40G QSFP+ Direct Attach Copper Cabling Solutions

With the wide growth of network capacity and transmission speed in data centers, 40G QSFP+ direct attach copper cables are becoming more and more popular. Being compact, lightweight with low power, 40G QSFP+ direct attach copper cables are suited for 40G Ethernet, and other datacom and high-performance computing applications. Generally 40G QSFP+ direct attach copper cables can be divided into two types: 40G QSFP+ to 4 SFP+ direct attach breakout copper cables and 40G QSFP+ to QSFP+ direct attach copper cables. This post will firstly make an overview of 40G QSFP+ direct attach copper cables, then introduce two main types of 40G QSFP+ direct attach copper cables.

The 40G QSFP+ direct attach copper cables are designed for a short distance and high density cabling interconnect system capable of delivering an aggregate data bandwidth of 40Gb/s. They are suitable for in-rack connections between QSFP+ ports of switches. These cables consist of cable assemblies that connect directly into two QSFP+ modules, one at each end of the cable. They use integrated duplex serial data links for bidirectional communication and are designed for data rates up to 40 Gbps. 40G QSFP+ direct attach copper cables are cost effective solutions for interconnecting high speed 40G switches with existing 10G equipment or 40G switches.

The 40G QSFP+ to 4 SFP+ copper direct-attach breakout cables connect a 40G QSFP+ port of a switch on one end to four 10G SFP+ ports of a switch on the other end. By using these cables, one may deploy switches that have 40G Ethernet ports while the servers still have 10G Ethernet ports. These cables use high-performance, integrated duplex serial data links for bidirectional communication. They comply with QSFP+ mechanical, optical, and electrical specifications (SFF-8436), and the SFP+ electrical (SFF-8431) and mechanical interface (SFF-8432) standards. Currently, these breakout cables come in lengths of 1, 3, and 5 meters and active cables in lengths of 7 and 10 meters. They are suitable for very short distances and offer a very cost-effective way to connect within racks and across adjacent racks.

The 40G QSFP+ to QSFP+ direct attach copper cables, such as QFX-QSFP-DAC-3M or QFX-QSFP-DAC-1M, connect a 40G QSFP port of a switch on one end and to another 40G QSFP port of a switch on the other end. Supporting similar applications to SFP+, these four-lane high speed interconnects were designed for high density applications at 10Gb/s transmission speeds per lane. Usually the QSFP+ to QSFP+ direct attach copper cable links are equivalent to 4 SFP+ cable links, providing greater density and reduced system cost. There are passive and active QSFP+ to QSFP+ direct attach copper cables. Active QSFP+ to QSFP+ direct attach copper cable assembly is capable of distances of up to 10 meters. While passive QSFP+ to QSFP+ direct attach copper cable assembly is suitable for shorter distances for 40G links. Designed for short length and high speed interconnects, 40G QSFP+ to QSFP+ direct attach copper cables offer a cost-effective alternative to fiber optic cable assemblies. They are also intended for short distance applications such as point-to-point in-rack and across rack network switch/server connections.

With the increasing deployment of 40 Gigabit Ethernet system, many fiber optic vendors worldwide deal with direct attach copper cables because of their low cost, low power consumption and high performances. 40G QSFP+ direct attach copper cabling solutions, either 40G QSFP+ to 4 SFP+ or QSFP+ to QSFP+ direct attach copper cables, help improve the availability of data center networks and support mission-critical applications.