EoR (End-of-Row) Switch

➡️ What Is an EoR (End-of-Row) Switch?

An EoR (End-of-Row) switch is a network switch placed at the end of a data-center rack row, aggregating connections from multiple server racks into a centralized switching point. All servers in the row connect to the EoR switch using structured horizontal cabling, typically copper (Cat6A) or fiber.

This architecture reduces the number of switches required and centralizes management, making it a popular design for large-scale data centers, enterprise facilities, and environments emphasizing cable organization and simplified operations.

➡️ How the End-of-Row Architecture Works

The End-of-Row architecture follows a centralized aggregation design:

  1. Each server rack uses patch panels for horizontal cabling.

  2. Cables from individual racks run to the row’s end.

  3. A set of high-density EoR switches aggregates all server links.

  4. The EoR switches uplink to core or spine switches using higher-speed optical interfaces such as 40G, 100G, or 400G.

Key Characteristics of EoR Architecture

  • Centralized switch placement → fewer switches, easier control

  • High-density aggregation ports → commonly 10G, 25G, 40G, 100G

  • Structured cabling → improves airflow and cable management

  • Consistency across racks → easy for standardized deployments

End-of-Row Architecture

➡️ Advantages of EoR (End-of-Row) Switching

▷ Operational Benefits

  • Simplified management: All switches for the row are in one location, reducing time for maintenance and configuration.

  • Lower switch count: Unlike ToR (Top-of-Rack), which places a switch on every rack, EoR consolidates the number of devices.

  • Better organization: Less clutter inside each rack and cleaner cable routing.

  • Reduced power consumption per rack: No need to install a switch in every cabinet.

▷ Cost Benefits

  • Lower CAPEX: Fewer ToR switches to purchase and maintain.

  • Reduced spare parts inventory: Single model per row, easy hardware standardization.

➡️ Disadvantages of EoR Switching

Technical Limitations

  • Longer horizontal cabling: Cable costs increase compared to ToR.

  • Less flexibility: Adding new servers requires extended cable runs.

  • Potential congestion: High server density demands high-capacity EoR switches.

Environmental Considerations

  • Requires more structured cabling trays and pathways.

  • Cable bulk may limit future scalability without proper planning.

➡️ EoR vs ToR: What’s the Difference?

1. ToR (Top-of-Rack) Overview

  • Switch is installed inside each rack.

  • Short server-to-switch cables (≤3m DAC).

  • More switches required across the data center.

2. Major Differences

Feature

EoR (End-of-Row)

ToR (Top-of-Rack)

Switch location

End of each row

Inside each rack

Number of switches

Fewer

Many

Cabling length

Longer

Very short

Cable cost

Higher

Lower

Scalability

Moderate

Very high

Management

Centralized

Distributed

Best for

Large structured cabling environments

High-density modern data centers

3. Summary

  • EoR = fewer switches, more cabling

  • ToR = more switches, less cabling, faster scaling

➡️ When Does EoR Architecture Make Sense?

EoR is ideal for environments that need:

  • Centralized switch management

  • Long-term structured cabling

  • Fewer network devices to maintain

  • Lower per-rack power consumption

Typical Deployment Scenarios

  • Medium to large enterprise data centers

  • Government, finance, and manufacturing facilities

  • Co-location data centers with predictable rack layouts

  • Data halls using high-density horizontal cabling systems

➡️ How to Deploy an EoR Switch Architecture

♦ Step-by-Step Deployment Framework

1. Define bandwidth requirements

  • Server access speed: 1G / 10G / 25G

  • Uplink aggregation: 40G / 100G / 400G

2. Select high-density EoR switches

Focus on:

  • 48×10G/25G ports

  • 6–8×40G/100G uplinks

  • Support for MLAG/VPC, BGP, VXLAN, EVPN

3. Plan structured cabling

  • Fiber for long runs

  • Cat6A for ≤100m

  • Use horizontal pathways and trunk cabling

4. Choose compatible optical transceivers and DAC/AOC cables

(Recommended below)

5. Implement redundancy

  • Dual EoR switch pairs

  • Active-active uplinks

6. Test latency, throughput, and failover

♦ Recommended Optical Transceivers and Cables for EoR

LINK-PP provides cost-effective and fully compatible optical transceivers for mainstream vendors.

Optical Transceivers

1. Recommended 10G Modules for EoR Access Layer

2. Recommended 25G Modules

3. Recommended Uplink Modules (40G / 100G)

H3. Recommended Cables

DAC (Direct Attach Cable)
DAC (Direct Attach Cable)

  • Best for ToR/EoR short runs (≤5m)

AOC (Active Optical Cable)

  • Ideal for 5–30m aggregation or uplinks

All products are OEM-compatible, tested, and suitable for Cisco / HPE / Juniper / Dell / Arista.

➡️ Conclusion

EoR (End-of-Row) switching remains a powerful and cost-effective architecture for organizations seeking simplified operations, reduced switch count, and centralized management. While ToR is more flexible, EoR offers significant advantages in medium-to-large data centers with well-planned structured cabling.

When implementing EoR, selecting the right optical transceivers, DAC/AOC cables, and aggregation uplinks is essential for achieving performance, reliability, and scalability—areas where LINK-PP provides high-quality, cost-effective solutions.