Why Switches Are the New Computing Backbone: Definitions, Architectures, and Market Trends

Global Market Overview

According to IDC, the worldwide switch market reached 308 billion CNY in 2022 (a 17.0% YoY increase) and is projected to grow to 322 billion CNY in 2023 and 377 billion CNY by 2027, with a CAGR of about 4.6% for 2022‑2027. China accounted for 19.2% of the global market in 2022 (591 billion CNY) and is expected to reach 645 billion CNY in 2023 and 878 billion CNY in 2027.

Switch Definition and Classification

A switch (or “switch”) is a network device that forwards electrical or optical signals, providing dedicated communication paths between any two connected nodes. Common types include Ethernet switches, telephone voice switches, and fiber‑optic switches.

By OSI layer: Layer‑2 (MAC‑based), Layer‑3 (IP‑based, sometimes with Layer‑4 capabilities), Layer‑4 (port‑based), and application‑level switches for data‑center use.

By network tier: Access switches (high port density, 10/100 Mbps), aggregation (core) switches (modular chassis, high back‑plane capacity), and distribution switches (mix of access and core functions).

By application area: WAN switches (carrier‑grade, multiple ports with bridging), LAN switches (office/enterprise).

Hardware Composition

Typical hardware components are chassis, power supply, fans, backplane, management engine, system controller, switching modules, and line cards. The management engine provides a serial console for configuration; the system controller manages power and cooling; line cards host Ethernet interfaces; switching modules contain high‑performance ASICs for packet forwarding.

Switch Architecture

Three mainstream architectures are Full‑Mesh, Crossbar, and CLOS, with most high‑end core switches adopting CLOS.

CLOS‑Based Switch Board Designs

Non‑orthogonal (parallel) design: Line cards run parallel to the switch fabric on the backplane; used by Huawei. Drawbacks include signal interference, limited bandwidth upgrades, and challenging heat dissipation.

Orthogonal design: Line cards connect vertically to the switching module via the backplane, reducing signal loss but limiting bandwidth upgrades; used by Cisco.

Backplane‑less design: Direct vertical connection between line cards and switching modules, eliminating backplane bandwidth limits and improving cooling.

Technical Principles

Switches operate at OSI Layer 2, maintaining a MAC address table that maps each MAC to a specific port. When a frame arrives, the switch forwards it only to the destination port, reducing broadcast domains while preserving collision domains. High‑speed backplane and internal switching matrix enable simultaneous multi‑port data transfers, effectively providing each port with its own bandwidth.

Comparison with Hubs and Routers

Unlike hubs, which broadcast incoming frames to all ports, switches forward frames selectively based on MAC tables, preventing unnecessary traffic. Routers connect distinct networks and operate at Layer 3, using IP routing tables, whereas switches focus on Layer 2 forwarding.

Performance Metrics

Data‑Center Switches

Traditional Three‑Tier Architecture

Consists of access, aggregation, and core layers. Access switches connect servers; aggregation switches interconnect access switches and provide services (firewall, SSL offload, IDS); core switches provide high‑speed forwarding across VLANs. Limitations include bandwidth waste due to STP blocking, large fault domains, poor scalability for massive networks, and high cost for high‑port‑density equipment.

Spine‑Leaf (Leaf‑Spine) Architecture

Also known as a distributed core network, it is a CLOS‑based design where leaf switches aggregate server traffic and connect to spine switches that form a full‑mesh. Benefits include flat topology (low latency), easy scalability (add spines or leaves as needed), low convergence ratios, and suitability for multi‑cloud environments.

Industrial Switches

Designed for harsh environments (temperature extremes, electromagnetic interference, salt fog, vibration). They use TCP/IP over Ethernet, support high‑speed (1 Gbps, 10 Gbps) links, and include intelligent alarm systems to ensure reliable operation in factories.

Industry Supply Chain

Upstream components: chips, passive components, optical modules, PCBs, power modules, chassis. Midstream: unmanaged switches, Layer‑2/3 managed switches, PoE, industrial and data‑center switches. Downstream: telecom operators, cloud providers, data‑center operators.