What Is Direct Attach Cable

A direct attach cable also known as DAC is usually a fixed assembly supporting high speed data that uses a small form-factor connector module as an optical transceiver on each end of a length of cable. With significant cost-saving and power-saving benefits, direct attach cable is now being widely used in data centers for short reach applications. It can be connected to switches, servers, routers, network work interface cards (NICs), Host Bus adapters (HBAs) providing high density and high data throughput.

Why Choose Direct Attach Cable

Direct attach cable with many significant benefits can satisfy the growing need for high speed data. The main benefits of direct attached cable are described in the following text.

 

Cost saving: the modules on the end of direct attach cable looks like optical transceivers. However, actually they very much different from optical transceiver. These small form-factor connector modules leave out the expensive optical lasers and some electronic components. That’s the main reason why the DAC is much cheaper than optical transceiver. Direct attach cable in some case can be an alternative to optical transceivers as it eliminates the separable interface between transceiver module and optical cable. Thus, choosing DAC in some cases can save a lot of money as well as time.

 

Low power consumption: to identify the modules on the end and cable type to the Ethernet interface, in both active direct attach cable and passive direct attach cable a small electrical component is used, which is low cost and consumes very little power compared with optical transceiver.

 

Supporting high data rate: DAC can provide high speed I/O (input and output) data. The most commonly used DAC can support high data rate of 10 Gb/s and 40 Gb/s. However, as technologies advanced, some vendor can provide direct attached cable supporting 120 Gb/s, like 120G CXP Cables.

 

Meet small form-factor standards: the modules on each end of DAC meet small form-factor standards which means DAC inherits some advantages of the small form-factor module, like space saving. Some time there is no need to upgrade the equipment by using a DAC.

 

Advance technologies like Big Data and Cloud which require high speed of data rate become more and more popular. To meet the ever growing need to high speed data transmission, many data centers are migrating from 10 GbE to 40 GbE or even 100 GbE. And some are considering about the migration, during which the cost is one of the most important factors to consider. Direct attach cable also known as DAC is a cost effective solution during the migration to 40GbE or 100GbE.

 

 

40GBASE QSFP+ Direct Attach Cable

 

With various benefits like abilities in data transmission and cost saving, direct attach cable is becoming increasingly popular for short distance top-of-rack (ToR) and middle-of row (MoR) data center deployments. It’s a cost-effective solution to 40G/100G migration. Currently direct attach cable are continuing to evolve to meet industry needs. Various types of directive attach cable are being provided. Fiberstore as a vendor of optical components provides DAC cable assemblies including 10G SFP+ Cables, 40G QSFP+ Cables, and 120G CXP Cables. For information please visit Fiberstore.