Cisco 40G QSFP+ Modules and Cabling Solutions Overview

Large network capacity growth in data centers boosts the evolution of cabling infrastructure to accommodate the continued requirements for scalability, management, flexibility, and reliability. Currently, the 10 Gigabit Ethernet (GbE) system can’t meet the bandwidth needs of enterprises very well. And it’s necessary to deploy 40GbE infrastructure to satisfy the fast-growing bandwidth needs with 40G products, such as 40G QSFP+ modules and 40G cables. Many fiber optic vendors worldwide deal with 40G QSFP+ modules and 40G cables, such as Cisco, Juniper, and Brocade. And this text mainly introduces Cisco 40G QSFP+ modules and 40G cables.

This text mainly introduces Cisco 40G QSFP+ modules and cabling solutions.

Cisco 40G QSFP+ Modules Overview

Cisco 40G modules offer customers high-density and low-power 40GbE connectivity options for data center, high-performance computing networks, enterprise core, and distribution layers applications.

  • Cisco QSFP-40G-SR4-S

Cisco 40GBASE-SR4 QSFP+ module is specified to run over laser-optimized OM3 and OM4 multimode fibers (MMFs) with link lengths of 100 and 150 meters, respectively. This module establishes high-bandwidth 40G optical links over 12-fiber parallel fiber terminated with MPO/MTP multi-fiber connectors. Cisco QSFP-40G-SR4-S is optimized to guarantee interoperability with any IEEE-compliant 40GBase-SR4 module.

  • Cisco QSFP-40G-LR4-S

Cisco 40GBASE-LR4 QSFP module is able to accomplish the maximum link lengths of 10 kilometers over a standard pair of G.652 single-mode fiber (SMF) with duplex LC connectors. The 40GbE signal is carried over four wavelengths. Multiplexing and demultiplexing of the four wavelengths are managed in the device. This QSFP-40G-LR4-S transceiver only supports 40GBase Ethernet rate and does not support FCoE.


Cisco 40G Cabling Solutions

Cisco 40G cabling options include Cisco QSFP to QSFP direct attach cables (DACs) and Cisco QSFP to 4 SFP+ breakout cables.

  • Cisco QSFP to QSFP DACs

Cisco QSFP to QSFP DAC solutions can be further divided into Cisco QSFP to QSFP copper DAC and QSFP to QSFP active optical cable (AOC). (AOC is a kind of DAC)

Cisco QSFP to QSFP direct attach copper cable assembly is designed for very short distances. It offers a very cost-effective way to establish a 40G link between QSFP ports of Cisco switches within racks and across adjacent racks. Cisco offers QSFP to QSFP copper DACs in both active copper and passive copper version.

  • Cisco QSFP to 4 SFP+ Breakout Cables

Similarly, Cisco QSFP to 4 SFP+ breakout cable solutions also fall on two options: Cisco QSFP to 4 SFP+ copper breakout cables and Cisco QSFP to 4 SFP+ active optical breakout cables.

Cisco QSFP to four SFP+ copper breakout cables connect to a 40G QSFP port of a Cisco switch on one end and to four 10G SFP+ ports of a Cisco switch on the other end. Cisco currently offers passive copper cables in lengths of 1, 3, and 5m. Like QSFP-4SFP10G-CU3M, Fiberstore compatible Cisco QSFP-4SFP10G-CU3M is the ideal 40G link solution when the link length is 3m.


In Cisco QSFP to four SFP+ active optical breakout cable assembly, AOC breakout cables are much thinner and lighter than copper breakout cables, enabling easier cabling infrastructure and efficient system airflow, free from EMI issues which is critical in high-density racks.


Cisco 40G QSFP+ modules and cables offer multiple connectivity options with media type (DAC, AOC, SMF, and MMF) in data centers. AS a professional fiber optical product manufacturer and supplier, as well as a third party, Fiberstore supplies a large number of 40G QSFP+ modules and cables which are 100% compatible with the original Cisco 40G products. You can visit Fiberstore for more information about 40G QSFP+ modules and cables which are fully compatible with Cisco.


Author: Angel

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