Cisco QSFP-40G-SR4 Compatible 40GBASE-SR4 QSFP+ 850nm 150m DOM MTP/MPO-12 MMF Optical Transceiver Module

Overview

This module is a high-performance, parallel optical QSFP+ transceiver, engineered as a fully compatible alternative to the Cisco QSFP-40G-SR4. It is designed for short-reach 40 Gigabit Ethernet applications, offering robust connectivity up to 150 meters over OM4 multi-mode fiber (MMF). The module is a staple in data centers and enterprise campus networks for switch-to-switch and switch-to-server connections.

The transceiver is compliant with the 40GBASE-SR4 standard and features four independent 10Gbps transmit and receive channels, resulting in an aggregate bandwidth of 40Gbps. This parallel architecture, which uses an MPO-12 connector, enables two distinct operational modes: a native 40G link or a 4x10G breakout configuration. The breakout capability allows a single 40G QSFP+ port to connect to four separate 10G SFP+ ports, providing exceptional density and flexibility for network architects.

Key Features

• 100% compatible with Cisco platforms that support the QSFP-40G-SR4 module.
• Standard: Compliant with IEEE 802.3ba 40GBASE-SR4 and QSFP+ MSA.
• Dual Functionality: Supports native 40G and 4x10G breakout modes.
• Data Rate: 41.2 Gbps aggregate (4 x 10.3 Gbps).
• Reach: Supports up to 100m on OM3 MMF and 150m on OM4 MMF.
• Wavelength: 850nm VCSEL array.
• Connector: MPO-12/MTP-12.
• Built-in Digital Optical Monitoring (DOM/DDM) for real-time diagnostics.
• Hot-pluggable QSFP+ form factor.

Applications

The QSFP-40G-SR4 compatible module is an excellent choice for:

• High-density 40G data center and enterprise network links.
• Switch-to-switch or switch-to-server interconnects.
• 40G to 4x10G fan-out for top-of-rack aggregation from servers.
• High-performance computing (HPC) and storage area networks (SAN).

Specifications

Cross-Platform Compatibility

Programmed for seamless integration with Cisco equipment, this module’s adherence to MSA standards ensures it can also be deployed in networking hardware from other major manufacturers that support 40GBASE-SR4 QSFP+ optics.

FAQ (Technical & Product Questions)

1. How does the 4x10G breakout mode work with the QSFP-40G-SR4?

Breakout mode is enabled using an MPO-to-4xLC fan-out cable. This cable connects to the MPO-12 port on the QSFP-40G-SR4 module and splits the four 10G lanes into four separate duplex LC connectors. These LC connectors can then be plugged into four individual 10GBASE-SR SFP+ transceivers on other devices like servers or access switches.

2. What is the difference between QSFP-40G-SR4 and QSFP-40G-SR-BD?

They are different technologies. The QSFP-40G-SR4 uses four parallel fiber pairs (8 fibers total) within an MPO cable for short-reach links. The QSFP-40G-SR-BD (Bi-Directional) uses just one pair of multi-mode fibers (2 fibers total) with a duplex LC connector, transmitting and receiving different wavelengths on each fiber. They are not interoperable.

3. What fiber optic cable is required for a native 40G link?

For a direct 40G connection between two QSFP-40G-SR4 modules, you must use a Type B MPO-12/MTP-12 female-to-female patch cable. To achieve the maximum 150m distance, OM4 multi-mode fiber is required. OM3 fiber can be used for distances up to 100m.

4. Can I use this QSFP+ module in a 100G QSFP28 port?

Yes, in most cases. QSFP28 ports are generally backward compatible with QSFP+ modules. When a QSFP-40G-SR4 is plugged into a QSFP28 port, the port will operate at 40G. However, you should always check your switch’s documentation to confirm compatibility.

5. Is this module compatible with the Cisco QSFP-40G-SR4-S?

Yes. The QSFP-40G-SR4 and QSFP-40G-SR4-S are functionally identical and fully interoperable. The “-S” suffix on the Cisco part number indicates it is an S-Class optic, optimized for standard enterprise and data center temperature ranges, which this module also meets.