TCP/IP is a suite of communication protocols that defines how data is transmitted and formatted so that network devices can interconnect on the internet. It features end node verification to ensure successful data transfer and dynamic routing to allow end nodes to transfer data over multiple paths and choose the best path. TCP/IP has four layers - application, host-to-host transport, internet, and network access - that work together to transmit data in packets from bits. It solves problems related to addressing, routing, naming, and flow control.