What is SFP+ Module? An Ultimate Guide (2024)

Initially posted on May 2, 2017

In the previous post, we explained the SFP module and learned its basics. As one of our tutorial series, we focus on the SFP+ module today. In this ultimate guide, we will answer the following question:

• What is an SFP+ module?
• SFP+ module history
• Why is it important? 
• SFP+ benefits
• What is an SFP+ connector?
• How many types are there?
• How do I choose the SFP+ module?
• FAQ
• Final thoughts

Now, let’s dive into learning more about SFP+.

What is an SFP+ module?

Simply speaking, SFP+ is an enhanced SFP form factor supporting a higher speed of 8G/10G/16G. An SFP+ module is an enhanced small form factor pluggable transceiver that fits into the SFP+ port of the switch or other networking device. A complete SFP+ system comprises an SFP+ module, SFP+ port, SFP+ cage, and SFP+ connector in the hosting device.

The SFP+ module is also called the SFP+ transceiver, SFP+ optical module, SFP+ optics, or SFP+ fiber transceiver. Although they have several different names, they are the same product. However, most vendors refer to it as an SFP+ module and transceiver. Searching for it on Google will find plenty of SFP+ suppliers, vendors, or shops. 

Compared with the SFP module, the SFP+ module supports a higher speed of 8GFC, 10Gbps, and 16GFC. Furthermore, it features a required built-in DDM/DOM (digital optical monitor) per SFF-8472, while the SFP module does not require this function. 

A typical SFP+ module comprises a cage, PCBA, chip, and optical TOSA+ROSA (sometimes BOSA for a BiDi transceiver). See the image below.

To help better understand the SFP+, we briefly introduce the basic SFP+ MSA (multi-source agreement). SFF-8431 and SFF-8432, launched by the SFF Committee, define the electrical characteristics and mechanical specifications of the SFP+ module and host. Click here to learn more about the MSA.

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FURTHER READING

• What is SFP Module? An Ultimate Guide (2023)
• How to calculate the Fiber Link budget?
• SFP28 vs SFP+ Transceiver, what is the difference?

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A Brief History of SFP+ Module 

First, let us discuss the SFP+ industry standards. The SFF Committee published the first SFP+ specification on May 9, 2006. Over the next few years, they updated and improved the specification to meet industry demand. The latest version of SFF-8431 is Rev4.1, updated on September 15, 2013.

From the day of his birth, SFP+ has shown powerful allure to the industry. SFP+ offers higher speed than SFP while holding the same small size. Therefore, it allows the manufacturer or vendors to increase port density by 4 to 10 times without changing the SFP-based mechanism. For the past XFP application scenarios, SFP+ also provides a better replacement choice. 

Today, the industry has vast networking switches and devices based on SFP+. The rich industry chain and user base have accelerated the maturity of SFP+ and, more importantly, have contributed to the dramatic drop in cost, further boosting its development. 

Why is the SFP+ module important? 

Consider your switch without an optical module. How do you achieve high speeds such as 10Gbps? The answer may be an ethernet cable. However, it is not feasible due to thickness, expense, and short-distance constraints.

That is where the SFP+ module comes in. Plugging a transceiver into the switch’s SFP+ port allows you to communicate with another switch over fiber for tens to hundreds of kilometers. 

For example, a 10GBASE-SR SFP+ module offers a maximum distance of 300m over multimode OM3 fiber, and Optcore’s price is as low as US$10.0; a 10GBASE-ZR SFP+ module provides a maximum length of 80km over single mode fiber, and Optcore price is as low as US$145.0.

Benefits of SFP+ Module

There are many benefits to SFP+. We highlight the most critical benefits below:

• High speed: SFP+ provides a much higher speed than the standard SFP module, which meets the dramatically demanding data traffic growth. 
• Hot pluggable: it is perfect for expanding or modifying existing networks without completely changing the cable infrastructure.
• Compact size: same as the standard SFP size and appearance, the SFP+ compact design provides high port density and saves space. 
• Lower cost: As one of the most successful form factors in the industry, SFP+ offers a great shipment, and plenty of suppliers offer lower fees.
• Comprehensive interoperability: optical interoperates with the traditional XFP, X2, and XENPAK modules, efficiently upgrading the old cabling to modern networking.

What is SFP+ Connector 

The SFP+ connector is a physical interface for accepting an SFP+ module, AOC, or DAC cable. It is one of the critical components of the SFP+ system. The typical SFP+ connector appearance is like the one below.

Unlike the SFP+ connector, the SFP+ fiber connector mainly refers to the fiber connector of an SFP+ module. The most common SFP+ fiber connector is LC duplex or LC simplex. Due to the limited space of the SFP+ cage, the SC connector is unavailable for them.

SFP+ Module Types

Because so many SFP+ modules are on the market, many individuals need to understand the various classes. As a result, selecting the correct transceiver may be a question.

Following that, we will attempt to categorize them using various standards.

By SFP+ Speed

• 10G SFP+: usually stands for 10Gbps speed, widely used in 10G Ethernet, SDH/SONET OC192, and 10G fiber channels (10GFC). It is the most popular SFP+, and most enterprise switches accept this type.
• 8G SFP+: specific 8G fiber channel speed for storage application, suitable for 8GFC SAN switches like Brocade and Cisco. 
• 16G SFP+: specific 16G fiber channel speed for storage application, suitable for 16GFC SAN switches like Brocade and Cisco

By SFP+ Media Type

• Copper SFP+: transmit the signal with traditional copper cables, typical types including RJ45 SFP+ and DAC cable
• Multimode Fiber (MMF) SFP+: supports OM1, OM2, OM3, OM4, and OM5 cabling. Higher fiber grade provides better performance.
• Singlemode Fiber (SMF) SFP+: suitable for 9/125 single mode fiber cabling, it provides the max link distance of 100km for 10Gbps.

By SFP+ Transceiver Protocols 

• 10GBASE-T: Similar like 1000BASE-T, typcial transmission distance 30m over Cat6a or better ethernet cable.
• 10GBASE-SR: stands for 10Gbps short reach. It is defined in the IEEE 802.3an; 10GBASE-SR reaches 300m on multimode OM3 fiber.
• 10GBASE-LR: stands for 10Gbps long reach. It is defined in IEEE 802.3ae, 10GBASE-LR supports 10km on single mode fiber.
• 10GBASE-LR20: stands for 10Gbps long reach 20km. It is not defined in IEEE 802.3ae, but is accepted by some vendors. 
• 10GBASE-LRM: stands for 10Gbps long reach over multimode fiber. It is defined in IEEE 802.3ae, 10GBASE-LRM reaches 220m on OM3 fiber.
• 10GBASE-ER: stands for 10Gbps extended reach. It is defined in IEEE 802.3ae. 10GBASE-ER reaches 40km on single mode fiber.
• 10GBASE-ZR: This also stands for extended reach and is defined in IEEE 802.3ae. It supports 80km on single-mode fiber and uses 1550nm wavelength.
• 10GBASE-EZR is not an official standard, but it is commonly used by certain manufacturers and vendors. This technology supports distances of up to 100km over single-mode fiber and operates at a wavelength of 1550nm. It is designed for specific long-reach applications like backbone and metropolitan area networks.

By Application

• Regular SFP+: most commonly SFP+ transceiver with a duplex fiber
• CWDM SFP+: support CWDM transmission to improve the bandwidth in one fiber
• DWDM SFP+: support DWDM transmission to maximize the bandwidth 
• BiDi SFP+: SFP+ transceiver supports Bi-directional communication in single-strand fiber
• Fibre Channel SFP+: covers the speed of 8G and 16G, mainly used in the storage network and device
• Compact SFP+: The CSFP+ transceiver integrates two BiDi SFP+ transceivers in a single SFP+ package. The compact SFP+ allows two-channel transmission and saves a half-size port, which is ideal for high-density applications.
• PON SFP+:  include the XGSPON and 10G EPON transceiver, standards for 10G passive optical networking, mainly for the FTTX application
• SFP+ DAC Cable: it is a direct attach copper cable with an SFP+ connector on both ends, a lower-cost solution for very short length
• SFP+ AOC Cable: is an active optical cable with an SFP+ connector on both ends, supporting longer distances than DAC cable.

Figure 5: SFP+ RJ45 vs. LC duplex (From left to right)

By Connector Type

• SFP+ LC: LC is the default connector for most SFP+ transceivers
• SFP+ RJ45: This 10G transceiver has a female RJ45 connector to accept network cable.

By Operating Temperature

• Commercial grade: the typical SFP+ transceiver supports 0~70°C commercial temperature. It provides the best pricing and cost ratio and is suitable for a standard indoor environment like a data center or enterprise.
• Industrial grade: it’s an SFP+ transceiver that supports -40~85°C hardened temperature. Suitable for industrial switches and other devices in the outdoor environment. 
• Extended grade: this one is not the standard type. It can handle the -10~85°C temperature. 

By Compatible Platform

Since many networking device brands exist, some top vendors locked the SFP+ port to prevent the generic modules. That is the value of compatible transceivers. The most popular compatible platforms include Cisco, Arista, Juniper, Brocade, etc.

In reality, there are several ways to classify them. However, the most prevalent techniques are categorized according to data speed and application. Significantly, the same SFP+ transceiver may be classified in many ways. For example, the compatible Cisco SFP-10G-SR-S will be included in charts like 10G, multimode, regular, 10GBASE-SR, LC, and commercial transceiver. 

How to Choose the Correct SFP+ Module? 

We help more than 1400 clients choose the suitable SFP+ transceiver quickly. Here are the essential tips.

1. Check your switch (or other network devices) port-supported speed and match the correct SFP+.
2. Know your existing network cabling types. If you have a multimode fiber cabling structure, choose the multimode SFP+. A single-mode transceiver is the only choice if you have single-mode fiber cabling.
3. Know your target link distance and link budget. But remember, choose an SFP+ that supports longer transmission distances than expected. Otherwise, poor fiber optic cable or a dirty fiber end face may cause a failed link.
4. Considering the operating temperature, a commercial-grade SFP+ transceiver is enough for a typical indoor environment. In harsh outdoor applications, you should use an industrial transceiver.
5. Remember to check compatibility with the vendor before ordering. You will waste money and time because the switch will not identify an incompatible transceiver. As a result, always use a known compatible transceiver.

FAQ

Q: SFP vs. SFP+. What is the difference? 

A: The critical difference is the data transmission speed. SFP supports the typical rate of 155M, 1.25G, and 2.5G, whereas the SFP+ supports 10G and 8G/16GFC. 

Q: What is the maximum transmission distance of the SFP+ module?

A: It depends on the SFP+ speed. Take the 10G SFP+ as an example; most vendors provide an 80km version, but Optcore may provide an ultra-long distance of 100km over single mode fiber.

Q: Can I connect an SFP+ with an XFP module?

A: The answer is yes. But make sure that they have the same transmission speed and wavelength. Or else they will fail to establish a link.

Q: Can you provide the SC SFP+ module?

A: We’re sorry, but we can not provide an SC SFP+ transceiver. Although some guys use the SC cabling system for 10G speed, finding manufacturers that provide specific SFP+ is difficult. In this case, you only need an LC-SC fiber jumper to convert the connector quickly.

Q: I have two BiDi SFP+ transceivers connected via a single fiber cable, but they failed to connect. What could be the problem?

• First, check if the BiDi SFP+ wavelength is paired correctly. All BiDi transceivers must be paired with the opposite wavelength on the other end. Ex Side A is 1270nm-TX/1330nm-RX, and Side B should use 1330nm-TX/1270nm-RX.
• Second, check if the actual distance exceeded the module’s allowed max distance.

Final thoughts 

We’ve discussed the meaning of the SFP+ module and its several types.

Do you understand the fundamentals?

Which SFP+ are the most well-known in your network?

Which SFP+ module vendor is your favorite?

Please notify me by writing a comment. 

Let me know by leaving a comment. 

Reference:

• https://www.snia.org/technology-communities/sff/specifications

Read More:

• What is GBIC Transceiver?
• What is SFP Module? An Ultimate Guide
• What is SFP Port? Everything You Need to Know
• The Big Differences Between SFP, SFP+, SFP28, QSFP+, QSFP28, QSFP-DD, and OSFP
• What is QSFP-DD Transceiver: A Beginner Guide (2022)