100 Gigabit Ethernet (100GbE) is Ethernet operating at a nominal data rate of 100 gigabits per second. The name identifies a speed class—not a particular cable, connector, optical transceiver, or maximum link distance. Those physical details depend on the selected Ethernet physical layer (PHY) and the equipment at each end.
What does 100GbE mean?
100GbE uses Ethernet’s common Media Access Control (MAC) specification at a nominal rate of 100 Gb/s. IEEE describes Ethernet as operating at selected speeds from 1 Mb/s to 400 Gb/s under a common MAC specification and management information base (MIB), with PHYs for particular speeds and media. IEEE 802.3-2022 overview
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The MAC governs how Ethernet frames are handled; the PHY encodes and decodes signals for a chosen link implementation. Consequently, two devices both described as 100GbE still need compatible physical interfaces and a suitable link medium.
What cable or transceiver does 100GbE use?
There is no single cable or optic implied by “100GbE.” IEEE’s Ethernet overview covers PHYs for coaxial cable, twisted-pair cable, fiber-optic cable, and electrical backplanes. The appropriate option depends on the PHY, link distance, endpoint ports, and installation.
#1 Best Overall
- 4 x 100GbE QSFP28 RJ45 and 8 x 25GbE SFP28 ports to offer a backbone switching capacity of 1200Gbps for uplinking server rooms.
- 600 Gbps Total Non-Blocking Throughput & 1200Gbps Switching Capacity
- Powered by QNAP’s QSS (QNAP Switch System) switch OS that comes with an easy-to-use Web GUI and value-added functions to simplify network set up and management.
- Supports Layer 2 management features, such as LACP, VLAN, ACL and LLDP, for network bandwidth management and security.
- Supports FEC (Forward Error Correction) and IEEE-802.3ap Auto-Negotiation for high compatibility to connect to QNAP 25GbE NAS or NAS installing 100G network cards for high-performance, low-latency computing.
100GBASE-SR4 over multimode fiber
IEEE 802.3bm added 100 Gb/s operation over multimode fiber, including 100GBASE-SR4. IEEE 802.3bm-2015 amendment record In the IEEE task-force baseline material, SR4 is identified for 100 m of multimode fiber; that figure describes this specific SR4 baseline context, not every multimode-fiber link or all 100GbE implementations. IEEE P802.3bm adopted baseline proposals
100GBASE-LR4 over single-mode fiber
As one vendor-documented example, Cisco specifies a QSFP 100GBASE-LR4 module for links up to 10 km over standard G.652 single-mode fiber, using duplex LC connectors. Cisco 100GBASE QSFP-100G modules data sheet This is a specification for that module example, not a universal reach guarantee for 100GbE.
Rank #2
- Ultra-fast 100G & 25G Connectivity – Delivers ultra-high-speed non-blocking throughput with 2 x 100GbE QSFP28, 4 x 25GbE SFP28, and 24 x 10GbE (RJ45) ports. Purpose-built for AI clustering workloads, large-scale NAS deployments, and high-bandwidth enterprise environments.
- Layer 3 Lite-Managed Features – Optimize your IT infrastructure with a robust web GUI supporting IPv4/IPv6 static routing, VLAN, QoS, and bandwidth control. Enables efficient network segmentation and highly secure data routing.
- Top-Of-Rack (ToR) Data Center Design – Engineered for server rooms requiring low-latency connectivity. Perfect for intensive virtualization (VMware ESXi, Hyper-V), enterprise storage area networks (SAN), and high-res media production workflows.
- Lossless Network Performance – Built-in advanced technologies including Priority Flow Control (PFC) and Explicit Congestion Notification (ECN). Minimizes packet loss and bottlenecking, making it ideal for optimizing RoCEv2 and high-speed data transmission.
- Future-Proof Scalabilty – Seamlessly bridge modern 100G/25G fiber optical backbones with existing 10G copper setups. Provides flexible multi-gigabit integration, ensuring cost-effective migration and scalable upgrades for growing businesses.
How to choose a 100GbE link
Check the complete link rather than selecting hardware from the 100GbE label alone:
Do these 3 things before closing this tab:
1Clear out junk files and repair common Windows errors2Fix the driver behind crashes, sound loss and screen glitches3Repair Windows errors before they cause bigger problems- Identify the PHY supported by both the switch or network adapter and the proposed link.
- Confirm the module form factor is supported by the exact device port.
- Match the medium and fiber type to the selected PHY.
- Verify connector type and required reach against the equipment specifications.
- Confirm compatibility and interoperability for the devices at both ends before deployment.
IEEE standards define the relevant Ethernet speed and PHY framework; vendor documentation supplies the implementation details for individual products. Product specifications and availability can change, so use the documentation for the exact hardware being installed.
Quick Recap
Rank #3
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- Switch: Arista DCS-7260CX-64 64x QSFP100 Port Switch
- Model: DCS-7260CX-64
- Ports: 64x QSFP 100Gb Ports and 2x SFP+ Ports
- Airflow Fans: 4x Front Flow Fans
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