40G Direct Attach Cable--The Milestone of High-speed Communications Development-seesuo

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40G Direct Attach Cable--The Milestone of High-speed Communications Development

2017-03-22

In the background of the rapid development of telecommunications industry and network technology, achieving the low-cost and high-efficiency high-speed interconnect solutions has become the driving force for the development of the telecommunications industry. Nowadays, in order to meet the needs of high-speed communication, direct attach cable has become a hot topic of cloud storage, cloud computing, super computer systems etc.

Direct Attach Cable is called DAC for short, which is a connect cable for communication equipment, generally used for achieving short-distance interconnect communication, is a very cost-effective high-speed interconnect solution. DAC has only experienced several years that developed from 10G to 40G, so that it can be seen that how fast the development of high-speed data communications. So now, let us talk about the 40G direct attach cable which is still popular today.

40G DAC is refers to the copper cable which installed optical modules at the both of end to reach 40Gbps data transmission. Now, there are 3 types of 40G DAC are mainly used in the market: 40G QSFP+ to QSFP+ DAC, 40G QSFP+ to 4*SFP+ DAC and 40G QSFP+ to 4*XFP+ DAC. There are two types of cable: active copper cable and passive copper cable. However, there is one thing supposed to be further explained: the optical modules of the direct attach cable are not real, because they have no components, just used for transmitting signal.

Why does 40G direct attach cable use QSFP + interface?

QSFP+ is a new generation hot pluggable interface which used in the high-performance switches, routers, servers and host bus adapters of computing and telecommunication applications. This kind of interface is the most compact and independent 4-channel pluggable interface, support the transmission rate of up to 40Gbps (4-channel x 10Gbps), and backward compatible with 5Gbps, 2.5Gbps data transmission rate. 40GBase QSFP+ applicable to short-distance stack and set between QSFP equipment.

40G QSFP+ to QSFP+ DAC can be divided into QSFP+ to QSFP+ passive copper cable and QSFP+ to QSFP+ active copper cable. These two kinds of direct attach cable composed of two 40G QSFP+ optical transceivers and copper cable. Differently, active cable has a drive chipset while passive cable has no. User can use these cables to achieve the interconnect from 40G QSFP+ interface to 40G QSFP+ interface

40G QSFP+ to 4* SFP+ DAC have only one type: 40G QSFP+ to 4*SFP+ passive copper cable, which is made up of 40G QSFP+ optical transceiver + copper cable + 4 x 10G SFP+ optical transceivers, mainly used for achieving the interconnect between 40G and 10G equipment (NIC/HBA/CAN, switches and servers). User can use these cables to achieve the interconnection from 40G QSFP+ interface to 40G QSFP+ interface.