 so my interpretation would be that the two can used independently. Still, the internet protocol will not fail if TCP fails, but normally TCP would fail if the internet protocol fails, but TCP could rely on some other addressing than IP (?) and still work.
I read in an answer here that "you can use different transport protocols (TCP and UDP) with the network layer, IP." but surely it would not be feasible or any idea to "use IP with TCP", meaning that "IP uses TCP to function", or I'm not sure what the later statement would imply.
