Fusion of Network Technologies

The physical distinctions among Local Area Networks (LANs), Metropolitan Area Networks (MANs), and Wide Area Networks (WANs) based on geographic scope and underlying media (e.g., Ethernet, fiber optics) are likely to remain. However, a significant fusion is already happening at the logical and management layers. This convergence is driven by several factors:

• Software-Defined Networking (SDN) and SD-WAN: These technologies decouple the network control plane from the data plane, allowing for centralized, policy-driven management across diverse network segments. This enables consistent application of policies and routing decisions from the LAN to the WAN, making the traditional boundaries less relevant for network operations.
• Virtualisation and Cloud Computing: Resources and services are increasingly hosted in data centers accessed over WANs (i.e., the Internet), but from an end-user perspective, they behave as if local. This blurs the line between accessing a local server and a cloud-based application.
• Virtual Private Networks (VPNs): VPNs establish secure, logical connections over public WANs, extending the reach of a private network. This allows remote users or branch offices to connect to a corporate network as if they were physically on the LAN. Principles related to secure network extension are discussed in general network security texts, such as Joseph Migga Kizza's Guide to Computer Network Security.
• Ubiquitous IP-based Internetworking: The Internet Protocol provides a universal framework for addressing and routing across all network scales, enabling seamless communication and service delivery regardless of the underlying network type.

These trends indicate a future where network management and service delivery are increasingly unified, abstracting away the physical distinctions of LANs, MANs, and WANs from an operational perspective.