How to choose the Direct Attach Copper Cable correctly?

1.Choose the Right Connector
DAC cable terminated with SFP+ connectors is commonly used in 10GbE networks. However, there are many other connector options for DAC cables which meet the interconnection demands of higher speed networks. Thus, choosing the right connector according to your network requirement is very important. In general, you could choose the SFP+ for 10GbE, QSFP+ for 40GbE, SFP28 for 25GbE and QSFP28 for 100GbE. In addition, breakout DACs like QSFP+ to 4x SFP+ DAC is an ideal choice for 10G to 40G migration.
2. AWG Is Also an Important Factor
AWG is another important factor of DAC cables. General specifications like 24AWG, 28AWG and 30AWG are available in the market. Always remember a rule when choosing the AWG—the longer the distance, the higher the AWG rating should be.
3. Choose the Enough Length
The maximum cable length differs from passive and active DAC cables. Generally, passive cable supports 5 meters or shorter lengths. Whereas active cable can support more than 5 meters (up to 15 meters). Thus, when the distance between connection points is less than 5 meters, passive DAC cable is recommended to use but ensure that your switch can support the passive cable (refer to the first guide). When the distance exceeds 5 meters, it is highly recommended to use active DAC cables to ensure the signal is transferred all the way through. The cost may be a bit higher, but the signal is improved and gives peace of mind by creating a trustworthy connection.
Direct attach copper cables are a low-cost alternative to traditional fiber and twisted-pair copper cabling in top-of-rack and middle-of-row. When buying a DACs, parameters such as passive or active, cable connector, AWG, length and so on should be properly selected. This post is a simple buying guide for reference. If you want to purchase high-quality and cost-effective DAC cables, it is highly recommended to visit http://www.fiber-mart.com or contact sales@fiber-mart.com for more details.

What is SFP+ Direct Attach Copper Cable(DAC)?

In today’s market, Direct Attach Cables (DAC)provide an excellent pre-terminated and factory assembled & tested solution for both copper and fiber optic cabling in data centers.

 

In today’s market, Direct Attach Cables (DAC)provide an excellent pre-terminated and factory assembled & tested solution for both copper and fiber optic cabling in data centers. It is a kind of optical transceiver assembly widely applied in storage area network, data center, and high-performance computing connectivity etc. The DAC cables are used to connect one mobility access switch with another when forming a stack.

 

Direct-Attach Cables (DAC) are cost efficient close-range interconnection media widely used in telecom operator equipment rooms, data centers and corporate networks for connecting LAN and SAN equipment in same or neighboring racks. Our multi-vendor compatible Direct-Attach Cables portfolio support full range of transmission speeds from 10 Gbps up to 100 Gbps applications, customizable length of cables and current most popular interface assembly form factors – QSFP and SFP. Our multi-vendor compatible Direct-Attach Cables portfolio is compatible with 80% of networking equipment, where is not implemented a special algorithm for protection against third party modules. However – we can provide Direct-Attach Cables with custom-encoded firmware in order to make it work almost in any equipment and we can support encoding of each end to support different vendor equipment, allowing using Direct-Attach Cables as cross-platform interconnection medium.

 

SFP+ direct attach cable (DAC) is a fixed assembly that is purchased at a given length, with the SFP+ connector modules permanently attached to each end of the cable. SFP+ DAC provides high performance in 10 Gigabit Ethernet network applications, using an enhanced SFP+ connector to send 10 Gbps data through one paired transmitters and receivers over a thin twinax cable or fiber optic cable. The 10G SFP+ Cable is designed to use the same port as an optical transceiver, but compared with optical transceivers, the connector modules attached to the cable leave out the expensive optical lasers and other electronic components, thus achieving significant cost savings and power savings in short reach applications.

 

SFP+ DAC is a low cost alternative to traditional fiber and twisted-pair copper cabling in data center deployments. SFP+ DAC provides better cable management for high-density deployments and enhanced electrical characteristics for the most reliable signal transmission

DDAC

Passive and Active 10G SFP+ Direct Attach Cable (DAC)

SFP+ Direct Attach is known as the successor technology to 10GBASE-CX4. SFP+ Direct Attach, as implied in the name, uses SFP+ MSA and by using the inexpensive copper twinaxial cable with SFP+ connectors on both sides, provides 10 Gigabit Ethernet connectivity between devices with SFP+ interfaces. SFP+ Direct Attach has a 10 meter distance limitation, thus the target application is interconnection of top-of-rack switches with application servers and storage devices in a rack.

Passive cables are much less expensive but require the host to do the work of driving it properly.

Benefits:

  • Lower Costs
  • Higher Reliability
  • Lower Power Consumption
  • Plug and Play Simplicity

Fewer Components (No Active Tx /Rx Components)

Only Capacitors, Resistors, EEPROM, Cable

 

Tradeoffs:

  • Reduced Cable Flexibility
  • Reduced Modularity
  • Limited Distance
  • No LOS
  • No TX Disable
  • No Interrupts
  • Limited Management Interface
  • Host must drive Cu cable

 

Active cables offer the benefit of optical-module.

Benefits:

  • Enhanced Signal Integrity
  • Longer Cable Lengths
  • Transmit Pre-emphasis
  • Active/Adaptive Receive Equalization
  • Tx Disable
  • Loss of Signal (LOS)
  • Interrupts
  • Management Interface

 

Tradeoffs:

  • Higher price

 

Fiber-Mart supplies various kinds of high speed interconnect DAC cable assemblies. All of our direct attach cables can meet the ever growing need to cost-effectively deliver more bandwidth, and can be customized to meet different requirements. For more information, pls visit www.fibermart.com. pls not hesitate to contact us for any question:service@fiber-mart.com

 

 

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