Category Archives: Network Solutions

Differences Between QSFP-DD and QSFP+ / QSFP28 / QSFP56 / OSFP / CFP8 / COBO

QSFP-DD, as the smallest form factor for 400G transceivers, offers industry’s highest bandwidth density while leveraging the backward compatibility to lower-speed QSFP pluggable modules and cables, making it popular among the fiber optic manufacturers. As the newest hot type of optical transceivers in 400G high-speed applications, QSFP-DD is often compared with other modules such as QSFP56, OSFP, CFP8, and COBO. So what are the differences among these optical modules? This post will illustrate them thoroughly.

QSFP-DD Wiki

QSFP-DD (also called QSFP56-DD) stands for Quad Small Form Factor Pluggable Double Density, which is fully compliant with IEEE802.3bs and QSFP-DD MSA standards. The “double density” means the doubling of the number of high-speed electrical interfaces that the module supports compared with a standard QSFP28 module. The data rate of each channel can reach 25Gb/s through NRZ modulation technology, realizing 200G network transmission. Also, the data rate of each channel can reach 50Gb/s by the PAM4 modulation technology, achieving 400G network transmission, which is suitable for high-performance computing data center and cloud network. For more information about PAM4 modulation technology, please visit: PAM4: Learn 400G Ethernet From Here.

The advantages of QSFP-DD form factor are as follows:

Backward compatibility: allowing the QSFP-DD to support existing QSFP modules (such as QSFP+, QSFP28, QSFP56, etc.) and provide flexibility for end-users and system designers.
Adopting the 2×1 stacked integrated cage/connector to support the one-high cage connector and two-high stack cage connector system.
SMT connector and 1xN cage design: this kind of design can enable thermal support of at least 12W per module. The higher thermal reduces the requirement for heat dissipation capabilities of transceivers, thus reducing some unnecessary costs.
ASIC design: supporting multiple interface rates and fully backward compatible with QSFP+ and QSFP28 modules, thus reducing port and equipment deployment costs.

QSFP-DD vs QSFP+/QSFP28/QSFP56

QSFP-DD, QSFP+, QSFP28 and QSFP56 belong to the QSFP form factor, but what are the differences among them? The differences are explained in the following descriptions.

Structure

In terms of the appearance, the width, length and thickness of the QSFP-DD are the same as QSFP+, QSFP28 and QSFP56. But the QSFP-DD module is equipped with an 8-lane electrical interface rather than a 4-lane like other QSFP modules and the ASIC ports of QSFP-DD are doubled to support existing interfaces such as CAUI-4. Therefore, the mechanical interface of QSFP-DD on the host board is slightly deeper than that of the other QSFP system transceivers to accommodate the extra row of contacts.

Bandwidth & Application

The QSFP-DD modules can support 400Gbps while QSFP+/QSFP28/QSFP56 can only reach 40Gbps/100Gbps/200Gbps respectively. Therefore, QSFP-DD connectors are used in 400G optical modules, DACs and AOCs, and applied for the 400G data center interconnections. And QSFP+/QSFP28/QSFP56 modules and DAC/AOC are used for 40G/100G/200G networks. interconnection.

Backward Compatibility

As mentioned above, the QSFP-DD can be backward compatible with the previous QSFP system transceiver modules. In other words, based on the previous form factor, the QSFP-DD has been technically upgraded to support increased bandwidth. And its backward compatibility can avoid existing equipment replacement on the scale and effectively reduce the network upgrade cost.

Form Factor	QSFP-DD	QSFP56	QSFP28	QSFP+
Released Year	2016	2018	2016	2010
Number of Electrical Interface Lanes	8	4	4	4
Single Channel Rate	25Gbps/50Gbps	50Gbps	25Gbps	10Gbps
Modulation Technology	NRZ/PAM4	PAM4	NRZ	NRZ
Backward Compatibility	QSFP+/QSFP28/QSFP56	QSFP+/QSFP28	QSFP+	/

QSFP-DD vs OSFP/CFP8/COBO

QSFP-DD (QSFP56-DD) and OSFP/CFP8/COBO are the form factors of 400G optics on the market, the differences of them are listed below:

QSFP-DD vs OSFP

OSFP is a new pluggable form factor with eight high speed electrical lanes that will initially support 400Gb/s (8x50G) or reach up to 800Gb/s. The width, length and thickness of QSFP-DD are 18.35mm, 89.4mm and 8.5mm, while those of OSFP are 22.58mm, 107.8mm and 13.0mm. It is obvious that the OSFP form factor is slightly wider and deeper than the QSFP-DD, but it still supports 36 OSFP ports per 1U front panel, enabling 14.4Tb/s per 1U.

Generally, the power consumption of QSFP-DD is 7-12W, while the OSFP can reach 12-15W. The lower the power consumption, the better the performance of the transceiver. Unlike the QSFP-DD, OSFP can’t be backward compatible with QSFP+/QSFP28 since it has a larger size than that of QSFP+/QSFP28.

QSFP-DD vs CFP8

Featuring a 41.5mm*107.5mm*9.5mm form factor, the CFP8 module delivers four times more bandwidth than existing 100G solutions. Its electrical interface has been generally specified to allow for 16×25 Gb/s and 8×50 Gb/s mode. Since the size of CFP8 is almost three times larger than that of QSFP-DD, the power consumption of CFP8 is much higher than QSFP-DD. Meanwhile, the CFP8 can’t be used on QSFP+/QSFP28 ports. The maximum bandwidth of CFP8 and QSFP-DD is 400Gb/s, but CFP8 only supports in the form of 16x25G or 8x50G while QSFP-DD also supports both 200Gb/s (8x25G).

QSFP-DD vs COBO

COBO stands for Consortium for On-Board Optics, it can be installed internally to the line-card equipment in a controlled environment, which lacks flexibility. And it doesn’t support hot-pluggable, so it is more difficult for COBO modules to maintain than QSFP-DD. Additionally, the COBO form factor has two electrical interfaces——one eight lane and the other sixteen lane to meet both 1x400G and 2x400G transmission requirements.

The following chart shows the market maturity of the QSFP-DD, OSFP, CFP8 and COBO form factors. The larger the numbers, the higher the market maturity of these form factors.

Performance	CFP8	OSFP	QSFP-DD	COBO
Volume	1	2	3	4
Power Consumption	3	2	1	4
Cost	1	3	4	2
Maturity	4	3	2	1
Compatibility	3	2	4	1
Difficulty for Operation & Maintenance	2	3	4	1
Overall Ratings	14	15	18	13

We can see from the table that the overall rating of QSFP-DD and OSFP form factors are higher than other form factors. So the QSFP-DD and OSFP are more popular with fiber optic manufacturers. While the former is suitable for data center applications and the latter often applied for telecommunications applications. For more types of 400G transceivers, please refer to How Many 400G Transceiver Types Are in the Market? for more detailed information.

Will QSFP-DD Be Popular in 800G Ethernet?

The QSFP-DD (QSFP56-DD) is more suitable for data center applications than OSFP. With the concentration of east-west traffic in the data center and the increasing pressure on the internal bandwidth of the data center, the time gap between the application of high-speed optical modules in the telecom market and the data center market is gradually shortening. The 400G optics will be applied widely. That is, QSFP-DD will benefit from the 400G Ethernet and ushered in a good development prospect.

As 400G becomes commercially available on a large scale, single-wave 100G technology is set to mature, laying the groundwork for the arrival of 800G. Recently, the QSFP-DD800 Multi-Source Agreement (MSA) organization released the first version of the QSFP-DD800 transceiver hardware specification, which is dedicated to the continuation of the current QSFP-DD form factor to support a single channel rate of 100Gbps 8-channel new generation QSFP-DD800. This also means that 800G might still adopt the QSFP-DD form factor to bring greater advantages and values for Internet service providers.

Article Source:

https://community.fs.com/blog/differences-between-qsfp-dd-and-qsfp-qsfp28-qsfp56-osfp-cfp8-cobo.html

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

https://community.fs.com/blog/400g-qsfp-dd-transceiver-types-overview.html

Infographic – Types of 400G Transceivers

With the tremendous requirement for high bandwidth in 5G, loT and cloud data center, the focus on 400G Ethernet has been lasting for several years. As the key hardware devices for optical network interconnection, 400G transceivers have also become the mainstream of the industry. The following is a brief introduction to the types of 400G transceivers.

https://community.fs.com/blog/infographic-types-of-400g-transceivers.html

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

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. 400G Direct Attached Cable

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. 400G Active Optical Cable

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 Connectivity

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-on-400g-transceivers-and-cables.html

https://community.fs.com/blog/fs-400g-cabling-solutions-dac-aoc-and-fiber-cabling.html

Why Choose FS Optics for 400G Deployment?

The increase in global data traffic has fostered the development of optical devices, which has led to data centers facing increasing challenges in cloud access, processing power, storage, and transmission bandwidth. Because of this, the 400G transceiver market is growing rapidly, and the choices of general optical modules are gradually diversifying. Customers also have many concerns when choosing optical products, so how do FS 400G transceivers solve these concerns to meet the needs, please read this article.

Concerns for Choosing 400G Transceivers

The choice of general 400G optical modules will face many problems. Customers usually struggle with how to choose good quality 400G optical modules and have some concerns, such as the choice of suppliers, the performance and compatibility of the optical module, etc.

General Transceivers or OEM Optics?

It is well known that general optical modules have cost advantages over their OEM counterparts and are provided on demand. In the rapidly growing 400G transceiver market, diversified suppliers have increased the difficulty of selecting general optical modules, and there also be some problems: incompatibility with existing equipment, prone to network delays leading to system restarts, or other unqualified after-sales services. Therefore, it is important to choose a supplier you trust.

400G Transceiver Quality Issues

The most common quality issues with 400G transceivers from general optical product suppliers are compatibility and reliability. Because ensuring compatibility means achieving high precision when coding optics to interoperate with OEM hardware, this problem is common among inexperienced suppliers. Failures caused by these quality issues can range from a lack of relevant functionality in equipment operation to catastrophic failures such as network, system reboots, or network outages. Whether the long-term performance of the optical module can remain as efficient as the first deployment is also a factor that customers need to consider. Otherwise, it will cause trouble later.

Consequences of Incorrect 400G Transceivers

OEM warranty is a recurring issue. There is a saying that using general products in their OEM hardware voids the warranty. But the optical module itself is unlikely to damage OEM equipment because 400G ethernet QSFP modules convert electrical data from devices into optical signals, which can prove that there is no input power from the optical port to damage the device.

At this point, the optical module will not function properly or appear to be incompatible with your equipment environment, and the IT manager needs to re-plan to take the necessary alternative strategies to resolve the failure. In this case, it takes a certain amount of time to communicate with optical product suppliers and arrange for engineers to conduct fault diagnosis. If a problem is diagnosed, the faulty product should be returned and a new product delivered for redeployment and equipment testing. Essentially, the resolution to these problems costs a lot of time and effort for IT managers, adding to the cost of wasted time.

Benefits of FS 400G Optical Modules

Compared with the existing optical module supplier market, FS optical modules have certain OEM equipment compatibility and reliability, can meet various transmission needs, and have high-quality after-sales service. At the same time, FS also has a one-stop procurement platform to support the procurement of a set of 400G optical products, which greatly improves your purchase efficiency and saves costs.

Transceiver Reliability

How FS ensures the reliability of its 400G optics? It is first reflected in their production process. FS 400G optical modules adopt the original equipment manufacturer (OEM) compatibility programming core capability, featuring interoperability with multiple suppliers. These transceivers provide high-quality optical connections at a lower cost and the same performance quality as the OEM brand. Also, the transceiver’s standardized features to OEM specifications ensure high component quality and suitability.

The second is the rigorous testing of the transceivers. FS optical modules are tested for compatibility on equipment by a professional technical team, as a way to eliminate errors and reduce the need for workarounds and system downtime. Even the equipment in use in your computer room can be tested to meet your expectations. This reduces the risk of network failures and ensures that the business remains up and running, providing uninterrupted service to customers. FS adheres to a 99.98% reliability rating, allowing you to enjoy quality products and services.

Multiple Choice and Trusted Services

FS can provide a variety of transceivers, and some may not be available from the OEM. FS has set up a global warehouse base with a large inventory of optical modules to connectivity needs of your network projects.

FS laboratory has an experienced team of professional technical experts and features perfect after-sales service. If you have any questions about the use of the product, you can directly contact the one-to-one sales representative to solve it. For example, if you want to know whether Juniper QSFP/OSFP works on Cisco platforms, FS will tell you based on specific lab tests and experience. Moreover, when you need to perform remote compatibility testing, the FS remote demo service can provide you with a better testing experience.

Cost-effectiveness

When you choose optical products for your 400G project, 400G optical transceivers may not be the only thing you require, network devices, optical cables and corresponding accessories, such as switches, wiring, or other accessories are also needed. Of course, when applying these components, you also need to consider their loss and fit. To better solve this problem, the FS 400G product series supports one-stop procurement to help you solve your deployment problems and make the products perfectly fit your needs, which can improve your procurement efficiency and save manpower and material costs. In addition, with its professional capabilities, FS can complete the testing, collection, distribution, acceptance, after-sales, and other work of the products you need, which is convenient for your equipment maintenance and management.

A one-stop procurement approach can reduce a company’s overall cost of investment (COI). For example, replacing 9 individual SKUs with one SKU at a simple price can simplify the procurement, inventory, and operational issues of optical modules. This reduces the time spent on multiple 400G optical module suppliers, and a high-quality supplier like FS can spend valuable time in other more important places, you can save up to 70% of the cost.

Explore FS 400G Optics Solutions

Facing the diverse general optic product supplier market, you should choose a supplier you trust, which will have a huge influence on your business. FS can be one of your best options as a general optical product supplier. With a professional technical team, global warehousing capabilities, remote demo services, and 400G transceivers with the same OEM performance, FS can ensure your high-performance network, optimize your operational efficiency, and minimize waste of time, effort, and budget.

Article Source:

https://community.fs.com/news/why-choose-fs-optics-for-400g-deployment.html

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

https://community.fs.com/blog/infographic-types-of-400g-transceivers.html

400G ZR & ZR+ – New Generation of Solutions for Longer-reach Optical Communications

400G ZR and ZR+ coherent pluggable optics have become new solutions for high-density networks with data rates from 100G to 400G featuring low power and small space. Let’s see how the latest generation of 400G ZR and 400G ZR+ optics extends the economic benefits to meet the requirements of network operators, maximizes fiber utilization, and reduces the cost of data transport.

400G ZR & ZR+: Definitions

What Is 400G ZR?

400G ZR coherent optical modules are compliant with the OIF-400ZR standard, ensuring industry-wide interoperability. They provide 400Gbps of optical bandwidth over a single optical wavelength using DWDM (dense wavelength division multiplexing) and higher-order modulation such as 16 QAM. Implemented predominantly in the QSFP-DD form factor, 400G ZR will serve the specific requirement for massively parallel data center interconnect of 400GbE with distances of 80-120km. To learn more about 400G transceivers: How Many 400G Transceiver Types Are in the Market?

Overview of 400G ZR+

ZR+ is a range of coherent pluggable solutions with line capacities up to 400Gbps and reaches well beyond 80km supporting various application requirements. The specific operational and performance requirements of different applications will determine what types of 400G ZR+ coherent plugs will be used in networks. Some applications will take advantage of interoperable, multi-vendor ecosystems defined by standards body or MSA specifications and others will rely on the maximum performance achievable in the constraints of a pluggable module package. Four categories of 400G ZR+ applications will be explained in the following part.

400G ZR & ZR+: Applications

400G ZR – Application Scenario

The arrival of 400G ZR modules has ushered in a new era of DWDM technology marked by open, standards based, and pluggable DWDM optics, enabling true IP-over-DWDM. 400G ZR is often applied for point-to-point DCI (up to 80km), making the task of interconnecting data centers as simple as connecting switches inside a data center (as shown below).

Figure 1: 400G ZR Applied in Single-span DCI

Four Primary Deployment Applications for 400G ZR+

Extended-reach P2P Packet

One definition of ZR+ is a straightforward extension of 400G ZR transcoded mappings of Ethernet with a higher performance FEC to support longer reaches. In this case, 400G ZR+ modules are narrowly defined as supporting a single-carrier 400Gbps optical line rate and transporting 400GbE, 2x 200GbE or 4x 100GbE client signals for point-to-point reaches (up to around 500km). This solution is specifically dedicated to packet transport applications and destined for router platforms.

Multi-span Metro OTN

Another definition of ZR+ is the inclusion of support for OTN, such as client mapping and multiplexing into FlexO interfaces. This coherent pluggable solution is intended to support the additional requirements of OTN networks, carry both Ethernet and OTN clients, and address transport in multi-span ROADM networks. This category of 400G ZR+ is required where demarcation is important to operators, and is destined primarily for multi-span metro ROADM networks.

Figure 2: 400G ZR+ Applied in Multi-span Metro OTN

Multi-span Metro Packet

The third definition of ZR+ is support for extended reach Ethernet or packet transcoded solution that is further optimized for critical performance such as latency. This 400G ZR+ coherent pluggable with high performance FEC and sophisticated coding algorithms supports the longest reach over 1000km multi-span metro packet transport.

Figure 3: 400G ZR+ Applied in Multi-span Metro Packet

Multi-span Metro Regional OTN

The fourth definition of ZR+ supports both Ethernet and OTN clients. This coherent pluggable also leverages high performance FEC and PCS, along with tunable optical filters and amplifiers for maximum reach. It supports a rich feature set of OTN network functions for deployment over both fixed and flex-grid line systems. This category of 400G ZR+ provides solutions with higher performance to address a much wider range of metro/regional packet networking requirements.

400G ZR & ZR+: What Makes Them Suitable for Longer-reach Transmission in Data Center?

Coherent Technology Adopted by 400G ZR & ZR+

Coherent technology uses the three degrees of freedom (amplitude, phase and polarization of light) to focus more data on the wave that is being transmitted. In this way, coherent optics can transport more data over a single fiber for greater distances using higher order modulation techniques, which results in better spectral efficiency. 400G ZR and ZR+ is a leap forward in the application of coherent technology. With higher-order modulation and DWDM unlocking high bandwidth, 400G ZR and ZR+ modules can reduce cost and complexity for high-level data center interconnects.

Importance of 400G ZR & ZR+

400G ZR and 400G ZR+ coherent pluggable optics take implementation challenges to the next level by adding some of the elements for high-performance solutions while pushing component design for low-power, pluggability, and modularity.

Conclusion

Although there are still many challenges to making 400G ZR and 400G ZR+ transceiver modules that fit into the small size and power budget of OSFP or QSFP-DD packages and also achieving interoperation as well the costs and volume targets. With 400Gbps high optical bandwidth and low power consumption, 400G ZR & ZR+ may very well be the new generation in longer-reach optical communications.

Original Source: 400G ZR & ZR+ – New Generation of Solutions for Longer-reach Optical Communications