400G Network Archives - Page 5 of 5 - Fiber Optical Networking

100G NIC: An Irresistible Trend in Next-Generation 400G Data Center

NIC, short for network interface card, which can be called network interface controller, network adapter or LAN adapter, allows a networking device to communicate with other networking devices. Without NIC, networking can hardly be done. There are NICs with different types and speeds, such as wireless and wired NIC, from 10G to 100G. Among them, 100G NIC, as a product appearing in recent years, hasn’t taken a large market share yet. This post gives a description of 100G NIC and the trends in NIC as follows.

What Is 100G NIC?

NIC is installed on a computer and used for communicating over a network with another computer, server or other network devices. It comes in many different forms but there are two main different types of NIC: wired NIC and wireless NIC. Wireless NICs use wireless technologies to access the network, while wired NICs use DAC cable or transceiver and fiber patch cable. The most popular wired LAN technology is Ethernet. In terms of its application field, it can be divided into computer NIC card and server NIC card. For client computers, one NIC is needed in most cases. However, for servers, it makes sense to use more than one NIC to meet the demand for handling more network traffic. Generally, one NIC has one network interface, but there are still some server NICs that have two or more interfaces built in a single card.

Figure 1: FS 100G NIC

With the expanding of data center from 10G to 100G, 25G server NIC has gained a firm foothold in the NIC market. In the meantime, the growth in demand for bandwidth is driving data center to higher bandwidth, 200G/400G and 100G transceivers have been widespread, which paves the way for 100G server.

How to Select 100G NIC?

How to choose the best 100G NIC from all the vendors? If you are stuck in this puzzle, see the following section listing recommendations and considerations to consider.

Connector

Connector types like RJ45, LC, FC, SC are commonly used connectors on NIC. You should check the connector type supported by NIC. Today many networks are only using RJ45, so it may be not that hard to choose the NIC for the right connector type as it has been in the past. Even so, some network may utilize a different interface such as coax. Therefore, check if the card you are planning to buy supports this connection before purchasing.

Bus Type

PCI is a hardware bus used for adding internal components to the computer. There are three main PCI bus types used by servers and workstations now: PCI, PCI-X and PCI-E. Among them, PCI is the most conventional one. It has a fixed width of 32 bits and can handle only 5 devices at a time. PCI-X is a higher upgraded version, providing more bandwidth. With the emergence of PCI-E, PCI-X cards are gradually replaced. PCI-E is a serial connection so that devices no longer share bandwidth like they do on a normal bus. Besides, there are different physical sizes of PCI-E card in the market: x16, x8, x4, and x1. Before purchasing a 100G NIC, it is necessary to make sure which PCI version and slot width can be compatible with your current equipment and network environment.

Hot swappable

There are some NICs that can be installed and removed without shutting down the system, which helps minimize downtime by allowing faulty devices to be replaced immediately. While you are choosing your 100G NIC, be sure to check if it supports hot swapping.

Trends in NIC

NICs were commonly used in desktop computers in the 1990s and early 2000s. Up to now, it has been widely used in servers and workstations with different types and rates. With the popularization of wireless networking and WiFi, wireless NICs gradually grows in popularity. However, wired cards are still popular for relatively immobile network devices owing to the reliable connections.NICs have been upgrading for years. As data centers are expanding at an unprecedented pace and driving the need for higher bandwidth between the server and switches, networking is moving from 10G to 25G and even 100G. Companies like Intel and Mellanox have launched their 100G NIC in succession.

During the upgrading from 10G to 100G in data centers, 25G server connectivity popularized for 100G migration can be realized by 4 strands of 25G. 25G NIC is still the mainstream. However, considering the fact that the overall bandwidth for data centers grows quickly and hardware upgrade cycles for data centers occur every two years, the ethernet speed can be faster than we expect. 400G data center is just on the horizon. It stands a good chance that 100G NIC will play an integral role in next-generation 400G networking.

Meanwhile, the need of 100G NIC will drive the demand for other network devices as well. For instance, 100G transceiver, the device between NIC and network, is bound to pervade. Now 100G transceivers are provided by many brands with different types such as CXP, CFP, QSFP28 transceivers,etc. FS supplies a full series of compatible 100G QSFP28 and CFP transceivers that can be matched with the major brand of 100G Ethernet NIC, such as Mellanox and Intel.

Conclusion

Nowadays with the hyping of the next generation cellular technology, 5G, the higher bandwidth is needed for data flow, which paves the way for 100G NIC. On the occasion, 100G transceivers and 400G network switches will be in great need. We believe that the new era of 5G networks will see the popularization of 100G NIC and change towards a new era of network performance.

Article Source: 100G NIC: An Irresistible Trend in Next-Generation 400G Data Center

400G QSFP Transceiver Types and Fiber Connections

How Many 400G Transceiver Types Are in the Market?

400G Transceiver, DAC, or AOC: How to Choose?

Due to the increasing growth in the demand for data centers and cloud computing, enterprises are eager for data centers with higher speed, larger bandwidth, and lower latency. In this case, 400G Ethernet has become an inevitable trend in data centers. With the advent of 400G technology, there are typically two options for 400G data center connectivity: 400G transceivers and 400G DAC/AOC.

400G Transceivers

400G transceivers are common solutions for 400G data center interconnection. According to different 400G transceiver form factors, there are CFP8, QSFP-DD, OSFP, COBO, etc., of which the most common type is QSFP-DD. These transceivers are different from each other in terms of transmission distance, connector, media and so on.

Usually, the SR8 module uses an MPO-16 connector to connect to 8 fiber pairs, realizing 400G transmission. The DR4 / XDR4 / PLR4 modules use an MPO-12 connector to connect to 4 fiber pairs. Unlike the SR8 and DR4, the FR4 optical modules use a duplex LC optical connector. And the FR8 modules (also called 2FR4 modules) use a dual CS connector to connect to 2 fiber pairs.

400G Cables: 400G DAC ＆ AOC

400G Direct Attached Cable (DAC) is suitable for very short-distance data center interconnection and it is cost-efficient. Besides, it uses copper cable as the transmission media. Typically, there are two types of DACs: passive copper cables for distance from 0 to 5m and active copper cables for distance from 5 to 15m.

Different from 400G DAC, 400G Active Optical Cable (AOC) uses fiber optical fiber as the transmission media. It is equivalent to using transceivers and separate cables. Besides, 400G AOCs support longer distance transmission than DACs, which can be up to 100m. They are also lighter and smaller than DACs, but they are more costly. Unlike DACs, AOCs are not affected by Electromagnetic Interference (EMI). You can check this article for more details on the 400G DAC and AOC.

Apart from 400G to 400G DAC/AOC, there are also 400G DAC/AOC breakout cables, such as 400G QSFP-DD to 4x100G QSFP56 DAC breakout cable, 400G QSFP-DD to 2x200G QSFP56 breakout AOC cable, and 400G QSFP-DD to 8x50G SFP56 DAC Breakout Cable. In this article, we’ll focus on 400G to 400G connection over 400G DAC/AOC.

Common 400G Transceiver/DAC/AOC Scenarios

Connectivity from ToR Switch to Server (Up to 2.5m)

400G DAC is the perfect solution for linked switches and servers inside racks. As shown in the figure above, 400G QSFP-DD DAC is used to connect 400G ToR switch and server in a 42U server cabinet. Because the height of the 42U server cabinet is only about 2 meters and 400G DAC is also cost-efficient, the 400G DAC becomes an ideal solution for short-distance transmission inside cabinet.

Connectivity from EoR Switch to Server (Up to 30m)

The 400G AOC usually connects switches and servers between racks in a data center. As the picture above shows, the 400G EoR switch is connected to the server rack and aggregation rack through 400G QSFP-DD AOC. Since the 400G AOC uses optical fiber as the transmission media, it can achieve longer distance transmission and higher bandwidth than the 400G DAC. Besides, it is also used to connect separate switches to create a larger switch architecture.

Connectivity from ToR Switch to Server (Up to 100m)

400GBASE-SR8 QSFP-DD transceivers can be used for leaf-spine switches interconnection and the transmission distance can reach 100m over OM4 MMF with MTP/MPO-16 connector.

Connectivity from ToR Switch to Server (Up to 150m)

Different from 400GBASE-SR8 QSFP-DD transceivers, the 400GBASE-SR4.2 QSFP-DD transceivers support 150m distance transmission over MPO/MTP-12 OM5 MMF.

Connectivity from ToR Switch to Server (Up to 500m)

400GBASE-DR4 QSFP-DD transceivers support up to 500m transmission distance over OS2 SMF with MPO/MTP-12 connector.

Data Center Interconnection (up to 2-120km)

Up to 2km: Usually, the data center interconnection needs transceivers that support longer distance and higher bandwidth transmission. 400GBASE-FR4 QSFP-DD transceivers support link lengths of up to 2km over OS2 SMF with duplex LC connector.
Up to 10km: For data center interconnection over 2km, 400GBASE-LR8 QSFP-DD transceiver is a better choice. It can support data transmission distances of up to 10km over OS2 SMF.
Up to 40km: 400GBASE-ER8 QSFP-DD enables link lengths of up to 40km over OS2 SMF with duplex LC connectors. Besides, it also features low-power, high-density and high-speed, which is a high-efficient option for 400G data center interconnection. However, it uses EML laser, APD detector, and also needs to use Mux combiner and Demux splitter, which leads to high cost.
Up to 120km: As for hyperscale data center interconnection, only 400G-ZR CSFP Coherent optical modules can meet the demands, supporting OS2 SMF transmission distances up to 120km.

Conclusion

In conclusion, 400G transceivers and 400G AOC and DAC cables are effective choices for the 400G data center connectivity. Both 400G AOC and DAC are more suitable for short distance transmission. However, the 400G AOC supports higher data transfer speed, while the 400G DAC is more cost-efficient. As for 400G transceivers, the application scenarios are more abundant. Data center operators should make appropriate choices based on their actual needs.

Article Source:

https://community.fs.com/blog/400g-transceiver-dac-or-aoc-how-to-choose.html

https://community.fs.com/blog/faqs-about-fs-400g-transceivers.html

https://community.fs.com/blog/faqs-on-400g-transceivers-and-cables.html

What’s the Current and Future Trend of 400G Ethernet?

According to the leading Cloud Service Providers (CSPs) and various networking forecast reports, 400G Ethernet will emerge as the leading technology since 2020. IDC (International Data Corporation) and Cignal Ai have also proved the similar situation. In short, 400G Ethernet will replace 100G and 200G deployments in a faster way than 100G did to the previous Ethernet.

Faster 400G Ethernet Trend Than Previous Ethernet.jpg

The Rise of 400G Ethernet

The factors affecting the development of 400G are mainly application-driven and technology-driven. The application drivers include 5G high-speed transmission, market requirements for data centers, cloud computing, and high-definition video transmission. Technology drivers include development of technologies in the market and product standardization.

Application-Driven Factors

5G Accelerates 400G Ethernet: An analysis from Cisco points out that 5G technology needs edge computing architecture, which brings cloud resources—compute, storage and networking—closer to applications, devices and users. While, the edge computing needs more bandwidth, support for more devices on the network, and greater security to protect and manage the data. For example, a 4G radio system can support up to only 2,000 active devices in a square kilometer, while 5G could support up to 100,000 active devices in the same range. With 400G technology offering more bandwidth, more devices and applications could be supported in 5G.

ITEMS	4G LTE	5G
Average Data Rate	25 Mb/s	100 Mb/s
Peak Data Rate	150 Mb/s	10,000 Mb/s
Latency	50 ms	1 ms
Connection Density	2,000 Per Square Kilometer	100,000 Per Square Kilometer

Data Center & Cloud Computing Requirements: A research from Cisco indicates that cloud-based data centers will take over 92% of the next-generation data center workload while the traditional data centers will take over less than 8% after 2021. These objective requirements for higher data rates drive 400G development greatly. It is estimated that 400G will be the prevailing speed in switch chips and network platforms in the coming years.
High-Definition Video Transmission Needs: Basically all forms of Internet applications are moving towards video. It is estimated that more than 80% of the traffic is video. Video is a very important platform for everyone to interact in the future, especially real-time video streaming, such as multi-party video conferences. High-definition videos (such as 4K videos) need more bandwidth and less latency compared with the previous normal ones featuring lower definition.

Technology-Driven Factors

400G technology was originally known as IEEE 802.3bs and was officially approved in December, 2017. It regulates new standards including Forward Error Correction (FEC) to improve error performance. Abide by these standards, early 400G network elements have successfully completed trials and initial deployment. At present, some brand 400G switches have been put into use such as Cisco 400G Nexus, Arista 400G 7060X4 Series, Mellanox Spectrum-2, FS 400G switch, etc. 400G connection scheme is also blooming such as 400G DAC and 400G transceivers (400G QSFP-DD transceiver, 400G OSFP transceiver, 400G CFP8 transceiver, etc.), of which 400G QSFP-DD is becoming the leading form factor for its high density and low power consumption. As 400G Ethernet grows faster to standardization, commercialization and scale, soon 400G product system will be gradually perfect and more 400G products will appear in return.

Influences of 400G Ethernet

400G Optics Promotes 25G and 100G Markets While Reduces 200G Market Share

Compared to the 10G Ethernet, 25G Ethernet gains more popularity in the whole optical transmission industry because 25Gbps and 50Gbps per channel technology provide the basic standards for existing 100G (4x 25Gbps), the coming 400G (8x 50Gbps) and the future 800G network. Therefore, the rapid development of 400G Ethernet will promote the 25G and 100G markets to a certain extent in turn. Similarly, the quick appearance of 400G applications implicates that 200G is a flash in the pan.

400G Technology Is Expected to Reduce Overall Network Operation and Maintenance Costs

For access, metro, and data center interconnection scenarios, where short transmission distance and higher bandwidth are required, fiber resources are relatively scarce. The single-carrier 400G technology can provide the largest transmission bandwidth and the highest spectral efficiency with the simplest configuration, which effectively reduces transmission costs.
In the backbone and some more complex metropolitan area networks, where the transmission distance is longer with more network nodes, the requirements for transmission performance are more stringent. Under such circumstances, dual-carrier technology (2x 200G) and an optimized algorithm could work together to compress the channel spacing. This can not only improve the spectral efficiency by 30% (close to the level of a single-carrier 400G technology), but also extend the transmission distance of 400G Ethernet to several thousand kilometers, helping operators quickly deploy 400G backbone networks with minimum bandwidth resources.
400G solution can also increase the single fiber capacity by 40% and reduce power consumption by 40%, thereby greatly improving network performance and reducing network operation and maintenance costs.

Opportunities for 400G Ethernet Vendors and Users

Many suppliers hype their 400G products to get ahead of the curve. Actually, few vendors have the real supply capacity and the quality of most 400G products supplied can’t be assured. To win from the fierce market competition, vendors should pay more attention to improving product quality and strong supply capability. And this is indubitably beneficial to users, who can get better products and services with relatively lower prices.

Impact of 400G Optics on Cabling and Connectivity

In the multimode installed base, the biggest difference between 100G and 400G modules is the increase in total number of fibers. For single mode transmission system, most of the duplex LC and MPO-based architecture that is deployed at 100G should serve for 400G. For parallel or multi-fiber transmission, transceivers like 400GBASE-SR4.2 operating with short wavelength division multiplexing (SWDM) at four wavelengths provide longer distances over OM5 fiber than OM4 or OM3. And OM5 wideband multimode fiber (WBMMF) will allow use of SWDM technology to transmit multiple signals (wavelengths) on one fiber. This indicates that OM5 fiber and SWDM technologies will continue to offer improved support on 400G Ethernet.

Are You Ready for 400G Ethernet?

400G Ethernet is an inevitable trend in current networking market. Driven by various market demands and technologies, it has come more rapidly than any previous technology. And it also has many significant effects, such as reducing the market share of 200G and saving transmission costs to a certain extent. There are already some mature 400G optics products in the market, such as 400G QSFP-DD transceivers, 400G DACs, as well as 400G DAC breakout cables. And 400G technology is no doubt going to be more and more advanced to promote the developments of 400G Ethernet and 400G applications.

Original Source: What’s the Current and Future Trend of 400G Ethernet?

NRZ vs. PAM4 Modulation Techniques

The leading trends such as cloud computing and big data drive the exponential traffic growth and the rise of 400G Ethernet. Data center networks are facing a larger bandwidth demand, and innovative technologies are required for infrastructure to meet shifting demands. Currently, there are two different signal modulation techniques examined for next-generation Ethernet: non-return to zero (NRZ), and pulse-amplitude modulation 4-level (PAM4). This article will take you through these two modulation techniques and compare them to find the optimal choice for 400G Ethernet.

NRZ and PAM4 Basics

NRZ is a modulation technique using two signal levels to represent the 1/0 information of a digital logic signal. Logic 0 is a negative voltage, and Logic 1 is a positive voltage. One bit of logic information can be transmitted or received within each clock period. The baud rate, or the speed at which a symbol can change, equals the bit rate for NRZ signals.

PAM4 is a technology that uses four different signal levels for signal transmission and each symbol period represents 2 bits of logic information (0, 1, 2, 3). To achieve that, the waveform has 4 different levels, carrying 2 bits: 00, 01, 10 or 11, as shown below. With two bits per symbol, the baud rate is half the bit rate.

Comparison of NRZ vs. PAM4

Bit Rate

A transmission with NRZ mechanism will have the same baud rate and bitrate because one symbol can carry one bit. 28Gbps (gigabit per second) bitrate is equivalent to 28GBdps (gigabaud per second) baud rate. While, because PAM4 carries 2 bits per symbol, 56Gbps PAM4 will have a line transmission at 28GBdps. Therefore, PAM4 doubles the bit rate for a given baud rate over NRZ, bringing higher efficiency for high-speed optical transmission such as 400G. To be more specific, a 400 Gbps Ethernet interface can be realized with eight lanes at 50Gbps or four lanes at 100Gbps using PAM4 modulation.

Signal Loss

PAM4 allows twice as much information to be transmitted per symbol cycle as NRZ. Therefore, at the same bitrate, PAM4 only has half the baud rate, also called symbol rate, of the NRZ signal, so the signal loss caused by the transmission channel in PAM4 signaling is greatly reduced. This key advantage of PAM4 allows the use of existing channels and interconnects at higher bit rates without doubling the baud rate and increasing the channel loss.

Signal-to-noise Ratio (SNR) and Bit Error Rate (BER)

According to the following figure, the eye height for PAM4 is 1/3 of that for NRZ, causing the PAM4 to increase SNR (Signal-Noise Ratio) by -9.54 dB (Link Budget Penalty), which impacts the signal quality and introduces additional constraints in high-speed signaling. The 33% smaller vertical eye opening makes PAM4 signaling more sensitive to noise, resulting in a higher bit error rate. However, PAM4 was made possible because of forward-error correction (FEC) that can help link system to achieve the desired BER.

Power Consumption

Reducing BER in a PAM4 channel requires equalization at the Rx end and pre-compensation at the Tx end, which both consume extra power than the NRZ link for a given clock rate. This means PAM4 transceivers generate more heat at each end of the link. However, the new state-of-the-art silicon photonics (SiPh) platform can effectively reduce energy consumption and can be used in 400G transceivers. For example, FS silicon photonics 400G transceiver combines SiPh chips and PAM4 signaling, making it a cost-effective and lower power consumption solution for 400G data center.

Shift from NRZ to PAM4 for 400G Ethernet

With massive data transmitted across the globe, many organizations pose their quest for migration towards 400G. Initially, 16× 25G baud rate NRZ is used for 400G Ethernet, such as 400G-SR16, but the link loss and size of the scheme can not meet the demands of 400G Ethernet. Whereas PAM4 enables higher bit rates at half the baud rate, designers can continue to use existing channels at potential 400G Ethernet data rates. As a result, PAM4 has overtaken NRZ as the preferred modulation method for electrical or optical signal transmission in 400G optical modules.

Article Source: NRZ vs. PAM4 Modulation Techniques