Spine-Leaf Architecture: Data Center Transceivers

The data center challenge

EON Technology supplies multivendor transceivers for spine-leaf data center fabrics: 10G/25G at the top of rack and 100G/400G between leaf and spine, with compatibility validated by model, firmware, port and optical part number. You keep the fabric design you already have and source the optics from a single, platform-agnostic partner.

East-west traffic from modern workloads (virtualization, containers, AI training and inference) demands a network that is flat, predictable and low-latency. That is why data centers moved from the classic three-tier hierarchy to spine-leaf architecture (a folded Clos network), where every leaf connects to every spine and the hop count between any two servers stays constant.

That architecture only delivers if the optics keep pace: each layer has its own speed, form factor and fiber type, and a mismatch at any point shows up as a link that will not come up or a port running below its rated speed.

Typical architecture and where the optics fit

Server to leaf (ToR): 10G/25G with SFP+ or SFP28, or copper DAC inside the rack for short runs.
Leaf to spine: 100G with QSFP28 or 400G with QSFP-DD/OSFP. Multimode SR4 over MPO for in-room distances; single-mode LR4/CWDM4 over duplex LC for longer runs between rows or halls.
Data center interconnect (DCI): DWDM transport to carry many channels per fiber pair between sites.

Breakout (one 100G port into 4x25G, or 400G into 4x100G) raises port density and lets you reuse existing platforms while the next layer migrates. Each breakout leg still has to match the fiber (MPO for parallel optics) and the port configuration on the platform.

Recommended transceivers

QSFP28 modules (100G) for 100G spine-leaf links: 100G SR4 over MPO and 100G LR4/CWDM4 duplex.
SFP+ modules (10G) and SFP28 modules (25G) for ToR server access.
For 400G and hyperscale environments, see high-speed solutions.

Why EON Technology

We supply multivendor optics with compatibility validated by model, firmware, port and optical part number for Cisco, Arista, Juniper, HPE Aruba, Dell, Huawei and other data center platforms. Some platforms report third-party optics as unsupported; in that case transceiver recoding adapts and validates the module for your ToR or spine platform, with 90-day service coverage. You get significant savings against the OEM module and engineering support before and after purchase, backed by a 1- to 5-year product warranty. EON serves Latin America and Spain from a centralized operation in Colombia. Validate your fabric in a proof of concept, check the compatibility matrix or talk to an engineer.

Frequently asked questions

What transceivers are used in a spine-leaf architecture?

Leaf-to-spine links usually run at 100G (QSFP28) or 400G (QSFP-DD/OSFP), and servers connect to the leaf (ToR) at 10G/25G with SFP+/SFP28. Multimode uses SR4 with an MPO connector; single-mode uses LR4/CWDM4 with duplex LC.

What is the difference between ToR and EoR?

ToR (Top-of-Rack) places the access platform in each rack, shortening the copper/DAC run to the server. EoR (End-of-Row) centralizes the access layer at the end of the row. Both connect to the spine layer through 100G/400G optical links.

Do EON modules work on Cisco, Arista or Juniper data center platforms?

Compatibility is validated by model, firmware, port and optical part number on the main platforms. Some platforms report third-party optics as unsupported; in that case we offer transceiver recoding, which adapts and validates the module, with 90-day service coverage.