Data Centers | Informative

Comparing Data Center Network Designs: Top of Rack (ToR) vs. End of Row (EoR)

Designing an efficient data center network involves choosing the right architecture to balance scalability, manageability, and cost. Two common approaches—Top of Rack (ToR) and End of Row (EoR)—offer distinct advantages depending on your operational priorities.

Top of Rack (ToR) Architecture

Switch Placement

Network switches are installed at the top of each ITE rack, enabling direct connections to the servers within the same rack.

Independent Operation

Each rack acts as a standalone unit, simplifying maintenance and isolating issues.

Fiber Backbone

Fiber optic uplinks connect ToR switches to the core network, supporting higher bandwidth and reducing copper cable clutter.

End of Row (EoR) Architecture

Centralized Switching

Servers in each ITE rack connect directly to aggregation switches located at the end of each row—eliminating the need for in-rack switches.

Row-Based Management

The entire row operates as a network group; issues with the aggregation switch can impact all connected racks.

High Cabling Demand

Requires extensive copper cabling between each server and the row-end switch.

ToR vs. EoR At a Glance

FeatureTop of Rack (ToR)End of Row (EoR)
Switch Deployment1 switch per ITE rack1–2 switches per row
Rack ManagementRacks operate independentlyRacks operate as part of a group
Switch CountHigher number of switchesFewer switches needed
CablingShorter, fewer cables (in-rack)Longer, more cables across racks
Power & CoolingHigher consumption per rackLower overall consumption and better airflow

Top of Rack (ToR) architecture is ideal for data centers seeking greater modularity and localized fault isolation, allowing each rack to operate independently with minimal impact from failures. On the other hand, End of Row (EoR) design is better suited for environments where reducing switch costs and improving overall cable management are priorities. Both network designs offer distinct benefits, and the right choice depends on your data center’s scalability goals, operational requirements, and long-term infrastructure strategy.

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