Cisco 40GBase-CSR4 40Gbps Multi-Mode Fiber Transceiver Module

Overview

The Cisco QSFP-40G-CSR4 is a multimode fiber transceiver module designed to deliver 40 Gigabit Ethernet connectivity within data centers, campus cores, and high-performance computing clusters. It aggregates four 10 Gigabit channels into a single 40 Gbps link, enabling efficient traffic movement between switches, routers, servers, or storage arrays without the need to replace existing multimode cabling. Supporting distances up to 300 meters on OM3 fiber and 400 meters on OM4 fiber, it covers most rack-to-rack or room-to-room connections in modern facilities with ease.

Installation is straightforward: the transceiver slides into any Cisco device with a standard QSFP+ port and connects via an MPO or MTP cable. Its 12-fiber ribbon interface aligns with common trunk infrastructures, allowing bandwidth upgrades while maintaining organized cable management. The module’s low power consumption and compact design make it well suited for high-density network environments.

Key features

• Combines four 10 Gbps lanes into a single 40 Gbps link for high-throughput data transfer
• Supports up to 300 meters on OM3 and 400 meters on OM4 multimode fiber, covering typical data center distances
• MPO or MTP connector enables direct termination to 12-fiber ribbon cables, simplifying cabling infrastructure
• 4 x 10G breakout mode allows a single QSFP+ port to support four independent 10GBase-SR connections, ideal for aggregating server or storage links
• Compatible with any Cisco platform featuring a QSFP+ slot, ensuring broad device support
• Low power draw and compact size help maximize port density in dense network deployments

Key specs

• Data rate: 40 Gbps total bandwidth over four parallel 10 Gbps lanes
• Reach: up to 300 meters on OM3 laser-optimized multimode fiber
• Reach: up to 400 meters on OM4 laser-optimized multimode fiber
• Connector type: MPO or MTP for 12-fiber ribbon cables
• Form factor: QSFP+ transceiver module
• Compatibility: Cisco devices with QSFP+ ports
• Power consumption: low, optimized for high-density environments

Connectivity and compatibility

This transceiver integrates seamlessly with Cisco networking equipment that supports QSFP+ slots, providing a straightforward upgrade path for existing multimode fiber infrastructures. The MPO/MTP connector supports direct connection to standard 12-fiber ribbon cables, which are common in data center trunk cabling. The 4 x 10G breakout mode expands flexibility by enabling multiple 10GBase-SR links from a single port, which is useful for connecting multiple servers or storage devices to a top-of-rack switch.

Ideal uses and environments

The Cisco QSFP-40G-CSR4 fits well in data centers and enterprise networks where high bandwidth and efficient cabling are priorities. It is a strong choice for network engineers looking to upgrade bandwidth without overhauling existing multimode fiber cabling. Its support for breakout mode makes it suitable for aggregating multiple 10G connections in leaf-spine architectures or high-performance computing clusters. The module’s low power and compact design also make it practical for dense switch deployments where space and energy efficiency matter.