QDD-400G-XDR4 Arista 400GBASE-XDR4 QSFP-DD Transceiver Up to 2km

Arista QDD-400G-XDR4 QSFP-DD Optical Module

The Arista QDD-400G-XDR4 is a high-performance 400GBASE-XDR4 transceiver engineered for data centers and enterprise networks. Designed for parallel single-mode fiber (SMF) connectivity, it supports transmission distances up to 2 km, ensuring reliable and scalable bandwidth expansion.

General Details

• Brand: Arista Networks
• Model Number: QDD-400G-XDR4
• Category: Optical Transceiver
• Form Factor: QSFP-DD

Technical Specifications

Optical Features

• Nominal Wavelength: 1310 nm
• Connector Interface: MTP/MPO-12 (APC)
• Transmission Reach: Up to 2 km over parallel SMF

Performance Metrics

• Aggregate Data Rate: 425 Gbps
• Power Usage: Typically 10.5W to 12W
• Transmitter: 4x EML (Electro-absorption Modulated Laser)
• Receiver: PIN photodiode

Monitoring & Diagnostics

• Digital Optical Monitoring (DOM/DDM): Real-time diagnostics supported
• Error Correction: Host FEC required for full 2 km operation

Environmental Conditions

• Operating Temperature: 0°C to 70°C (commercial range)

Arista QDD-400G-XDR4 Transceiver 2km Single-Mode Fiber

The Arista QDD-400G-XDR4 400GBASE-XDR4 QSFP-DD Transceiver is engineered to deliver ultra-high-speed optical connectivity for modern data center interconnects and high-performance enterprise core networks. Designed to support 400 Gigabit Ethernet transmission over parallel single-mode fiber (SMF) for distances up to 2 kilometers, this advanced QSFP-DD optical module addresses the growing demand for bandwidth scalability, low latency communication, and seamless interoperability within spine-leaf architectures and hyperscale computing environments.

Built for next-generation switching platforms, the Arista QDD-400G-XDR4 transceiver integrates cutting-edge optical components and digital signal processing technologies to ensure reliable long-reach performance. It supports the 400GBASE-XDR4 standard and utilizes parallel optical lanes over single-mode fiber, making it an optimal solution for structured data center cabling infrastructures that require predictable performance, reduced power consumption, and simplified fiber management.

400GBASE-XDR4 Technology and Standards Compliance

The 400GBASE-XDR4 specification defines a high-speed Ethernet interface designed to transport 400 Gigabits per second across multiple optical lanes. The Arista QDD-400G-XDR4 module operates using parallel optics, distributing the total 400G throughput across four optical lanes in each direction. This architecture enhances signal integrity and allows for longer transmission distances compared to short-reach multimode solutions.

IEEE and Industry Alignment

The module aligns with relevant IEEE 802.3 standards for 400G Ethernet, ensuring compatibility with industry-compliant networking equipment. It supports QSFP-DD Multi-Source Agreement (MSA) mechanical and electrical specifications, guaranteeing interoperability with QSFP-DD ports across various high-capacity switching and routing platforms. This compliance ensures seamless integration within existing infrastructure without requiring proprietary hardware adjustments.

Parallel SMF Transmission Architecture

Unlike duplex LC-based long-reach modules, the XDR4 design uses parallel single-mode fibers to transmit and receive multiple high-speed optical lanes simultaneously. This configuration supports improved signal performance and extended reach up to 2 kilometers. The architecture is particularly advantageous in spine-to-leaf aggregation layers and inter-switch connections across large data halls.

QSFP-DD Form Factor Advantages

The QSFP-DD form factor, or Quad Small Form-factor Pluggable Double Density, significantly increases port density while maintaining backward compatibility with QSFP-based systems. The Arista QDD-400G-XDR4 leverages this compact design to maximize switch faceplate density without sacrificing thermal performance or electrical reliability.

High Port Density in Data Centers

QSFP-DD allows networking equipment manufacturers to deploy up to 36 or more 400G ports on a single 1U switch. This high-density capability dramatically increases aggregate bandwidth per rack unit, enabling hyperscale data centers to scale efficiently without expanding physical footprint. The Arista 400G XDR4 transceiver contributes to these dense deployments by offering stable performance within tightly packed hardware configurations.

Electrical Interface and Signal Integrity

The QSFP-DD interface provides eight high-speed electrical lanes, each capable of supporting advanced modulation schemes and high data rates. Integrated digital signal processors inside the Arista QDD-400G-XDR4 module manage equalization, forward error correction compatibility, and real-time signal optimization, ensuring consistent throughput across demanding network loads.

Extended Reach up to 2 Kilometers

One of the key differentiators of the Arista QDD-400G-XDR4 transceiver is its ability to transmit data up to 2km over parallel single-mode fiber. This extended reach bridges the gap between short-range intra-rack connectivity and long-haul metro optical solutions, offering an ideal middle-ground for campus-scale data centers and distributed enterprise environments.

Ideal for Spine-Leaf Architectures

In modern spine-leaf topologies, switches must communicate with low latency and high bandwidth across multiple racks and rows. The 2km reach capability ensures reliable connections between aggregation switches, core routers, and distribution layers without the need for additional amplification or intermediate equipment. This simplifies network design and reduces total cost of ownership.

Data Center Interconnect Applications

The Arista QDD-400G-XDR4 module is well suited for data center interconnect scenarios where facilities are separated by moderate distances within the same campus. It enables high-capacity east-west traffic flows between compute clusters, storage arrays, and cloud infrastructure components while maintaining consistent performance and signal stability.

Optical Performance and Reliability

Engineered for mission-critical environments, the Arista QDD-400G-XDR4 400GBASE-XDR4 QSFP-DD Transceiver integrates advanced optical components designed to minimize signal degradation and maximize uptime. High-quality laser sources and photodetectors work in conjunction with precision optics to deliver reliable long-range performance over single-mode fiber cabling.

Low Power Consumption

Despite its high throughput capacity, the module is optimized for power efficiency. Reduced power consumption translates to lower cooling requirements within high-density switches, improving overall energy efficiency across large-scale deployments. This efficiency is essential for hyperscale operators seeking to reduce operational expenses and environmental impact.

Compatibility with Arista Networking Platforms

The Arista QDD-400G-XDR4 is specifically validated for use with Arista high-performance switching platforms that support QSFP-DD interfaces. When deployed within Arista’s data center switches, the module benefits from optimized firmware integration, ensuring consistent behavior, rapid link initialization, and stable throughput under heavy traffic conditions.

Seamless Integration with Arista EOS

When combined with Arista’s Extensible Operating System (EOS), the transceiver becomes part of an intelligent network ecosystem capable of automated provisioning, real-time analytics, and simplified management. EOS enables administrators to configure and monitor optical modules using unified command structures, streamlining deployment across large environments.

Interoperability in Multi-Vendor Environments

While optimized for Arista equipment, the QDD-400G-XDR4 adheres to industry MSA standards that facilitate interoperability with compatible third-party devices. This flexibility allows organizations to maintain vendor diversity while ensuring that 400G connectivity remains consistent and standards-based.

Structured Cabling and Fiber Infrastructure Considerations

Parallel single-mode fiber connectivity requires careful planning within structured cabling systems. The Arista 400G XDR4 transceiver supports high-fiber-count MPO or similar multi-fiber connectors designed to carry multiple optical lanes simultaneously. Proper fiber polarity management and cable quality are critical to achieving the full 2km reach specification.

Single-Mode Fiber Advantages

Single-mode fiber offers lower attenuation and higher bandwidth over distance compared to multimode fiber. By utilizing SMF, the Arista QDD-400G-XDR4 ensures long-term scalability as network speeds continue to increase. The same fiber plant can support future upgrades to higher-speed optical modules, protecting infrastructure investment.

Optimizing Cable Pathways

Network architects deploying 400G parallel optics must consider cable routing, patch panel design, and fiber management systems. High-density fiber trays and structured labeling practices enhance maintainability and minimize downtime during expansion or troubleshooting activities.

Performance in Cloud and Hyperscale Data Centers

Cloud service providers and hyperscale operators require networking components capable of sustaining extreme traffic volumes while maintaining minimal latency. The Arista QDD-400G-XDR4 transceiver supports these environments by delivering consistent 400G throughput across mission-critical workloads, including virtualization, distributed storage, artificial intelligence training clusters, and high-frequency data analytics.

Scalability for Rapid Growth

As data center capacity expands, 400G optical modules enable seamless bandwidth upgrades without fundamental architectural changes. The ability to deploy multiple QSFP-DD ports per switch supports incremental scaling, allowing operators to increase aggregate throughput while preserving existing rack layouts and power budgets.

High Availability and Redundancy

Redundant link configurations utilizing multiple 400G transceivers enhance network resilience. In high-availability clusters, traffic can be load-balanced across parallel links to prevent bottlenecks and ensure uninterrupted service in case of component failure.

Future-Proof Networking with 400G Technology

The evolution toward 400G Ethernet marks a critical milestone in enterprise and service provider networking. The Arista QDD-400G-XDR4 transceiver embodies this advancement by providing reliable, extended-reach connectivity suited for next-generation architectures. Its design aligns with the broader industry transition toward higher data rates, enabling organizations to prepare for increasing application demands and digital transformation initiatives.

Bandwidth-Intensive Applications

Emerging technologies such as real-time analytics, large-scale virtualization, container orchestration platforms, and AI-driven workloads generate unprecedented east-west traffic within data centers. The 400GBASE-XDR4 interface ensures that network infrastructure does not become a performance bottleneck, maintaining smooth communication between compute and storage resources.

Investment Protection Through Standards Compliance

Adherence to established Ethernet standards and QSFP-DD MSA guidelines ensures long-term compatibility and infrastructure protection. Organizations can deploy the Arista QDD-400G-XDR4 with confidence, knowing that it aligns with evolving industry roadmaps and future hardware generations.

Thermal Management and Operational Stability

High-speed optical modules generate significant heat due to advanced signal processing and laser operation. The Arista QDD-400G-XDR4 is engineered with optimized thermal characteristics to operate reliably within the environmental specifications of modern switching platforms. Efficient heat dissipation ensures stable performance even in high-density rack deployments.

Robust Construction and Quality Assurance

Manufactured to stringent quality standards, the transceiver undergoes comprehensive testing to validate optical output, signal integrity, and environmental tolerance. These rigorous validation processes contribute to long-term reliability in demanding enterprise and hyperscale environments.

Operational Temperature Range

The module is designed to function within specified operating temperature ranges typical of controlled data center facilities. Combined with real-time diagnostics monitoring, administrators gain full visibility into environmental conditions affecting optical performance.