Which protocol is primarily responsible for routing packets across interconnected networks?

The Internet Protocol (IP) is the primary protocol responsible for routing packets across interconnected networks. It is a fundamental component of the Internet Protocol Suite, which provides the means for communication over a network. IP is tasked with addressing and forwarding packets of data from the source to the destination through various intermediary devices and networks.

This process involves encapsulating data into packets and assigning them source and destination IP addresses, allowing routers and other network devices to determine the best path for the packets to travel. IP is designed to work in an environment where networks and hosts may be heterogeneous, meaning that different types of hardware and networking technologies can coexist and communicate effectively.

The other types of protocols mentioned serve different purposes. Application protocols deal with end-user interactions and data formats, security protocols focus on protecting data integrity and confidentiality during transmission, and network protocols encompass a broader range of protocols that can include IP but also cover other functions related to network operations.