How 400G Ethernet Influences Enterprise Networks?

Since the approval of its relevant 802.3bs standard from the IEEE in 2017, 400GbE Ethernet has become the talk of the town. The main reason behind it is the ability of this technology to beat the existing solutions by a mile. With its implementation, the current data transfer speeds will simply see a fourfold increase. Vigorous efforts are being made by the cloud service providers and network infrastructure vendors to pace up the deployment. However, there are a number of challenges that can hamper its effective implementation and hence, the adoption.

In this article, we will have a detailed look into the opportunities and the challenges linked to the successful implementation of 400G Ethernet enterprise network. This will provide a clear picture of the impact this technology will have on large-scale organizations.

Opportunities for 400G Ethernet Enterprise Networks

  • Better management of the traffic over video streaming services
  • Facilitates IoT device requirements
  • Improved data transmission density

How can 400G Ethernet assist enterprise networks in handling growing traffic demands?

Rise of 5G connectivity

Rising traffic and bandwidth demands are compelling the CSPs for rapid adoption of 5G both at the business as well as the customer end. A successful implementation requires a massive increase in bandwidth to cater for the 5G backhaul. In addition, 400G can provide CSPs with a greater density in small cells development. 5G deployment requires the cloud data centers to be brought closer to the users as well as the devices. This streamlines the edge computing (handling time-sensitive data) part, which is another game-changer in this area.5G

Data Centers Handling Video Streaming Services Traffic

The introduction of 400GbE Ethernet has brought a great opportunity for the data centers working behind the video streaming services as Content Delivery Networks. This is because the growing demand for bandwidth is going out of hand using the current technology. As the number of users increased, the introduction of better quality streams like HD and 4K has put additional pressure on the data consumption. Therefore, the successful implementation of 400GbE would come as a sigh of relief for the data centers. Apart from rapid data transferability, issues like jitter will also be brought down. Furthermore, large amounts of data transfer over a single wavelength will also bring down the maintenance cost.

High-Performance Computing (HPC)

The application of high-performance computing is in every industry sub-vertical whether it is healthcare, retail, oil & gas or weather forecasting. Real-time analysis of data is required in each of these fields and it is going to be a driver for the 400G growth. The combined power of HPC and 400G will bring out every bit of performance from the infrastructure leading to financial and operational efficiency.400G Ethernet

Addressing the Internet of Things (IoT) Traffic Demands

Another opportunity that resides in this solution is for the data centers to manage IoT needs. Data generated by the IoT devices is not large; it is the aggregation of the connections that actually hurts. Working together, these devices open new pathways over internet and Ethernet networks which leads to an exponential increase in the traffic. A fourfold increase in the data transfer speed will make it considerably convenient for the relevant data centers to gain the upper hand in this race.

Greater Density for Hyperscale Data Centers

In order to meet the increasing data needs, the number of data centers is also seeing a considerable increase. A look at the relevant stats reveals that 111 new Hyperscale data centers were set up during the last two years, and 52 out of them were initiated during peak COVID times when the logistical issues were also seeing an unprecedented increase. In view of this fact, every data center coming to the fore is looking to setup 400GbE. Provision of greater density in fiber, racks, and switches via 400GbE would help them incorporate huge and complex computing and networking requirements while minimizing the ESG footprint at the same time.

Easier Said Than Done: What Are the Challenges In 400G Ethernet technology

Below are some of the challenges enterprise data centers are facing in 400G implementation.

Cost and Power Consumption

Today’s ecosystem of 400G transceivers and DSP are power-intensive. Currently, some transceivers don’t support the latest MSA. They are developed uniquely by different vendors using their proprietary technology.

Overall, the aim is to reduce $/gigabit and watts/gigabit.

The Need for Real-World Networking Plugfests

Despite the standard being approved by IEEE, a number of modifications still need to be made in various areas like specifications, manufacturing, and design. Although the conducted tests have shown promising results, the interoperability needs to be tested in real-world networking environments. This would outline how this technology is actually going to perform in enterprise networks. In addition, any issues faced at any layer of the network will be highlighted.

Transceiver Reliability

Secondly, transceiver reliability also comes as a major challenge in this regard. Currently, the relevant manufacturers are finding it hard to meet the device power budget. The main reason behind that is the use of a relatively older design of QSFP transceiver form factor as it was originally designed for 40GbE. Problems in meeting the device power budget lead to issues like heating, optical distortions, and packet loss.

The Transition from NRZ to PAM-4

Furthermore, the shift from binary non-return to zero to pulse amplitude modulation with the introduction of 400GbE also poses a challenge for encoding and decoding. This is because NRZ was a familiar set of optical coding whereas PAM-4 requires involvement of extensive hardware and an enhanced level of sophistication. Mastering this form of coding would require time, even for a single manufacturer.from NRZ to PAM-4

Greater Risk of Link Flaps

Enterprise use of 400GbE also increases the risk of link flaps. Link flaps are defined as the phenomenon involving rapid disconnection in an optical connection. Whenever such a scenario occurs, auto-negotiation and link-training are performed before the data is allowed to flow again. While using 400GbE, link flaps can occur due to a number of additional reasons like problems with the switch, design problems with the -transceiver, or heat.

Inference

The true deployment of 400GbE Ethernet enterprise network is undoubtedly going to ease management for cloud service providers and networking vendors. However, it is still a bumpy road. With the modernization and rapid advancements in technology, scalability is going to become a lot easier for the data centers. Still, we are still a long way from the destination of a successful implementation. With higher data transfer rates easing traffic management, a lot of risks to the fiber alignment and packet loss still need to be tackled.

Article Source: How 400G Ethernet Influences Enterprise Networks?

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Coherent Optics and 400G Applications

In today’s high-tech and data-driven environment, network operators face an increasing demand to support the ever-rising data traffic while keeping capital and operation expenditures in check. Incremental advancements in bandwidth component technology, coherent detection, and optical networking have seen the rise of coherent interfaces that allows for efficient control, lower cost, power, and footprint.

Below, we have discussed more about 400G, coherent optics, and how the two are transforming data communication and network infrastructures in a way that’s beneficial for clients and network service providers.

What is 400G?

400G is the latest generation of cloud infrastructure, which represents a fourfold increase in the maximum data-transfer speed over the current maximum standard of 100G. Besides being faster, 400G has more fiber lanes, which allows for better throughput (the quantity of data handled at a go). Therefore, data centers are shifting to 400G infrastructure to bring new user experiences with innovative services such as augmented reality, virtual gaming, VR, etc.

Simply put, data centers are like an expressway interchange that receives and directs information to various destinations, and 400G is an advancement to the interchange that adds more lanes and a higher speed limit. This not only makes 400G the go-to cloud infrastructure but also the next big thing in optical networks.

400G

What is Coherent Optics?

Coherent optical transmission or coherent optics is a technique that uses a variation of the amplitude and phase or segment of light and transmission across two polarizations to transport significantly more information through a fiber optic cable. Coherent optics also provides faster bit rates, greater flexibility, modest photonic line systems, and advanced optical performance.

This technology forms the basis of the industry’s drive to embrace the network transfer speed of 100G and beyond while delivering terabits of data across one fiber pair. When appropriately implemented, coherent optics solve the capacity issues that network providers are experiencing. It also allows for increased scalability from 100 to 400G and beyond for every signal carrier. This delivers more data throughput at a relatively lower cost per bit.

Coherent

Fundamentals of Coherent Optics Communication

Before we look at the main properties of coherent optics communication, let’s first understand the brief development of this data transmission technique. Ideally, fiber-optic systems came to market in the mid-1970s, and enormous progress has been realized since then. Subsequent technologies that followed sought to solve some of the major communication problems witnessed at the time, such as dispersion issues and high optical fiber losses.

And though coherent optical communication using heterodyne detection was proposed in 1970, it did not become popular because the IMDD scheme dominated the optical fiber communication systems. Fast-forward to the early 2000s, and the fifth-generation optical systems entered the market with one major focus – to make the WDM system spectrally efficient. This saw further advances through 2005, bringing to light digital-coherent technology & space-division multiplexing.

Now that you know a bit about the development of coherent optical technology, here are some of the critical attributes of this data transmission technology.

  • High-grain soft-decision FEC (forward error correction):This enables data/signals to traverse longer distances without the need for several subsequent regenerator points. The results are more margin, less equipment, simpler photonic lines, and reduced costs.
  • Strong mitigation to dispersion: Coherent processors accounts for dispersion effects once the signals have been transmitted across the fiber. The advanced digital signal processors also help avoid the headaches of planning dispersion maps & budgeting for polarization mode dispersion (PMD).
  • Programmability: This means the technology can be adjusted to suit a wide range of networks and applications. It also implies that one card can support different baud rates or multiple modulation formats, allowing operators to choose from various line rates.

The Rise of High-Performance 400G Coherent Pluggables

With 400G applications, two streams of pluggable coherent optics are emerging. The first is a CFP2-based solution with 1000+km reach capability, while the second is a QSFP DD ZR solution for Ethernet and DCI applications. These two streams come with measurement and test challenges in meeting rigorous technical specifications and guaranteeing painless integration and placement in an open network ecosystem.

When testing these 400G coherent optical transceivers and their sub-components, there’s a need to use test equipment capable of producing clean signals and analyzing them. The test equipment’s measurement bandwidth should also be more than 40-GHz. For dual-polarization in-phase and quadrature (IQ) signals, the stimulus and analysis sides need varying pulse shapes and modulation schemes on the four synchronized channels. This is achieved using instruments that are based on high-speed DAC (digital to analog converters) and ADC (analog to digital converters). Increasing test efficiency requires modern tools that provide an inclusive set of procedures, including interfaces that can work with automated algorithms.

Coherent Optics Interfaces and 400G Architectures

Supporting transport optics in form factors similar to client optics is crucial for network operators because it allows for simpler and cost-effective architectures. The recent industry trends toward open line systems also mean these transport optics can be plugged directly into the router without requiring an external transmission system.

Some network operators are also adopting 400G architectures, and with standardized, interoperable coherent interfaces, more deployments and use cases are coming to light. Beyond DCI, several application standards, such as Open ROADM and OpenZR+, now offer network operators increased performance and functionality without sacrificing interoperability between modules.

Article Source:Coherent Optics and 400G Applications

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400G Multimode Fiber: 400G SR4.2 vs 400G SR8

Cloud and AI applications are driving demand for data rates beyond 100 Gb/s, moving to high-speed and low-power 400 Gb/s interconnects. The optical fiber industry is responding by developing two IEEE 400G Ethernet standards, namely 400GBASE-SR4.2 and 400GBASE-SR8, to support the short-reach application space inside the data center. This article will elaborate on the two standards and their comparison.

400GBASE-SR4.2

400GBASE-SR4.2, also called 400GBASE-BD4.2, is a 4-pair, 2-wavelength multimode solution that supports reaches of 70m (OM3), 100m (OM4), and 150m (OM5). It is not only the first instance of an IEEE 802.3 solution that employs both multiple pairs of fibers and multiple wavelengths, but also the first Ethernet standard to use two short wavelengths to double multimode fiber capacity from 50 Gb/s to 100 Gb/s per fiber.

400GBASE-SR4.2 operates over the same type of cabling used to support 40GBASE-SR4, 100GBASE-SR4 and 200GBASE-SR4. It uses bidirectional transmission on each fiber, with each wavelength traveling in opposite directions. As such, each active position at the transceiver is both a transmitter and a receiver, which means 400GBASE-SR4.2 has eight optical transmitters and eight optical receivers in a bidirectional optical configuration.

The optical lane arrangement is shown as follows. The leftmost four positions labeled TR transmit wavelength λ1 (850nm) and receive wavelength λ2 (910nm). Conversely, the rightmost four positions labeled RT receive wavelength λ1 and transmit wavelength λ2.

400GBASE-SR4.2 fiber interface

400GBASE-SR8

400GBASE-SR8 is an 8-pair, 1-wavelength multimode solution that supports reaches of 70m (OM3), 100m (OM4 & OM5). It is the first IEEE fiber interface to use eight pairs of fibers. Unlike 400GBASE-SR4.2, it operates over a single wavelength (850nm) with each pair supporting 50 Gb/s transmission. In addition, it has two variants of optical lane arrangement. One variant uses the 24-fiber MPO, configured as two rows of 12 fibers, and the other interface variant uses a single-row MPO-16.

400GBASE-SR8 fiber interface variant 1
400GBASE-SR8 fiber interface variant 2

400GBASE-SR8 offers flexibility of fiber shuffling with 50G/100G/200G configurations. It also supports breakout at different speeds for various applications such as compute, storage, flash, GPU, and TPU. 400G-SR8 QSFP DD/OSFP transceivers can be used as 400GBASE-SR8, 2x200GBASE-SR4, 4x100GBASE-SR2, 8x50GBASE-SR.

400G SR4.2 vs. 400G SR8

As multimode solutions for 400G Ethernet, 400GBASE-SR4.2 and 400GBASE-SR8 share some features, but they also differ in a number of ways as discussed in the previous section.

The following table shows a clear picture of how they compare to each other.

 400GBASE-SR4.2400GBASE-SR8
AllianceIEEE 802.3cmIEEE 802.3cm (breakout: 802.3cd)
Max reach150m over OM5100m over OM4/OM5
Fibers8 fibers16 fibers (ribbon patch cord)
Wavelength2 wavelengths (850nm and 910nm)1 wavelength (850nm)
BiDi technologySupport/
Signal modulation formatPAM4 signalingPAM4 signaling
LaserVCSELVCSEL
Form factorQSFP-DD, OSFPQSFP-DD, OSFP

400GBASE-SR8 is technically simple but requires a ribbon patch cord with 16 fibers. It is usually built with 8 VCSEL lasers and doesn’t include any gearbox, so the overall cost of modules and fibers remains low. By contrast, 400GBASE-SR4.2 is technically more complex so the overall cost of related fibers or modules is higher, but it can support a longer reach.

In addition, 400GBASE-SR8 offers both flexibility and higher density. It supports fiber shuffling with 50G/100G/200G configurations and fanout at different I/O speeds for various applications. A 400G-SR8 QSFP-DD transceiver can be used as 400GBASE-SR8, 2x200GBASE-SR4, 4x100GBASE-SR2, or 8x50GBASE-SR.

400G SR4.2 & 400G SR8: Boosting Higher Speed Ethernet

As multimode fiber continues to evolve to serve growing demands for speed and capacity, both 400GBASE-SR4.2 and 400GBASE-SR8 help boost 400G Ethernet and scale up multimode fiber links too ensure the viability of optical solutions for various demanding applications.

The two IEEE 802.3cm standards provide a smooth evolution path for Ethernet, boosting cloud-based services and applications. Future advances point toward the ability to support even higher data rates as they are upgraded to the next level. The data center Industry will take advantage of the latest multimode fiber technology such as OM5 fiber, and use multiple wavelengths to transmit 100 Gb/s and 400 Gb/s over fibers over short reach of more than150 meters.

Beyond 2021-2022 timeframe, once an 800 Gb/s Ethernet standard is standardized, using more advanced technology with two-wavelength operation could create an 800 Gb/s, four-pair link. At the same time a single wavelength could support an 800 Gb/s eight-pair link. In this sense, 400GBASE-SR4.2 and 400GBASE-SR8 are setting the pace for a promising future.

Article Source: 400G Multimode Fiber: 400G SR4.2 vs 400G SR8

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Importance of FEC for 400G


The rapid adoption of 400G technologies has seen a spike in bandwidth demands and a low tolerance for errors and latency in data transmission. Data centers are now rethinking the design of data communication systems to expand the available bandwidth while improving transmission quality.

Meeting this goal can be quite challenging, considering that improving one aspect of data transmission consequently hurts another. However, one solution seems to stand out from the rest as far as enabling reliable, efficient, and high-quality data transmission is concerned. We’ve discussed more on Forward Error Correction (FEC) and 400G technology in the sections below, including the FEC considerations for 400Gbps Ethernet.

What Is FEC?

Forward Error Correction is an error rectification method used in digital signals to improve data reliability. The technique is used to detect and correct errors in data being transmitted without retransmitting the data.

FEC introduces redundant data and the error-correcting code before data transmission is done. The redundant bits/data are complex functions of the original information and are sent multiple times since an error can appear in any transmitted samples. The receiver then corrects errors without requesting retransmission of the data by acknowledging only parts of the data with no apparent errors.

FEC codes can also generate bit-error-rate signals used as feedback to fine-tune analog receiving electronics. The FEC code design determines the number of missing bits that can be corrected. Block codes and convolutional codes are the two FEC code categories that are widely used. Convolutional codes handle arbitrary-length data and use the Viterbi algorithm for decoding purposes. On the other hand, block codes handle fixed-size data packets, and partial code blocks are decoded in polynomial time to the code block length.

FEC

What Is 400G?

This is the next generation of cloud infrastructure widely used by high-traffic volume data centers, telecommunication service providers, and other large enterprises with relentless data transmission needs. The rapidly increasing network traffic has seen network carriers continually face bandwidth challenges. This exponential sprout in traffic is driven by the increased deployments of machine learning, cloud computing, artificial intelligence (AI), and IoT devices.

Compared to the previous 100G solution, 400G, also known as 400GbE or 400GB/s, is four times faster. This Terabit Ethernet transmits data at 400 billion bits per second, i.e., in optical wavelength; hence it’s finding application in high-speed, high-performance deployments.

The 400G technology also delivers the power, data density, and efficiency required for cutting-edge technologies such as virtual reality (VR), augmented reality (AR), 5G, and 4K video streaming. Besides consuming less power, the speeds also support scale-out and scale-up architectures by providing high density, low-cost-per-bit, and reliable throughput.

Why 400G Requires FEC

Several data centers are adopting 400 Gigabit Ethernet, thanks to the faster network speeds and expanded use cases that allow for new business opportunities. This 400GE data transmission standard uses the PAM4 technology, which offers twice the transmission speed of NRZ technology used for 100GE.

The increased speed and convenience of PAM4 also come with its own challenges. For instance, the PAM4 transmission speed is twice as fast as that of NRZ, but the signal levels are half that of 100G technology. This degrades the signal-to-noise ratio (SNR); hence 400G transmissions are more susceptible to distortion.

Therefore, forward error correction (FEC) is used to solve the waveform distortion challenge common with 400GE transmission. That said, the actual transmission rate of a 400G Ethernet link is 425Gbps, with the additional 25 bits used in establishing the FEC techniques. 400GE elements, such as DR4 and FR4 optics, have transmission errors, which FEC helps rectify.

FEC Considerations for 400Gbps Ethernet

With the 802.3bj standards, FEC-related latency is often targeted to be equal to or less than 100ns. Here, the receive time for FEC-frame takes approximately 50ns, with the rest time budget used for decoding. This FEC latency target is practical and achievable.

Using similar/same FEC code for the 400GbE transmission makes it possible to achieve lower latency. But when a higher coding gain FEC is required, e.g., at the PMD level, one can trade off FEC latency for the desired coding gain. It’s therefore recommended to keep a similar latency target (preferably 100ns) while pushing for a higher coding gain of FEC.

Given that PAM4 modulation is used, FEC’s target coding gain (CG) could be over 8dB. And since soft-decision FEC comes with excessive power consumption, it’s not often preferred for 400GE deployments. Similarly, conventional block codes with their limited latency need a higher overclocking ratio to achieve the target.

Assuming that a transcoding scheme similar to that used in 802.3bj is included, the overclocking ratio should be less than 10%. This helps minimize the line rate increase while ensuring sufficient coding gain with limited latency.

So under 100ns latency and less than 10% overclocking ratio, FEC codes with about 8.5dB coding gain are realizable for 400GE transmission. Similarly, you can employ M (i.e., M>1) independent encoders for M-interleaved block codes instead of using parallel encoders to achieve 400G throughput.

Conclusion

400GE transmission offers several benefits to data centers and large enterprises that rely on high-speed data transmission for efficient operation. And while this 400G technology is highly reliable, it introduces some transmission errors that can be solved effectively using forward error correction techniques. There are also some FEC considerations for 400G Ethernet, most of which rely on your unique data transmission and network needs.



Article Source: Importance of FEC for 400G

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FAQs About FS 400G Transceivers

FS 400G transceivers offer customers a wide variety of super high-density 400 Gigabit Ethernet connectivity options for data centers, enterprise networks, and service provider applications. Here is a list of FAQs about our new generation of 400G transceiver modules.

Q: What 400G transceivers are available from FS?

A: FS supports a full range of 400G optical transceivers in both OSFP and QSFP-DD form factors, 400G AOCs and DACs, and 400G breakout cables. The tables below summarize the 400G connectivity options FS supports.

CategoryProductMax Cable DistanceConnectorMediaPower Consumption
400G Transceivers400G QSFP-DD SR870m@OM3/100m@OM4MTP/MPO-16 (APC)MMF≤10W
400G QSFP-DD DR4500mMTP/MPO-12 (APC)SMF≤10W
400G QSFP-DD XDR42kmMTP/MPO-12SMF≤12W
400G QSFP-DD FR42kmDuplex LCSMF≤12W
400G QSFP-DD LR410kmDuplex LCSMF≤12W
400G QSFP-DD PLR410kmMTP/MPO-12SMF≤10W
400G QSFP-DD LR810kmDuplex LCSMF≤14W
400G QSFP-DD ER840kmDuplex LCSMF≤14W
400G OSFP SR8100mMTP/MPO-16MMF≤12W
400G OSFP DR4500mMTP/MPO-12 (APC)SMF≤10W
400G Cables400G QSFP-DD DAC/AOC100mQSFP-DD/≤11W
400G Breakout DAC/AOC30mQSFP-DD to 2x QSFP56, QSFP-DD to 4x QSFP56, QSFP-DD to 4x QSFP28, QSFP-DD to 8x SFP56/≤11W

Q: What are the benefits that FS 400G transceivers can offer?

A: FS 400G transceivers help cloud operators, service providers, and enterprises to achieve higher bandwidth at lower cost and power per gigabit. Key benefits of FS 400G transceivers include:

  • With both OSFP and QSFP-DD form factors to meet your diverse needs of ramping up to 400G transmission.
  • SiPh-based technology used on some FS 400G transceivers for lower power & cost and higher density.
  • Compliant with QSFP-DD MSA and IEEE 802.3bs, and tested in host devices for proven interoperability, superior performance, quality, and reliability.
  • Compatible with mainstream brands such as Cisco, Juniper, Arista, Dell, Mellanox, etc.
  • Simplify your network by reducing the number of optical fiber links, connectors and patch panels by a factor of 4.

Q: What are the application scenarios of FS 400G transceivers?

A: 400G QSFP-DD transceiver modules are the backbone of high-performance 400G networks. FS 400G transceivers can be used in various scenarios. Generally speaking, it depends on the connection distance you want to cover. For example, you can use 400G DAC and AOC cables for short-reach connections between ToR switch and server. For 2km to 10km data center interconnection connections, QSFP-DD FR4 or LR4 modules are better high-quality and economical choices.

Q: What quality certifications do you have for your 400G transceivers?

A: FS 400G transceivers accord with a range of certifications for optical transceivers including ISO 9001:2015, RoHS, REACH, CB, RCM, FCC, and Russian TR CU certificate (EAC Certificate). Rest assured that our products will meet essential quality and safety requirements.

Q: Are FS 400G transceivers compatible with Cisco or Juniper brands?

A: Many of our 400G transceiver modules are compatible with Cisco, Juniper, Arista, Dell, Mellanox, etc. You can always ask for a compatibility test before the purchase to check whether our transceiver is compatible with your devices. If you’re deploying a larger network or upgrading your current data center architecture, compatible transceiver modules may come in handy as they can be immediately installed without compatibility problems and fit right into your data center infrastructure.

Q: Can I plug FS OSFP module into a 400G QSFP-DD port, or FS QSFP-DD module into an OSFP port?

A: No. OSFP and QSFP-DD are two physically distinct form factors. If you have an OSFP system, then FS 400G OSFP modules must be used. If you have a QSFP-DD system, then FS 400G QSFP-DD modules must be used.

Q: Can FS 100G QSFP module be plugged into a 400G QSFP-DD port?

A: Yes. A 40/100GQSFP transceiver module can be inserted into a QSFP-DD port as QSFP-DD is backward compatible with QSFP, QSFP+, and QSFP28 transceiver modules. When using a QSFP module in a 400G QSFP-DD port, the QSFP-DD port must be configured for a data rate of 100G.

Q: What should I do if I don’t know which transceiver module is the right one for me?

A: Our dedicated customer support offers 24/7 technical assistance. If you have any questions about our transceiver modules, such as how to select the right 400G optical transceiver for your switches, how to choose between different form factors, what to do when typical technical glitches occur, or how to place an order, don’t hesitate to contact our tech support.

Q: Can I return the product or get a refund?

A: FS wants you to be thrilled with our 400G transceiver modules. However, if you need to return an item or ask to get a refund, we’re here to help. For all 400G transceiver modules, DAC & AOC cables, and breakout cables, you have 30 calendar days to return an item from the date you received it, which means the request must be submitted within the return/exchange window. Refunds will be processed after FS receives and inspects the returned items.

Q: How long is the warranty period for FS 400G transceivers?

A: We offer you a warranty period of five years for the purchase of 400G transceiver modules, DAC & AOC cables, and breakout cables. The warranty covers only defects arising under normal use and does not include malfunctions or failures resulting from misuse, abuse, neglect, alteration, problems with electrical power, usage not in accordance with product instructions, acts of nature, or improper installation or improper operation or repairs made by anyone other than FS or an FS authorized service provider. Please check FS Products Warranty for detailed info.

If you have any questions about FS 400G transceiver modules, you can always Contact Us for assistance.

Article Source

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

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Basics about 400G DAC and 400G AOC

Data centers, enterprises, and high-performance computing environments require flexible and well-defined 50G, 100G, 200G, and 400G direct attach cables for interconnection within a rack or between adjacent racks. With the development of 400G technology, 400G direct attach cables for short-distance DCI (Data Center Interconnect) have been mass-produced and put into market, which includes 400G DAC and 400G AOC.

Main Types of 400G DAC & AOC in the Market

Either 400G DAC or 400G AOC comes with two main form factors: QSFP-DD and OSFP, both of which can carry 8x50Gb/s PAM4 electrical lanes. Besides, there are also 400G breakout DAC/AOCs, with one 400G connector at one end, and several same connectors whose total rate is 400G at the other end. The table below shows the main types of 400G DAC /AOC and the 400G breakout DAC/AOCs in the market.

CatagoryNameProduct DescriptionReachApplication
400G QSFP-DD DACQSFP-DD to QSFP-DD DACwith each 400G QSFP-DD using 8x 50G PAM4 electrical lanesno more than 3m400G network direct connection
400G QSFP-DD Breakout DACQSFP-DD to 2x 200G QSFP56 DACwith each 200G QSFP56 using 4x 50G PAM4 electrical lanesno more than 3m400G to 200G network connection
QSFP-DD to 4x 100G QSFPs DACwith each 100G QSFPs using 2x 50G PAM4 electrical lanesno more than 3m400G to 100G network connection
QSFP-DD to 8x 50G SFP56 DACwith each 50G SFP56 using 1x 50G PAM4 electrical laneno more than 3m400G to 50G network connection
400G QSFP-DD AOCQSFP-DD to QSFP-DD AOCwith each 400G QSFP-DD using 8x 50G PAM4 electrical lanes70m (OM3) or 100m (OM4)400G network direct connection
400G QSFP-DD Breakout AOCQSFP-DD to 2x 200G QSFP56 AOCwith each 200G QSFP56 using 4X 50G PAM4 electrical lane70m (OM3) or 100m (OM4)400G to 200G network connection
QSFP-DD to 8x 50G SFP56 AOCwith each 50G SFP56 using 1x 50G PAM4 electrical lane70m (OM3) or 100m (OM4)400G to 50G network connection
400G OSFP DACOSFP to OSFP DACwith each 400G OSFP using 8x 50G PAM4 electrical lanesno more than 3m400G network direct connection
400G OSFP Breakout DACOSFP to 2x 200G QSFP56 DACwith each 200G QSFP56 using 4x 50G PAM4 electrical lanesno more than 3m400G to 200G network connection
OSFP to 4x100G QSFPs DACwith each 100G QSFPs using 2x 50G PAM4 electrical lanesno more than 3m400G to 100G network connection
OSFP to 8x 50G SFP56 DACwith each 50G SFP56 using 1x 50G PAM4 electrical laneno more than 3m400G to 50G network connection
400G OSFP AOCOSFP to OSFP AOCwith each 400G OSFP using 8x 50G PAM4 electrical lanes70m (OM3) or 100m (OM4)400G network direct connection

Differences Between 400G DAC and 400G AOC

According to the table, we know that the main differences between 400G DAC and 400G AOC are transmission distance and the available types on the market. At present, 400G DAC can provide more breakout cables and better satisfy your different connection requirements. Apart from that, 400G DAC and AOC differ from each other in the following aspects.

  • Weight and volume – With fiber optic cable as transmission media, 400G AOC has about half the volume and only a quarter the weight of 400G copper DAC. Also, its cable bending radius is smaller than 400G DAC.
  • Interference-resistance – Since 400G AOC with fiber optic cable doesn’t conduct electrical currents, it is resistant to interference from electromagnetic, lightning, or radio signals during data transmission. While 400G DAC with copper cable is vulnerable to power lines, lightning, and signal-scrambling.
  • Price – On today’s 400GbE cable market, the price of the 400G AOC is often higher than that of 400G DAC, of course, with the same level. If both of them can meet your needs, you can choose a 400G DAC to save costs.

Further Consideration about 400G DAC and 400G AOC

Both 400G DAC and AOC are cost-effective solutions for short-distance transmission. When it comes to the transmission over 100m, 400G optical transceivers combined with the matched fiber optic cables are a suitable solution. In today’s market, 400G QSFP-DD/OSFP transceivers are continuously being pushed to the market and gradually realize mass production. So, what are 400G QSFP-DD/OSFP transceiver types and what fiber optic cables could be used with these 400G optical modules? Continue reading to find the answers in the two articles: 400G OSFP Transceiver Types Overview400G QSFP-DD Transceiver Types Overview.

FAQ about 400G DAC/AOC

Q: Why does 400G DAC/AOC adopt PAM4 modulation?

A: PAM4 is a more efficient modulation technology that can effectively improve the bandwidth utilization efficiency. With same Baud rate, PAM4 signal can transmit twice faster than the traditional NRZ signal. Also, the transmission costs are greatly reduced.

Q: What’s the key technology of 400G DAC/AOC?

A: The core technologies of 400G DAC/AOC are PAM4 and DSP. Since PAM4 is more sensitive to noise than NRZ especially in 400G AOC, DSP is introduced to make up for the disadvantage of PAM4. As a high-speed digital processing chip, DSP not only owns the function of recovering signal provided by the traditional CDR but also can make dispersion compensation and remove noise, nonlinear disturbance as well as other interferences.

FS 400G DAC Cables

Article Source

https://community.fs.com/blog/400g-direct-attach-cables-dac-and-aoc-overview.html

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ROADM for 400G WDM Transmission

As global optical networks advance, there is an increasing necessity for new technologies such as 400G that meet the demands of network operators. Video streaming, surging data volumes, 5G network, remote working, and ever-growing business necessities create extreme bandwidth demands.

Network operators and data centers are also embracing WDM transmission to boost data transfer speed, increase bandwidth and enhance a better user experience. And to solve some of the common 400G WDM transmission problems, such as reduced transmission reach, ROADMs are being deployed. Below, we have discussed more about ROADM for 400G WDM transmission.

Reconfigurable Optical Add-drop Multiplexer (ROADM) Technology

ROADM is a device with access to all wavelengths on a fiber line. Introduced in the early 2000s, ROADM allows for remote configuration/reconfiguration of A-Z lightpaths. Its networking standard makes it possible to block, add, redirect or pass visible light beams and modulated infrared (IR) in the fiber-optic network depending on the particular wavelength.

ROADMs are employed in systems that utilize wavelength division multiplexing (WDM). It also supports more than two directions at sites for optical mesh-based networking. Unlike its predecessor, the OADM, ROADM can adjust the add/drop vs. pass-through configuration whenever traffic patterns change.

As a result, the operations are simplified by automating the connections through an intermediate site. This implies that it’s unnecessary to deploy technicians to perform manual patches in response to a new wavelength or alter a wavelength’s path. The results are optimized network traffic where bandwidth demands are met without incurring extra costs.

ROADM

Overview of Open ROADM

Open ROADM is a 400G pluggable solution that champions cross-vendor interoperability for optical equipment, including ROADMs, transponders, and pluggable optics. This solution defines some optical interoperability requirements for ROADM and comprises hardware devices that manage and routes traffic over the fiber optic lines.

Initially, Open ROADM was designed to address the rise in data traffic on wireless networks experienced between 2007 and 2015. The major components of Open ROADM – ROADM switch, pluggable optics, and transponder – are controllable via an open standards-based API accessible through an SDN Controller.

One of the main objectives of Open ROADM is to ensure network operators and vendors devise a universal approach to designing networks that are flexible, scalable, and cost-effective. It also offers a standard model to streamline the management of multi-vendor optical network infrastructure.

400G and WDM Transmission

WDM transmission is a multiplexing technique of several optical carrier signals through a single optical fiber channel by varying the wavelength of the laser lights. This technology allows different data streams to travel in both directions over a fiber network, increasing bandwidth and reducing the number of fibers used in the primary network or transmission line.

With 400G technology seeing widespread adoption in various industries, there’s a need for optical fiber networking systems to adapt and support the increasing data speeds and capacity. WDM transmission technique offers this convenience and is considered a technology of choice for transmitting larger amounts of data across networks/sites. WDM-based networks can also hold various data traffic at different speeds over an optical channel, allowing for increased flexibility.

400G WDM still faces a number of challenges. For instance, the high symbol rate stresses the DAC/ADC in terms of bandwidth, while the high-order quadrature amplitude modulation (QAM) stresses the DAC/ADC in terms of its ENOB (effective number of bits.)

As far as transmission performance is concerned, the high-order QAM requires more optical signal-to-noise ratio (OSNR) at the receiver side, which reduces the transmission reach. Additionally, it’s more sensitive to the accumulation of linear and non-linear phase noise. Most of these constraints can be solved with the use of ROADM architectures. We’ve discussed more below.

WDM Transmission

Open ROADM MSA and the ROADM Architecture for 400G WDM

The Open ROADM MSA defines some interoperability specifications for ROADM switches, pluggable optics, and transponders. Most ROADMs in the market are proprietary devices built by specific suppliers making interoperability a bit challenging. The Open ROADM MSA, therefore, seeks to provide the technical foundation to deploy networks with increased flexibility.

In other words, Open ROADM aims at disaggregating the data network by allowing for the coexistence of multiple transponders and ROADM vendors with a few restrictions. This can be quite helpful for 400G WDM systems, especially when lead-time and inventory issues arise, as the ability to mix & match can help eliminate delays.

By leveraging WDM for fiber gain as well as optical line systems with ROADMs, network operators can design virtual fiber paths between two points over some complex fiber topologies. That is, ROADMs introduce a logical transport underlay of single-hop router connections that can be optimized to suit the IP traffic topology. These aspects play a critical role in enhancing 400G adoption that offers the much-needed capacity-reach, flexibility, and efficiency for network operators.

That said, ROADMs have evolved over the years to support flexile-grid WSS technology. One of the basic ROADM architectures uses fixed filters for add/drop, while the other architectures offer flexibility in wavelength assignment/color or the option to freely route wavelengths in any direction with little to no restriction. This means you can implement multi-degree networking with multiple fiber paths for every node connecting to different sites. The benefit is that you can move traffic along another path if one fiber path isn’t working.

Conclusion

As data centers and network operators work on minimizing overall IP-optical network cost, there’s a push to implement robust, flexible, and optimized IP topologies. So by utilizing 400GbE client interfaces, ROADMs for 400G can satisfy the ever-growing volume requirements of DCI and cloud operators. Similarly, deploying pluggable modules and tapping into the WDM transmission technique increases network capacity and significantly reduces power consumption while simplifying maintenance and support.

Article Source: ROADM for 400G WDM Transmission
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PAM4 in 400G Ethernet application and solutions

400G PAM4 (4 Pulse Amplitude Modulation) is the modulation technology that fits for high-speed signal interconnection in the next-generation data center, paving the way to 400G Ethernet in data centers. What is 400G PAM4? Why is it chosen to be applied to 400G Ethernet? Find answers here.

What Is PAM4 for 400G Ethernet?

Pulse Amplitude Modulation 4-level (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). By transmitting two bits in one symbol slot, PAM4 halves the signal bandwidth. Therefore, it is feasible to increase bandwidth by using advanced modulation PAM4 technology to increase the data rate without having to configure the data center with more fibers. 400 Gbps Ethernet can be realized with four lanes of PAM4 (8× 50 Gbps). This effectively doubles a network’s data rate, enabling 400G PAM4 for short-haul and long-haul transmission.

Why Does 400G Ethernet Need to Use PAM4 Technology?

In terms of supporting 400G Ethernet speed, the transmission rate of NRZ 25Gbps single channel has reached its limit, which cannot be adapted to the development of current high-density data centers. When discussing the 400GE IEEE 802.3bs standard, it was proposed to replace NRZ with PAM4 technology. So why is 400G PAM4 technology a viable alternative to NRZ?

Benefits of 400G PAM4

PAM4 modulation replaces 400G Ethernet using 16×25G baud rate NRZ and provides a path from 100G Ethernet using 4×25G baud rate to 400G Ethernet through 8×25G baud rate architecture. It is called 400G Ethernet The link adopts the 8×50G bit rate solution, reducing not only the fiber cost but also the link loss. For hyper-scale data centers, it’s time for them to transition from the previous 100G or Gigabit networks to 400G PAM4 Ethernet for faster transmission efficiency..

Compared to the NRZ signal, PAM4 has some better advantages. PAM4 carries 2 bits per symbol and transmits twice the NRZ information per symbol period. Hence, PAM4 doubles the bit rate for a given baud, thereby bringing higher efficiency to 400G transmission with greatly reduced signal loss. This key benefit of PAM4 allows existing channels and interconnects to be used at higher bit rates without doubling the baud rate and increasing channel loss..

PAM4 vs NRZ

Some information about the specific differences between PAM4 and NRZ. NRZ signaling uses two signal levels in which positive voltage defines bit 1 and the zero voltage defines bit 0. 1 bit signal is transmitted during a clock cycle.

PAM4 vs NRZ

Figure: PAM4 vs NRZ

Double Bit Rate – PAM4 doubles the bit rate for a given baud rate over NRZ. Thus, a 28 Gbaud PAM4 signal can deliver the same bit rate as a 56 Gbaud NRZ signal.

Less Signal Loss – PAM4 should let you develop 56 Gbps data lanes with less signal loss than would occur by simply doubling the NRZ (sometimes called NRZ-PAM2) bit rate. Exotic PCB materials can compensate for the deficiencies, but at a cost few are willing to pay.

400G PAM4 Transceivers: Multi-mode vs Singlemode

The 400G QSFP-DD transceivers modulation method uses PAM4 technology, including multi-mode and single-mode. In addition, the electrical port side of the 400G optical module supports 8x50G PAM4 modulation, and the optical port side supports both 8x50G PAM4 and 4x100G PAM4 modulation.

Both 400G SR8 and 400G SR4.2 multimode optical modules support 8x50G PAM4. 400G SR8 optical modules can use MPO-16 connectors or MPO-24 connectors to connect 8 pairs of fibers. The 400G SR4.2 modules use MPO-12 connectors, and the wavelengths are bidirectional and multiplexed.

According to the above mentioned, in the single-mode 400G optical module, the electrical port side is modulated with 4x100G PAM4, and a group of the optical port side is modulated with 8x50G PAM4. There are three common 8x50G PAM4 400G optical modules: FR8, LR8, and 2xFR4. 400G FR8 and 400G LR8 are the earliest available 400G single-mode interfaces, 8 wavelengths are multiplexed into one fiber, and duplex LC light is used at the same time. interface. The 2xFR4 400G optical module uses 8 lasers but is divided into two groups of 4 wavelengths according to the 200G FR4 standard.

400G optical modules modulated by 4x100G PAM4 are the focus of the current market, including 400G DR4, 400G FR4, and LR4, and their line-side uses four channels of 100G PAM4. In the 400G DR4 optical module, the DSP converts the 8x50G PAM4 electrical signal into 4x100G PAM4 and then transmits it to the optical engine.

Transceiver Solution Based on 400G PAM4

PAM4 is a relatively low-cost solution for 400GbE and data centers that has been adopted by the transceiver industry, enabling high-speed data rates, moving toward 400G and beyond. FS 400G transceivers apply 4×100G PAM4 or 8×50G PAM4 technology, which have been standardized by the IEEE working group, including 400GBASE-SR8, DR4, LR8, ER8, XDR4, FR4, and LR4. The FS 400G transceivers use a pluggable double-density design to support transmission requirements of different distances. At the same time, they can perform signal conversion through PAM4, and use multiplexing technology to convert transmission channels to achieve reasonable distribution of data center fiber resources.

StandardTransceiver TypesLink DistanceMedia TypeLanesPower Consumption
IEEE P802.3cm400GBASE-SR8100mMMF8× 50G PAM4<10W
IEEE 802.3bs400GBASE-DR4500mSMF4× 100G PAM4<10W
400GBASE-LR810kmSMF8× 50G PAM4<14W
IEEE P802.3cn400GBASE-ER840kmSMF8× 50G PAM4<14W
100G Lambda MSA400GBASE-XDR42kmSMF8× 50G PAM4<12W
400GBASE-FR42kmSMF4× 100G PAM4<12W
400GBASE-LR410kmSMF4× 100G PAM4<12W

Conclusion

As the market moves to PAM4-based modulation, more and more chip makers and transceiver vendors are manufacturing new 400G products using PAM4, transferring 400G PAM4 from theory to practice. PAM4 400G based on 50G PAM4 or 100G PAM4 will certainly become the basic rate of the next-generation Ethernet and stand out with its high performance and potential.

Article Source

https://community.fs.com/blog/pam4-for-400g-ethernet-applications.html

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How Many 400G Transceiver Types Are in the Market?

With the tremendous requirement for high bandwidth in 5G, loT and cloud data center, the focus of 400G Ethernet has been lasting for a couple of years. Vendors such as Cisco, Arista, and juniper are developing and testing technologies for 400G Ethernet networks. As the key hardware devices for interconnecting optical networks, there is no dispute that 400G transceiver will become the mainstream of the industry. Still curious about 400G transceivers? This paper will give you a comprehensive introduction to the different 400G transceiver types of different characteristics including applications, interface standards, and form factors.

Transceiver Application

According to the transceiver application, optical modules can be classified into two categories: client-side transceivers and line-side transceivers.

400G Ethernet Transceivers for Client Side Transmission

Client-side transceivers are used to interconnect between the metro networks and the optical backbone. The term “client side” refers to relatively short distances compared with the line side, generally from 50m to 10km and with only one transceiver connected to fiber thus no coherent optics is needed. There are various transceiver interfaces that have been standardized by IEEE and MSA. Most importantly, it has an agreed and standardized interface that is used for the network connection. PAM4 has been chosen by IEEE 802.3bs for 400GE client side transmission.

400G Coherent Transceivers for Line Side Transmission

Different from client side, line side reaches transmission distances of 80km or even longer using DWDM. Coherent technology is expected to implement 400G line side transmission. OIF has been working on standardizing the 400G coherent DWDM interface for DCI and other metro/access applications. The signal processing of coherent transport is much greater than that of short reach PAM4 data center transmission, which requires more DSPs and power than in client side transmission.

Interface Standard

The transceiver interfaces are defined by the interface standards. The following chart lists the common 400G Ethernet standards and the corresponding interfaces.

Interface standardInterfaceLink DistanceMedia TypeOptical Architecture
IEEE 802.3bs400GBASE-SR16100mMMF16× 25G NRZ 850nm
400GBASE-DR4500mSMF4× 100G PAM4 1300nm
400GBASE-FR82kmSMF8× 50G PAM4 WDM
400GBASE-LR810kmSMF8× 50G PAM4 WDM
IEEE P802.3cm400GBASE-SR8100mMMF8× 50G PAM4 850nm
400GBASE-SR4.2100mMMF8× 50G PAM4 BiDi 850/910nm
IEEE P802.3cn400GBASE-ER840kmSMF8× 50G PAM4 WDM
IEEE P802.3ct400GBASE-ZR80kmSMFCoherent DWDM
100G Lambda MSA400GBASE-FR42kmSMF4× 100G PAM4 CWDM
400GBASE-LR410kmSMF4× 100G PAM4 CWDM
CWDM8 MSA400G-CWDM8-22m to 2kmSMF8× 50G CWDM
400G-CWDM8-102m to 10kmSMF8× 50G CWDM

Note: 400GBASE-SR16 has not been released by any transceiver vendors. As 400GBASE-SR16 interface requires a high fiber count (32 fibers per duplex link), this standard is not expected to enter the 400G transceiver market.

400G Transceiver Form Factor

There are several mainstream 400G form factors,400G QSFP-DD, OSFP, CFP8, COBO, etc., some of which have been put in the market and some are still as a design.

  • CFP8 is the first generation 400G transceiver, with a relatively large physical size, offering the lowest port density.
  • COBO is named for Consortium for On-Board Optics, installed internally to the line-card equipment in a controlled environment, thus lacking flexibility.
  • OSFP stands for Octal Small Form Factor Pluggable, which is a new kind of pluggable form factor. There are some companies that have already sold 400G OSFP transceivers on the website.
  • 400G QSFP-DD transceivers are now one of the most popular optical modules in the market, which have been launched and manufactured by Finisar, Innolight, FS.COM, etc.QSFP-DD vs OSFP vs CFP8.jpg

The table below includes detailed comparisons of size, compatibility, power, etc. for the three main form factors: OSFP, QSFP-DD and CFP8.

OSFPQSFP-DDCFP8
Application ScenarioData center & telecomData centerTelecom
Size22.58mm× 107.8mm× 13mm18.35mm× 89.4mm× 8.5mm40mm× 102mm× 9.5mm
Max Power Consumption15W12W24W
Backward Compatibility with QSFP28Through adapterYesNo
Electrical signaling (Gbps)8× 50G8× 50G8× 50G
Switch Port Density (1RU)363616
Media TypeMMF & SMFMMF & SMFMMF & SMF
Hot PluggableYesYesYes
Thermal ManagementDirectIndirectIndirect
Support 800GYesNoNo

Among these three transceiver form factors, it is obvious CFP8 lacks density, unlike the other two 400G transceivers. OSFP modules have been designed with 800G in mind. The QSFP-DD form factor has the main advantages of its high density, small size, and back forward compatibility that it supports QSFP28 enabling easier migration to 400G Ethernet, which addresses the industry need for high speed and high-density networking. Therefore it is expected that QSFP-DD form factor will become the most appropriate form factor for the 400G Ethernet applications.

Summary

Apart from the above categories of 400G transceivers, fiber mode, wavelength, etc. are also the common characteristics that are used in optical transceiver classification, which are not further explained. The demand for high-speed data transmission is rocketing. As the transceiver market is pushed to shift, we can expect the 400G Ethernet deployment in the next-generation data centers and the popularity of 400G optical transceivers in the near future. Though both opportunities and challenges in the 400G transceiver test exist in the research stage, 400G Ethernet is still an inevitable trend.

Article Source

https://community.fs.com/blog/400g-ethernet-400g-transceiver.html

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400G ZR vs. Open ROADM vs. ZR+


As global optical networks evolve, there’s an increasing need to innovate new solutions that meet the requirements of network operators. Some of these requirements include the push to maximize fiber utilization while reducing the cost of data transmission. Over the last decade, coherent optical transmission has played a critical role in meeting these requirements, and it’s expected to progressively improve for the next stages of tech and network evolution.

Today, we have coherent pluggable solutions supporting data rates from 100G to 400G. These performance-optimized systems are designed for small spaces and are low power, making them highly attractive to data center operators. We’ve discussed the 400G ZR, Open ROADM, and ZR+ optical networking standards below.

Understanding 400G ZR vs. Open ROADM vs. ZR+

Depending on the network setups and the unique data transmission requirements, data centers can choose to deploy any of the coherent pluggable solutions. We’ve highlighted key facts about these solutions below, from definitions to differences and applications.

What Is 400G ZR?

400G ZR defines a classic, economical, and interoperable standard for transferring 400 Gigabit Ethernet over a single optical wavelength using DWDM (dense wavelength division multiplexing) and higher-order modulation such as 16 QAM. The Optical Interoperability Forum (OIF) developed this low-cost standard for data transmission as one of the first standards to define an interoperable 400G interface.

400G ZR leverages an ultra-modern coherent optical technology and supports high-capacity point-to-point data transport over DCI links between 80 and 120km. The performance of 400ZR modules is also limited to ensure it’s cost-effective with a small physical size. This helps ensure that the power consumption fits within smaller modules such as the Quad Small Form-Factor Pluggable Double-Density (QSFP-DD) and Octal-Small Form-Factor Pluggable (OSFP). The 400G ZR enables the use of inexpensive yet modest performance components within the modules.

400G ZR

What Is Open ROADM?

This is one of the 400G pluggable solutions that define interoperability specifications for Reconfigurable Optical Add/Drop Multiplexers (ROADM). The latter comprises hardware devices that manage and route data traffic transported over high-capacity fiber-optic lines. Open ROADM was first designed to combat the surge in traffic on the wireless network experienced between the years 2007 and 2015.

The key components of Open ROADM include ROADM switch, transponders, and pluggable optics – all controllable via open standards-based API accessed via an SDN Controller utilizing the NETCONF protocol. Launched in 2016, the Open ROADM initiative’s main objective was to bring together multiple vendors and network operators so they could devise an agreed approach to design networks that are scalable, cost-effective, and flexible.

This multi-source agreement (MSA) aims to shift from a traditionally closed ROADM optical transport network toward a disaggregated open transport network while allowing for centralized software control. Some of the ways to disaggregate ROADM systems include hardware disaggregation (e.g., defining a common shelf) and functional disaggregation (less about hardware, more about function).

The Open ROADM MSA went for the functional disaggregation first because of the complexity of common shelves. The team intended to focus on simplicity, concentrating on lower-performance metro systems at the time of its first release. Open ROADM handles 100-400GbE and 100-400G OTN client traffic within a typical deployment paradigm of 500km.

Open ROADM

What Is ZR+?

The ZR+ represents a series of coherent pluggable solutions holding line capacities up to 400 Gb/s and stretching well past the 120km specification for 400ZR. OpenZR+ was designed to maintain the classic Ethernet-only host interface of 400ZR while adding support to aid features such as the extended point-to-point reach of up to around 500km and the inclusion of support for OTN Ethernet, etc.

The recently issued MSA provides interoperable 100G, 200G, 300G & 400G line rates over regional, metro, and long-haul distances, utilizing OpenFEC forward error correction and 100-400G optical line specifications. There’s also a broad range of coverage for ZR+ pluggable, and these products can be deployed across routers, switches, and optical transport equipment.

ZR+

400G ZR, Open ROADM, and ZR+ Differences

Target Application

400ZR and OpenZR+ were designed to satisfy the growing volume requirements of DCI and cloud operators using 100GbE/400GbE client interfaces, while OpenROADM provides a good alternative for carriers that require transporting OTN client signals (OTU4).

In other words, the 400ZR efforts concentrate on one modulation type and line rate (400G) for metro point-to-point applications. On the other hand, the OpenZR+ and Open ROADM groups concentrate on high-efficiency optical specifications capable of adjustable 100G-400G line rates and lengthier optical reaches.

400G Reach: Deployment Paradigm

400ZR modules support high-capacity data transport over DCI links of up to 80 to 120km. On the other hand, OpenZR+ and OpenROADM, under perfect network presumption, can transmit the network for up to 480 km in 400G mode.

Power Targets

The power consumption targets of these coherent pluggable also vary. For instance, the 400zr has a target power consumption of 15W, while Open ROADM and ZR+ have power consumption targets of not more than 25W.

Applications for 400G ZR, Open ROADM and ZR+

Each of these coherent pluggable solutions finds use cases in various settings. Below is a quick summary of the three data transfer standards and their major applications.

  • 400G ZR – frequently used for point-to-point DCI (up to 80km), simplifying the task of interconnecting data centers.
  • Open ROADM – This architecture can be deployed using different vendors, provided they exist in the same network. It gives the option to use transponders from various vendors at the end of each circuit.
  • ZR+ – It provides a comprehensive, open, and flexible coherent solution in a relatively smaller form factor pluggable module. This standard addresses hyperscale data center applications for high-intensive edge and regional interconnects.

A Look into the Future

As digital transformation takes shape across industries, there’s an increasing demand for scalable solutions and architectures for transmitting and accessing data. The industry is also moving towards real-world deployments of 400G networks, and the three coherent pluggable solutions above are seeing wider adoption.

400ZR and the OpenZR+ specifications were developed to meet the network demands of DCI and cloud operators using 100 and 400GbE interfaces. On the other hand, Open ROADM offers a better alternative for carriers that want to transport OTN client signals. Currently, Open ZR+ and Open ROADM provide more benefits to data center operators than 400G ZR, and technology is just getting better. Moving into the future, optical networking standards will continue to improve both in design and performance.

Article Source: 400G ZR vs. Open ROADM vs. ZR+
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