NonEthernet

NonEthernet refers to networking technologies and practices that do not rely on the Ethernet family of standards, notably the IEEE 802.3 specification. The term is used descriptively rather than as a formal standard, encompassing a range of historical and contemporary alternatives to Ethernet for local area networks, storage networks, and high-performance interconnects. It includes legacy LAN technologies such as Token Ring (IEEE 802.5), Fiber Distributed Data Interface (FDDI), and ARCNET, as well as non-Ethernet interconnects used in specialized environments.

Historically, nonEthernet solutions arose to address specific limitations of early Ethernet, such as deterministic access, higher reliability, or greater bandwidth at particular scales. Token Ring used token-passing access, while FDDI offered ring topology over fiber for backbone networks. In storage and data centers, Fibre Channel provides a dedicated storage area network with its own framing and addressing, and InfiniBand offers low-latency, high-throughput interconnects for HPC and data-center workloads. These technologies were often chosen for reasons of QoS, performance guarantees, or compatibility with legacy systems.

Key characteristics of nonEthernet networks include distinct framing, addressing, and access methods that differ from Ethernet. For example, Fibre Channel frames differ from Ethernet frames, and InfiniBand employs a different message-passing model. Some non-Ethernet networks use fixed or specialized topologies and require gateways or protocol converters to interoperate with Ethernet networks. While Ethernet dominates modern LANs, nonEthernet technologies remain in use in niche applications and legacy environments.

In contemporary contexts, nonEthernet technologies are mainly found in storage networks, high-performance computing, and certain legacy installations. They continue to inform design choices and migration strategies, particularly in mixed environments that interface with Ethernet-based networks.