Common DAC high-speed cable classification and model

DAC high-speed cable (Direct Attach Cable) is generally translated as direct cable, direct-attached copper cable or high-speed cable. Its definition is a low-cost short-distance connection scheme that replaces optical modules. Cable components, non-replaceable ports, module heads and copper cables cannot be separated, but compared to Active Optical Cables (Active Optical Cables), the connector modules on high-speed cables do not have expensive optical lasers and other electronic components. It greatly saves cost and power consumption in short-distance applications. With higher Ethernet speeds, cloud computing, Internet of Things, and virtual data centers, more requirements are placed on data center operators. The data speed is actually on the way to 400G, so in addition to the connection within 3-5m in the server, DAC can also be used (5-7m requires special insulating materials to achieve the characteristic requirements). Connections beyond these distances are generally realized through AOC.

10G SFP+ to SFP+ high-speed cable
The 10G SFP+ to SFP+DAC uses passive twin-axial cable assemblies and is directly connected to the SFP+ module, which has the characteristics of high density, low power, low cost and low latency.
What types of 10G SFP+ to SFP+ high-speed cables are there?
Generally speaking, there are three types of 10G 10G SFP+ to SFP+ high-speed cables:
10G SFP+ passive copper core high-speed cable (DAC),
10G SFP+ active copper core high-speed cable (ACC),
10G SFP+ active optical cable (AOC),
They are suitable for network connections within a rack and between adjacent racks and are extremely cost-effective.
The SFP+ passive copper core high-speed cable provides a direct electrical interface between the two ends of the corresponding cable. The connection distance can reach 12m. However, due to the large weight of the cable and the signal integrity issues, its use length Generally limited between 7m and 10m.

40G QSFP+ to QSFP+ high-speed cable
40G high-speed cable (DAC) refers to a connection cable with fiber optic transceivers at both ends, which can realize 40Gbps data transmission, and is a highly cost-effective high-speed interconnection solution. 40G high-speed cables are more common and can be divided into three types: 40G QSFP+ to QSFP+DAC, 40GQSFP+ to 4*SFP+DAC, 40GQSFP+ to 4XFP+DAC, and the first two types are more practical in practical applications:
40G QSFP+ to QSFP+DAC is composed of two 40G QSFP+ optical fiber transceivers and copper core wires. This high-speed cable can be used to realize the interconnection from the existing 40G QSFP+ port to the 40G QSFP+ port. Generally, it can only be made within 7m distance.
40G QSFP+ to 4×SFP+ DAC is composed of 1 40G QSFP+ fiber optic transceiver, copper core wire and 4 10G SFP+ fiber optic transceivers. One end is 40G QSFP+ interface, which meets SFF-8436 requirements, and the other end is 4 10G SFP+ interfaces , Meet the requirements of SFF-8432, mainly used to realize the interconnection between 40G and 10G equipment (NIC/HBA/CNA, switch equipment and server), according to the customer's requirements for the cable length at both ends, generally only within 7m The distance is currently the most economical and simple to achieve switch port conversion.
40G QSFP+ to 4XFP DAC is composed of 1 40G QSFP+ optical fiber transceiver, copper core wire and 4 10G XFP optical fiber transceivers. Since XFP fiber optic transceivers do not have the DAC copper cable standard, the signal compensation provided by the equipment is low, and the cable itself has a large loss, which can only be used for short-distance transmission, generally only within 2m. Therefore, this high-speed cable can be used Realize the interconnection of the existing 40G QSFP+ port to 4 XFP ports.

25G SFP28 to SFP28 high-speed cable
25G SFP28 to SFP28 DAC can provide customers with 25G high-bandwidth data interconnection capabilities. It conforms to IEEE P802.3by Ethernet standard and SFF-8402 SFP28. It is widely used in data centers or supercomputer center system scenarios.

100G QSFP28 to QSFP28 high-speed cable
The 100G QSFP28 to QSFP28 DAC can provide customers with 100G high-bandwidth data interconnection capabilities, providing 4 duplex channels, each channel can support up to 25Gb/s working rate, and the aggregate bandwidth is 100Gb/s. It conforms to the SFF-8436 specification. Connection between devices with QSFP28 ports.
100G QSFP28 to 4*SFP28 high-speed cable
One end of the 100G QSFP28 to 4 SFP28 DAC is a 100G QSFP28 interface, and the other end is 4 25G SFP28 interfaces, which can provide customers with 100G high-bandwidth data interconnection capabilities, complying with SFF-8665/SFF-8679, IEEE 802.3bj and InfinibandEDR standards, Widely used in data center or supercomputing center system scenarios