Is it possible to construct a connection oriented and connectionless architecture in a single network?
Yes. However, if you setup a connectionless architecture (by which I imagine you mean that you want to write some sort of server application), you’ll need to make sure that the packets reliably get to the receiving end in the intended order. The two most popular connectionless protocols in the TCP/IP suite are UDP and IP. TCP is a connection-oriented protocol, so it ensures that the receiving end knows what order the packets are received, and it has a handshake protocol to ensure that the initial connection is received and shut down correctly, which ensures that the data reliably gets to it’s intended recipient. TCP also has support for error detection, and if it detects a problem will re-request the packet that was corrupted.