With the rapid development of networks, data centers have been facing the challenges of high bandwidth, high reliability and low latency, and are in urgent need of cost effective high-speed interconnection solutions. In short distance transmission, DAC high-speed cable has the advantages of low power consumption, low cost and ease of use compared to the combination solution of optical module + fiber patch cable, which is widely used in interconnected data centers.

Advantages of DAC high-speed cables compared to optical modules

²  Energy saving and environmental protection: The internal material of DAC high-speed cable is made of copper core, and copper has good heat dissipation effect, which is more energy saving and environmental protection.

²  Low power consumption: DAC high-speed cable has low power consumption, generally speaking, the power consumption of optical modules is more than 1W, but the power consumption of DAC high-speed cable is generally less than 0.5W.

²  Low cost: DAC high-speed cable optical devices without optical lasers and other electronic components, can effectively save manufacturing costs, and copper cable is much lower than the price of optical fiber, in the wiring DAC high-speed cable can effectively save the use of optical fiber, so as to achieve the effect of low cost. For example, two transmission distance of 1 meter 100G Cisco switch interconnection, if the DAC high-speed cable, only a 1-meter 100G DAC high-speed cable; if the optical module + fiber patch cable, two 100G SR4 optical modules and a 1-meter 12-core MTP fiber patch cable, the total price is 8 to 10 times more.

Detailed explanation of the DAC high-speed cable from the structure

DAC high-speed cable is composed of a cable and two optical devices.

Its cable uses silver-plated conductors, physical foam polyolefin material insulation core and pair shielding / total shielding, uniform distribution, with high mechanical strength and insulation adhesion, as well as excellent attenuation performance, low latency and anti-interference. The cable composition structure is divided into four main layers.

²  The first layer, the wrapped core, is mainly made by wrapping machine to combine two insulated cores and ground wires together, with a layer of aluminum foil and a layer of self-adhesive polyester tape wrapped outside.

²  The second layer, the cable-forming core, is mainly composed of multiple wrapped cores, again with a layer of polyester tape and aluminum foil mylar tape wrapped around the outer layer.

²  The third layer, the metal shielding mesh, is the wire braid outside the cable core, which is used to enhance the shielding effect of the wire and obtain better performance.

²  The fourth layer, the outer sheath, is made of polyethylene and other materials.

DAC high-speed cable ends of the optical device seems to be the same as the general optical module, but in fact, it is not a real optical module, because it does not have an optical laser and does not have electronic components, can only transmit electrical signals, cannot transmit optical signals. Because of this, DAC high-speed cable is cheaper than optical modules, which can greatly save costs and power consumption in short-distance applications, making it a low-cost, cost-effective communication solution.

In addition, DAC high-speed cable is divided into active DAC high-speed cable and passive DAC high-speed cable, the difference between the two is that the active DAC high-speed cable has an additional driver chip, while the active optical cable does not require a power supply skills to display its characteristics, while the active optical cable requires an external power supply to display the characteristics. In general, when the transmission distance is more than 5 meters, in order to reduce the problem of signal interference, choose active DAC high-speed cable is the most appropriate.

DAC High Speed Cables in Data Center Applications

DAC high-speed cable can be divided into 10G SFP+ DAC high-speed cable, 25G SFP28 DAC high-speed cable, 40G QSFP+ DAC high-speed cable and 100G QSFP28 DAC high-speed cable according to the different transmission rates, mainly used for data centers in the short distance direct connection. At the same time, DAC high-speed cable in order to meet the needs of user network upgrades, 40G QSFP+ DAC high-speed cable and 100G QSFP28 DAC high-speed cable with branch cable package form, can be used for 40G-4 * 10G, 100G-4 * 25G network upgrade application scenarios.

10G SFP+ DAC High Speed Cable

10G SFP+ DAC high-speed cables are widely used for interconnection between 10G fiber NICs, interconnection between 10G ToR switches and servers, stacking of 10G Ethernet switches, etc.

10G SFP+ DAC high-speed cable is based on pluggable small package optical transceiver module multi-source protocol, using copper shaft cable with SFP+ connectors at both ends, which can provide 10 Gigabit Ethernet connection between devices (such as servers, fiber NICs, switches, etc.) and SFP+ interfaces. In the past, RJ45 ports or SFP ports were used on server motherboards, but nowadays, with the development of big data as well as high bandwidth, 10G has started to be popular on servers.

25G SFP28 DAC High Speed Cable

25G SFP28 DAC high-speed cables are widely used for interconnecting 25G devices (such as servers, 25G fiber NICs, etc.) and supercomputers in a variety of scenarios.

25G SFP28 DAC high-speed cable follows IEEE P802.3by Ethernet standard, which can provide users with 25G high-bandwidth data interconnection capability. Due to the late introduction of 25G Ethernet, the application of its related optical communication products has not been popularized, however, with the arrival of 5G networks, the demand for 25G in 5G forward transmission will see a significant increase.

40G QSFP+ DAC High Speed Cable

40G QSFP+ DAC high-speed cable as a direct connection cable between 40G switches, with compact and independent 4-channel pluggable interface, backward compatible, suitable for stacking and cascading between 40G devices; at the same time, in order to meet the user‘s more connection needs, 40G QSFP+ to 4*SFP+ DAC high-speed cable and 40G QSFP+ to 4*XFP DAC high-speed cable came into being, to realize the network upgrade between 10G to 40G devices.

With the server port rate upgraded from 1Gbps to 10Gbps, the uplink from the access layer to the core layer is upgraded to 40Gbps/100Gbps in order to achieve the basis of non-blocking full line rate of the network, as the cost of 40G fiber link is cheaper compared to 100G, so most of the medium-sized enterprises will choose 40G when building data centers.

100G QSFP28 DAC high-speed cable

The 100G QSFP28 DAC high-speed cable has two interface types: QSFP28 to QSFP28 and QSFP28 to 4*SFP28. The 100G QSFP28 to 4*QSFP28 DAC high-speed cable is suitable for short distance stacking, cascading and direct connection between 100G devices, such as 100G switches, etc.; the QSFP28 to 4*SFP28 DAC high-speed cable is suitable for interconnection between 100G and 25G devices.

With the rapid growth of Internet data usage and the emergence of new high-bandwidth application services such as video on demand (VOD) and sharing, large data centers around the world are moving toward 100G links on servers in order to meet higher bandwidth demands and greater network capacity, to which the stacking between switches has been upgraded from the earlier 10Gbps to 100Gbps.

DAC high-speed cables in the rack connection scheme

DAC high-speed cables are generally used for short distance direct connections between data center racks internally, with lengths of 1 to 7 meters being optimal (up to 12 meters). If the length of the short distance within 12 ~ 30 meters can choose AOC active optical cable, more than 30 meters long distance can choose optical module + fiber patch cable combination.

If your wiring scenario is also short distance transmission, DAC high-speed cable is a good choice for cost reasons