Wired Network Infrastructure

Ethernet Standards

IEEE 802.3 Ethernet is the dominant physical layer standard for enterprise wired connectivity. Current deployment-relevant Ethernet speeds and their primary use cases are summarized below.

For new installations, Cat 6A structured cabling is recommended as the minimum for access layer wiring. Cat 6A supports 10GBASE-T at the full 100-metre maximum channel length, accommodating future speed upgrades without recabling. Cat 5e is adequate for 1GbE but limits future upgrade options.

Structured Cabling

Structured cabling systems follow standards defined by TIA-568 (North American) and ISO/IEC 11801 (international). These standards define cable categories, connector types, installation practices, and test requirements. Compliance with these standards is a prerequisite for warranty coverage from cabling system vendors and for predictable network performance across the full channel length.

Telecommunications rooms (TRs) house patch panels, switches, and horizontal cable terminations. Typical TR sizing provides one TR per floor, serving up to 10,000 square feet of floor area. The horizontal cabling run from TR to work area outlet must not exceed 90 metres for permanent link, with an additional 10 metres allowed for patch cords on each end, for a maximum channel length of 100 metres.

Fibre optic backbone cabling connects TRs to the main distribution area (MDA). Multimode OM4 or OM5 fibre is the standard for intra-building backbone distances up to 150 metres. Single-mode fibre is appropriate for inter-building connections and backbone runs exceeding OM4/OM5 distance limits.

Power over Ethernet

Power over Ethernet standards defined in IEEE 802.3af (PoE, 15.4W), 802.3at (PoE+, 30W), and 802.3bt (PoE++, up to 90W) enable switches to deliver DC power to connected devices over Ethernet copper cable. Common PoE-powered devices include wireless access points (typically requiring 15–25W), VoIP phones (10–15W), IP cameras (10–20W), and IoT gateway devices.

PoE budget planning calculates the total power demand of all connected PoE devices and compares it against the switch's total PoE power budget. Switches are available with various PoE budgets; a switch with 24 PoE+ ports does not necessarily have a budget large enough to power all 24 ports simultaneously at full PoE+ power. Verify the switch's actual total PoE power budget and the average power draw of the connected device population, including projected device additions over the planning horizon.

Switching Hierarchy

Campus switching infrastructure is typically organized in a three-tier hierarchy: access layer (connects end devices), distribution layer (aggregates access switches), and core layer (provides high-speed backbone connectivity between distribution blocks). In smaller campus environments, collapsed core designs merge distribution and core functions into a single tier, reducing equipment count and complexity.

Leaf-spine topologies, common in data centre environments, are increasingly applied to campus networks. In leaf-spine designs, every leaf switch connects to every spine switch, providing any-to-any connectivity with a predictable two-hop forwarding path and eliminating the spanning tree complexity of traditional multi-tier hierarchies.

Redundancy Design

Network infrastructure redundancy provides continuity of connectivity when individual components fail. Access layer switches serving critical workloads may be deployed in pairs with dual-homed connections from servers and storage. Distribution and core switches are typically deployed in high-availability pairs with hitless failover capability. Building entry points should have redundant physical paths from separate telecommunications providers where campus criticality warrants it. Document redundancy design decisions and the recovery time objective for each failure scenario in the infrastructure design documentation.