QSFP-DD (Double Density QSFP): Something You Want to Know

With the rapid growth of data center and 5G development, density, power limits in servers, switches, and other network equipment are being pushed by rising demand and data volume. Data center is required to support faster processing, more bandwidth, and increased density without sacrificing reliability. In this situation, QSFP-DD came out, which is a new module and cage/connector system similar to current QSFP, but with an additional row of contacts providing for an eight lane electrical interface. In this article, we will introduce you something about QSFP-DD that you may be interested in.

1. What Is QSFP-DD?

QSFP-DD stands for Quad Small Form Factor Pluggable Double Density. What Double Density means? The “double density” means the doubling of the number of high-speed electrical interfaces that the module supports compared with a standard QSFP28 module. QSFP-DD is a “double-density” module and cage/connector system which is similar to the current QSFP system. But QSFP-DD has an additional row of contacts providing for an eight-lane electrical interface. The new optical module will be able to operate 25 Gb/s NRZ modulation or 50 Gb/s PAM4 modulation over 16 pairs of twinaxial conductors or optical fibers to support 200 Gb/s or 400 Gb/s aggregate bandwidth.

2. An Introduction on QSFP-DD MSA Group

QSFP-DD Specification for QSFP Double Density 8X Pluggable Transceiver is currently under development by the QSFP-DD MSA Group. The group includes 13 members which are all the leading vendors in the optical communication industry, like Cisco, Brocade and Finisar, aiming to create a upgraded version of QSFP transceiver, which is called QSFP-DD and is able to support 200G/400G Ethernet.
QSFP-DD MSA Group participants have developed an improved management interface. The MSA project may split into separate management interface and form-factor documents. There is a possibility that the OSFP MSA Group, the uQSFP MSA Group, and the Consortium for On-Board Optics (COBO) will adopt the improved QSFP-DD management interface.

3. QSFP-DD vs. QSFP28

QSFP28, with increased data rates ranging up to 28 Gbps on each of four lanes, supports next-generation 100 Gbps Ethernet and 100 Gbps InfiniBand. Now it is quite popular in datacenter computing, switches, routers, and storage. With enhanced Data Rate applications, the QSFP28 interconnect transmits up to 25 Gbps per-serial lane data rates with excellent signal integrity, EMI protection, and thermal cooling.
The QSFP-DD is similar to the current QSFP, but there are still some differences. If modulated by NEZ, each lane of the QSFP-DD can support data rate up to 25G, thus, it can support a total data rate of 200G. If modulated by PAM4, QSFP-DD transceiver can support data rate up to 400G with each lane supporting data rate of 50G. The MSA group also announced that the QSFP-DD can enable up to 14.4Tbps aggregate bandwidth in a single switch slot, which can definitely satisfy the increasing need for higher bandwidth.

4. 200G QSFP-DD

To achieve 400 Gbps, the interconnect industry is developing next-generation Quad Small Form Factor Pluggable Double Density (QSFP-DD) modules. And Gigalight also took the opportunity to release out the new 200G QSFP-DD in this summer. The 200G QSFP-DD integrates eight data lanes in each direction with 8x25.78125Gbps bandwidth. Each lane can operate at 25.78125Gbps up to 70m by using OM3 fiber or 100 m using OM4 fiber. The module is designed to operate over multimode fiber systems using a nominal wavelength of 850nm. It is a high performance module for short-range multi-lane data communication and interconnection applications. It is four-Channel, pluggable, parallel, fiber-optic QSFP+ SR4 for 100 or 40 Gigabit Ethernet, Infiniband FDR/EDR and applications. This transceiver is a high performance module for short-range multi-lane data communication and interconnects applications.

Conclusion

The QSFP-DD optical transceiver is also forward/backward compatible with QSFP, QSFP28 optical transceiver, AOC/DAC and so on. We believe that the rapid development of QSFP-DD will greatly benefit on the whole optical interconnect and communication industry. Let’s wait and see what will happen in the future.

CWDM and DWDM Comparison: What’s the Difference?

DWDM (Dense Wavelength Division Multiplexing) is undoubtedly the popular technology in today's optical fiber applications. However, because of its expensive price, many operators without enough money are quite hesitated to use it. Can we use wavelength division multiplexing at a lower cost? Faced with this demand, CWDM (Coarse Wavelength Division Multiplexing) came into being. And in the post, we will take an introduction on the main difference between CWDM and DWDM and which one is your better choice.

CWDM, as the name suggests, is a DWDM close relative. When comparing CWDM vs. DWDM, their differences are mainly two points as follows:
1. CWDM carrier channel spacing is wide, so the same fiber can only reuse 5 to 6 or so wavelength. This is why we call “Dense” and “Coarse”.
2. CWDM modulates laser by using non-cooling laser, but DWDM is used to cooling laser. The cooled laser is thermally tuned and the non-cooled laser is electronically tuned. Since the temperature distribution is very uneven in a wide wavelength range, the temperature tuning is difficult and costly to achieve. CWDM avoids this difficulty, therefore the cost is significantly reduced, the entire cost of CWDM system is only 30% of DWDM.
CWDM provides very high access bandwidth for low cost, and is suitable for popular network structures such as point-to-point, Ethernet, SONET ring, especially for short distance, high bandwidth, and point-intensive communication applications. Building communication between buildings or buildings. In particular, it is worth mentioning that CWDM and PON (passive optical network) with the use. PON is an inexpensive, point-to-multipoint optical fiber communication method. By combining with CWDM, each individual wavelength channel can be used as the virtual optical link of PON to realize the broadband data transmission between the central node and multiple distributed nodes.
At present, several companies are introducing CWDM-related products. Here we mainly introduce CWDM Mux/Demux and DWDM Mux/Demux.
(1). CWDM Mux/Demux Module:
CWDM Mux and CWDM Demux are designed to multiplex multiple CWDM channels into one or two fibers. The core of CWDM Module application is the passive MUX DEMUX unit. The common configuration is 1×4, 1×8, 1×16 channels. Available in 19″ Rack Mount or LGX module package, optional wide band port is available to multiplex with CWDM Channels wavelength.
(2). DWDM Mux/Demux Module:
DWDM Mux and DWDM DeMux are designed to multiplex multiple DWDM channels into one or two fibers. The common configuration is 4, 8, 16 and 40 channels. These modules passively multiplex the optical signal outputs from 4 or more electronic devices, send them over a single optical fiber and then de-multiplex the signals into separate, distinct signals for input into electronic devices at the other end of the fiber optic link.
However, CWDM is the product of cost and performance compromise; inevitably there are some limitations on performance. Industry experts pointed out that CWDM currently exist below the following four points: First, CWDM in a single fiber to support the number of multiplex wavelengths less, resulting in higher cost of expansion in the future; second, multiplexers, multiplexers, etc. The cost of the equipment should be further reduced, these devices can not only DWDM corresponding equipment, a simple modification; Third, CWDM does not apply to metropolitan area networks, metro nodes between the shorter distance, operators in the CWDM equipment expansion on the money can Used to lay more fiber optic cable, get better results; Fourth, CWDM has not yet formed a standard.
From the CWDM and DWDM comparison above, we can know both the benefits and drawbacks of CWDM and DWDM. If the transmission distance is short and cost is low, then CWDM may be your first choice. On the contrary, you can consider DWDM. For more information about CWDM and DWDM, you can visit: Gigalight.

Major Trends for 100G Ethernet Market

The Ethernet market has grown dramatically over the past few years. Speeding up transmission and expanding the capacity of the data center will help drive this trend. According to IHSInfonetics, 100 Gigabit Ethernet (100G) per second will account for more than 50% of the data center fiber optic transceivers market by 2019. Since 2014, the industry's revenue has increased by 21% to $ 1.4 billion. As the 100G chip is put into production, and 100G Ethernet market speculation is accelerating. But all this is just speculation; perhaps 100G Ethernet transceiver market will have a revolutionary progress?

1. Data Center Architecture and Traffic Changes

At present, the fiber industry's transmission technology reaches gigabits per second (10G) and 40 gigabits per second (40G), which has been around for a long time. These techniques are effective and most people have no objection to this. For most users, the 40G transmission speed is more than enough. The problem of data transmission in the data center becomes apparent. Internet content providers and enterprises in the cloud data on the scale and traffic will continue to grow.

Cisco Systems predicts that Internet data (IP) traffic in the global data center will grow at an annual rate of 31 percent over the next five years. The way people use the Internet changes to make this growth. Cloud computing data volume is growing, the global mobile device access to video social media content data more and more.

Data center construction is increasing, which requires a better data management solution. The influx of traffic has led to changes in the way in which the three-tier network and other changing information flows through the data center movement (ie, a combination of user interfaces, data processors, and database management systems). Newer technologies allow parallel processing and can transfer more data. The Internet is becoming more and more complexed, and websites need more interconnection. The architecture of the data center is changing, focusing more on the integration nodes and increasing the bandwidth. Obviously, 100G will become the new standard for higher bandwidth and smarter data center architecture.

2. 10G Cannot Meet the Growing Needs of the Enterprise Network

Some large data centers have been switched. The Howard Hughes Medical Institute has recently switched to 100G technologies, delivered via the Brocade MLXE router. The data center includes 56 11G ports, all equipped with its efficiency to achieve the highest priority of the switch. Traditionally, the data center will rely on 10G multiple bundles of transmission, requiring link aggregation, and resulting in suboptimal and inefficient load balancing.

This is the 100G useless. It releases space, minimizes data aggregation, and significantly improves overall efficiency. As the size of the enterprise grows and the demand for data becomes more complex, the 100G will provide them with the urgency of bandwidth and efficiency. Companies with four or five 10G ports have witnessed their database growth and may find switching to more affordable and scalable 100G ports. Of course, this is driven by the cost and the resources of the enterprise.

3. The Continuous Development of CMOS Technology Will Make 100 G Become Mainstreams

With the evolution of 10G technology, 100G technology into the mainstream before it takes some time to develop transceiver technology, when it began to use, the cost is expensive, requires a lot of power. With the passage of time, advances in chip technology have reduced more costs and the emergence of various energy-saving technologies. This is exactly 100G technology in the market to win the reasons, and the use of CMOS technology to become the industry standard. Because the use of CMOS architecture will make it faster, while using less power.

Once the technology is mature, the 100G system architecture can save more power and provide up to 10 times the speed. At present, Cisco and Brocade Communications Systems sell 100G switches and routers at the enterprise level. But the average cost per port of its switch is $ 2,500, which means that companies using 100G network to pay a high price. However, with the development of CMOS technology, the creation of these systems will become easier and more affordable. Many optical communication manufacturers, like Gigalight, launched various kinds of 100G products, such as 100G QSFP28. These systems will reduce costs, reduce data center size and power requirements, and make 100G applications mainstream.

Ethernet vs Internet: What's the Difference?

As we all know, both internet and Ethernet belong to types of networks that are used to connect computers.  However, to some degree, they differ in many aspects. Then if we want to compare Ethernet vs Internet, what are their differences? In this article, we will discuss it in detail.

  Internet is one of networks, composed of millions of ones from the local to the private, the governmental, the academic, and the corporate in the globe and connected by a series of techs, such as electronic tech, wireless tech, optical fiber network tech and so on. While  the Ethernet is the base LAN  standard created by Xerox, and jointly developed into the one by Xerox, Intel and DEC. It adopts the CSMA/CD access control method and is conformed to IEEE802.3.

  In fact, the difference between them has been shown from the introduction, but the difference between them i s far more than this. More differences are reflected in these respects.

What Is the Difference Between Internet and Ethernet?

  For one thing, in terms of connection range, compared with Ethernet, the connection range of internet is far wider than that of it. Ethernet belongs to one of Local Area Network(LAN), mainly responsible for the interconnections of computers in local areas. Generally speaking, the interconnections of computers in local areas usually happen in the same building or in the neighborhood. However, with the developments of Ethernet cables, the connection range of the Ethernet can be expanded to ten kilometers. Even so, in some sense, it's impractical to achieve the long-distance interconnection between computers. While internet belongs to one of Wide Area Network (WAN), able to connect networks all over the world.  The private, the governmental, the academic, and the corporate network in the globe are connected with each other to share massive information, resources and services.

  For another thing, they distinguish in the aspects of transmission media and tech. The Ethernet applies twisted pair and fiber as the transmission media and adopts CSMA/CD(Carrier Sense Multiple Access with Collision Detection )method. While internet doesn’t use some specific tech or transmission media, it contains all transmission medias  and techs.

  In addition, they also differ in respect of the network administration. Ethernet can have one or more administrators; while parts of internet are administrated by administrators, but there is no administrators  to control the whole internet.

  Finally, there are differences in security of network. By comparison, the Ethernet is with higher security than internet. External people have no access to it; while internet is accessible to all of people.

Article souce: www.gigalight.com

3 Types of SFP Transceivers That You Want to Know

There are many types of SFP transceivers in the current market. Gigalight supply various types of SFP module 100% compatible with Cisco SFP, HP SFP , Juniper SFP, Netgear SFP, DELL SFP CWDM SFP, DWDM SFP, BIDI SFP, 10G SFP and so on. For many SFP transceiver types, I will introduce three main types of SFP transceiver modules in detail.

1.       CWDM SFP Transceiver :

CWDM SFP (Small Form Factor Pluggable) transceiver is actually an optical transceiver compact used in communications optics both for applications in telecommunication and communication of data on the wavelength. CWDM SFP are widely used to link the ports of the network of fiber optics, typical CWDM SFP as Cisco could support both Gigabit Ethernet and Fiber Channel . CWDM SFP modules take advantage of the SFP interface for connecting the computer and use interface connector fiber PC LC double for the connection of the network optics. Gigalight CWDM SFP transceivers can be found with a number of different types of transmitter and receiver, allowing users to decide on the appropriate transceiver for each link to provide the required optical range over the available optical fiber.

2.       DWDM SFP Transceiver:

Dense wavelength multiplexing transceivers (DWDM Division) offer DWDM transport with far lower power and the cost of a standard SFP pluggable package. DWDM SFP is available in all wavelengths of 100 GHz C / L bandwidth of ITU DWDM network. As multifrequency user interfaces that support all protocols from 100 Mbps to 4.25 Gbps. The modules meet the requirements of the Gigabit Ethernet IEEE802.3 standard ANSI specifications and channel of fiber, they are suitable for interconnections in Gigabit Ethernet environments and channel of fiber. The DWDM SFP was created to accept DWDM SONET / SDH (with or without FEC) for 200 miles links and Ethernet / fiber protocol channel of traffic to the links 80 miles.

3.       10G SFP Transceiver :

The 10G SFP Transceiver Modules refers to 10G SFP Plus transceivers, It is known that sfp + is an enhanced version of the SFP that supports data rates up to 10 Gbit /s. Several standards 10G SFP has been set free, 10GBASE-SR is for fiber optic multimode OM3, SFP corresponding more distance work 300 meters max, 10GBASE-LR is fiber optic mode only, corresponding SFP more distance work of 10 km , 10GBASE-LRM is forFDDI multimode fiber , the SFP+ supports remote work of 220 meters .

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