13.7 LOOKING AHEAD

This chapter has focused on how information is transferred within individual communication systems and how users gain access to those systems. However, modern communication rarely occurs within a single isolated network. Instead, billions of devices communicate across vast collections of interconnected networks spanning cities, countries, continents, and even space.

This raises a new set of questions that extend beyond switching alone:

How are communication networks organised?
How are network devices interconnected?
How are addresses assigned and interpreted?
How are routes selected between distant destinations?
How is traffic managed when demand exceeds available capacity?
How is reliable communication maintained across many intermediate nodes?
How are independent networks interconnected to form the global Internet?

These questions form the subject of networking, which is explored in the next chapter. There we examine network topologies, routing principles, layered protocol architectures, and the fundamental concepts that allow complex communication networks to operate efficiently despite their enormous size and diversity.

Beyond networking lies the broader challenge of internetworking: connecting independently designed networks into larger communication systems while preserving interoperability, scalability, reliability, and security. The Internet is the best-known example of such an internetwork, demonstrating how millions of individual networks can function as a single global communications infrastructure.

This chapter therefore completes the transition from individual communication techniques to communication system architecture. The chapters that follow build upon this foundation by examining how communication networks are organized, how they exchange information efficiently, and how they support the mobile, wireless, satellite, and cloud-based services that define modern digital communications.