market background
Innovative network technologies and endless network applications are driving the rapid development of the network. As a data center for centralized processing of information data and storage of network equipment, it has been facing the challenges of high bandwidth, high reliability, and low latency. According to the IDC Industry Development Research Report, as of 2011, the global IDC market maintained a steady growth trend. The overall market size reached US$22.26 billion, with a growth rate of 21.5%. Among them, emerging markets such as the Asia Pacific have become the biggest driving force for the growth of the entire industry. In 2-3 years, the Asia Pacific region will enter a period of high growth in data center deployment and upgrade. In China, many traditional data centers are built according to the standards of the 1990s. The reliability, energy consumption and refrigeration systems of the structure cannot meet the needs of expansion and upgrade, and face high energy consumption and high operating cost. At the same time, data center operators have just emerged from the economic crisis, paying more attention to cost and budget than ever before. Under the pressure of increasing business volume, data centers are seeking suitable and effective methods to upgrade and expand in a more economical way. The market trend of IDC and the problems faced by traditional data centers, the data center access layer from Gigabit to 10G will be an irreversible trend.
10G SFP+ DAC cable emerges
SFP (Small Form-factor Pluggables) is an upgraded version of GBIC (Gigabit Interface Converter). It is half the size of the GBIC module and functions in the same way as GBIC. It converts gigabit electrical signals into optical signals. The 10G module has undergone development from 300Pin, XENPAK, X2, and XFP, and finally realizes transmitting 10G signals in the same size as SFP. This is SFP+. SFP+ meets the high-density requirements of optical modules due to its advantages of miniaturization and low cost. It has been implemented since 2002 and has replaced XFP as the mainstream of the 10G market in 2010. The SFP is standardized by a protocol jointly developed by multiple vendors, and the SFP+ complies with the protocols: IEEE 802.3ae, SFF-8431, and SFF-8432.
Cable assemblies for interconnection between network cards (including interface modules at both ends) are called direct connection cables—–Direct Attach Cables (DAC). DAC cable assemblies are mainly used for stacking connections of Ethernet 10G switches, TOR switches. Interconnect with servers, Fibre Channel device interconnects, InfiniBand device interconnects and interconnects between servers/storage devices.
The SFP+ DAC is also known as 10GSFP+ copper, 10GBASE-CR or SFP+, 10GBASE-CX1, or 10GbE copper SFP cable. Direct connection, using a passive dual-axis cable assembly and directly connected to the SFP+ module. The SFP+ direct connection has a fixed length cable, usually 3, 5 or 7 meters in length, using a small cable and a small SFP+ module, with the advantages of low power, low cost and low latency.
SFP+ DAC straight cable
In the past, server vendors used the RJ45 port on the motherboard to be basically free, and now 10G ports are expensive, and pluggable port modules have become a cost barrier that cannot be ignored. Currently, there are three types of mainstream server NICs in 10G Ethernet data centers: 10G Base-CR SFP+ NICs. These optical NICs need to be connected to 10G SFP+ DAC (Direct Attach Cable) direct-connected copper components. There are also 10G Base-T copper network cards and 10G Base-SR optical network cards. The links using these three types of network cards are compared with the overall technology development state, and the optical link cost is about 1.3 times that of the copper link. The 10GBase-T copper network card uses the RJ45 interface. Currently, the network card sold in the market has relatively large power consumption. Many users are still waiting to see it. It is expected that the 10G Base-T power can be greatly reduced.
The server port rate is increased from 1 Gbps to 10 Gbps. The uplink of the access layer to the core trunk link is increased to 40 Gbps/100 Gbps. This is the basis for the network to achieve non-blocking full line rate. Since 2011, major manufacturers have launched the MSA specification 40G. Even switches with 100G interfaces. Each switch has at least 4-8 40G ports upstream and at least 24 10G ports down. In the past, many people thought that 40G is only a transition period of 100G. At present, in the overall environment, the cost of data center construction is tight, and the cost of the 40G optical link is more than 3-4 times that of 10G link. The cost of 100G optical links is higher. The 4x25Gbps 100G transceivers that originally adopted WDM technology are 250 times that of 10G transceivers. In particular, the cost of 100G single-mode optical links over 10km is even more prohibitive. Although the cost is gradually decreasing, the relative price is still high, at least the cost is reduced to 2-3 times of 40G, 5-6 times of 10G, can really enter the era of 100G. Therefore, at least in the next three years, 40G will become the mainstream trend of Ethernet server ports. The Ethernet Alliance released the “40G Ethernet and 100G Ethernet Technology Overview” in June 2010 for physical layer media: single mode fiber, OM3 and OM4 multimode fiber, backplane, copper cable, and corresponding interfaces. Analysis and given the corresponding requirements, such as duplex rate, transmission distance, bit error rate, maximum/minimum data frame.
40GQSFP+ to 4x10GSFP+ DAC direct-connected copper cable can convert the 40G port of the TOR access layer switch into four 10G channels to connect to the server port in the cabinet, which will be used in the server cabinet with the 10G SFP+ direct-connected copper cable. The 40GQSFP+ DAC direct-attached copper cable will be applied to the backbone link of the data center access layer network to the core network, but since the long distance of the 40GQSFP+ DAC direct-connected copper cable does not exceed 7 meters, for the general data center backbone link It is said that because the length limit is more difficult to apply, due to the cost advantage of 40GQSFP+ DAC direct copper cable, it can be partially considered for containerized data centers and high-speed stacking between devices. For the backbone link, in the current state of the art, more parallel multimode fiber links supporting longer distances will be required.
Conclusion:
The transmission applications of 10GSFP+ and 40GQSFP+ to 4x10GSFP+ DAC direct-attached cables between the access layer network and the server have been deployed on a large scale. Third-party market research organizations predict that by 2015, the market share of DAC direct-connected copper cables supporting 10G and above will be From $28 million in 2010 to $1.5 billion, DAC direct-connected copper will show a significant increase in the next 2-3 years, and will be around 30%-40% in future 10 Gigabit server port applications. market share. The 40GQSFP+ DAC direct-attached copper cable will be used in specific data centers or equipment stacks as well as in the industrial field due to the limitation of distance. The backbone of the data center will still be dominated by optical fiber for a long time to come. TIA and ISO standardization organizations are already developing solutions based on 40G copper cables to support 100 meters. We still need to wait for the development of copper 40G standardization. But for a 10G network, the DAC cable will be a 10 Gigabit solution that we can’t ignore. As a member of the International Organization for Standardization, Rosenberger has long been concerned about the development of network interface technology in the data center industry. With the advancement of technology and the development of the market, there will be new changes, as a professional data center cabling company. For users to choose different interface modes according to the actual needs of different planning of their own data center, no matter whether the user adopts an interface scheme, Rosenberg can provide corresponding product solutions and services.