40G QSFP+ Direct Attach Copper Cables

With the wide deployment of 40 Gigabit Ethernet, the 40G QSFP+ direct attach copper cables are becoming more and more popular due to the compact size, low power and cost-effectiveness. 40G QSFP+ to QSFP+ direct attach copper cables and 40G QSFP+ to 4 x 10G SFP+ direct attach copper cables are hot pluggable and parallel passive / active copper cables for storage, data, and high-performance computing connectivity.

QSFP+ to QSFP+ Direct Attach Copper Cables

QSFP+ to QSFP+ direct attach copper cables are hot-removable and hot-insertable. A cable consists of a cable assembly that connects directly into two QSFP+ modules, one at each end of the cable. The cables use integrated duplex serial data links for bidirectional communication and are designed for data rates up to 40 Gbps. QSFP+ to QSFP+ direct attach copper cables are suitable for very short distances and offer a highly cost-effective way to establish a 40G link between QSFP+ ports of QSFP+ switches within racks and across adjacent racks. These cables connect to a 40G QSFP port of a switch on one end and to another 40G QSFP port of a switch on the other end.

QSFP+ to 4 SFP+ Direct Attach Copper Cables

The move from 10G to 40G Ethernet will be a gradual one. It is very likely that one may deploy switches that have 40G Ethernet ports while the servers still have 10G Ethernet ports. For that situation, we should use a QSFP+ to 4 SFP+ direct attach breakout copper cable. These cables connect to a 40G QSFP port of a switch on one end and to four 10G SFP+ ports of a switch on the other end, which allows a 40G Ethernet port to be used as four independent 10G ports thus providing increased density while permitting backward compatibility and a phased upgrade of equipment.

Directions for Use

The 40G QSFP+ direct attach copper cables are used to connect switch to switch or switch to server. When we use a fiber optic transceiver and patch cable to establish a fiber link, we should firstly plug the transceiver to the switch and then plug the patch cable to the transceiver. But for a QSFP+ direct attach copper cable, both SFP+ connector and QSFP+ connector can be directly inserted into the switch and don’t need a transceiver at all, which provides a really cost-effective solution for interconnecting high speed 40G switches to existing 10G equipment or 40G switches to 40G switches.

40G QSFP+ direct attach copper cables can provide inexpensive and reliable 40G speed connections using copper cables with distances reaching up to 30ft (~10 meters length). Cost of short reach connectivity is significantly reduced by avoiding the more costly fiber transceivers and optical cables. As the main fiber optical manufacturer in China, Fiberstore provides a good selection of 40G QSFP+ copper cables, both passive and active copper cables are available. For longer distances, active copper or optical cables are required. For more information or quotation, please contact us via sales@fs.com.

FAQ on Fiberstore 40G Cabling and Transceivers

With an increasing demand for more bandwidths, faster data rates and higher performance in telecommunication networks, the business case for 40 Gigabit Ethernet is becoming inescapably compelling. However, many users may feel confused when using 40G cables and optical transceivers. This article will solve the most frequently asked questions on Fiberstore’s 40G cabling and transceivers.

Q1: What 40G cables and transceivers are available from Fiberstore?

Fiberstore supplies a full range of both copper cables and optical transceivers for 40GbE, compliant to the IEEE standards. For copper both QSFP+ to QSFP+ (40G to 40G) and QSFP+ to SFP+ (40G to 4x10G) cables enable short reach options. For longer distances, Fiberstore offers a wide range of optical transceivers for various fiber types and reach requirements.

Q2: What does the IEEE 40GBASE-X standard describe?

The IEEE 40GBASE-X standard describes the following:

• 40GBASE-SR4 It reaches 40-Gbps Ethernet over four short-range multimode fiber optic cables and supports link lengths of 100m and 150m respectively on laser-optimized OM3 and OM4 multimode fiber cables. In this process, the multimode fiber uses parallel-optics transmission instead of serial transmission due to the 850nm vertical-cavity surface-emitting laser (VCSEL) modulation limits. For example, Mellanox MC2210411-SR4 compatible 40GBASE-SR4 QSFP+ transceiver from Fiberstore supports link length of 100m over multimode fiber cable.
• 40GBASE-LR4 It reaches 40-Gbps Ethernet over four wavelengths carried by a single long-distance singlemode fiber optic cable and supports link lengths of up to 10 km over single-mode fiber with duplex LC connectors. It operates at a wavelength of 1310 nm. The 40 Gigabit Ethernet signal is carried over four wavelengths with 10G on each wave.
• 40GBASE-CR4 It is a direct attach cable segment with the QSFP+ modules attached to each end of the cable. It reaches 40-Gbps Ethernet over four short-range twinaxial copper cables bundled as a single cable and supports link lengths of up to 10 km over a standard pair of G.652 single-mode fiber with duplex LC connectors.

Q3: Can the 40G-LR4 transceiver be split into 4x10G connections?

No, 40G-LR4 cannot be split into 4x10G. The 40GBASE-LR4 uses 4 lambdas (or wavelengths) on a pair of single mode fibers, and does not lend itself to “splitting” into 4 pairs without substantial complexity to split out the wavelengths. The unique characteristic of 40GBASE-SR4 is that it uses parallel (ribbon) fiber, which allows the creation of 4 fiber pairs. As an alternative single mode parallel 40G optics are available (40G-PLRL4 and 40G-PLR4) that do allow for splitting into 4x10G (single mode).

Q4: How does the QSFP+ to SFP+ fiber convertor allow 4x 10G?

The IEEE 40G-SR4 standard specified a parallel technology, with 4 lanes in each direction. The purpose of this was to allow for easier development of 40G, re-using 10G components. As a side result the 40G multi-mode transceivers can also support 4x10G modes. A fiber that connects from one 40G port to four 10G ports provides a physical path to allow the source “40G” port running in 4x10G mode to be connected to 4 unique 10G destinations. As the fiber is a passive medium it has no concept of the 40G or 10G signals.

Fiberstore provides various types of 40G cables and transceivers including single-mode and multi-mode with different channels and wavelengths. All these transceivers are compatible with famous brands, like Brocade QSFP+, HP QSFP+, Juniper QSFP+, etc. They can also be customized to meet your special requirements.