QSFP28-DD Optical Module: Introduction and Guide Manual

Table of Contents

Hi, I am happy to introduce you to the knowledge of QSFP28-DD (Quad Small Form-factor Pluggable 28 Double Density) optical module. In this article, I will introduce to you the definition, basic principles of QSFP28-DD as well as its characteristics and advantages as a high-density optical module. At the same time, I will also discuss the application of QSFP28-DD optical modules in data center networks and high-performance computing, and provide information on the technical standards, compatibility, deployment configuration, etc. of QSFP28-DD.

Introduction to QSFP28-DD Optical Module

Definition and rationale:
QSFP28-DD (Quad Small Form-factor Pluggable 28 Double Density) is a high-density optical module, which is an evolved version of the QSFP series. The QSFP28-DD module adopts a 28-channel design, and each channel supports transmission rates up to 25 Gbps or higher. It provides high-bandwidth and high-rate data transmission and is suitable for applications such as data centers and high-performance computing.

The basic principle of QSFP28-DD is similar to other QSFP modules. It uses a multi-channel design where each channel contains a pair of optical fibers (for transmit and receive) or a pair of copper cables (for cabling). Through photoelectric conversion and modulation and demodulation technology, the QSFP28-DD module can convert data into optical signals for transmission, and convert the optical signals back to electrical signals at the receiving end.

Plug-in type:
As a high-density optical module, QSFP28-DD has the following characteristics and uses:

  1. High-density connection: The QSFP28-DD module adopts a miniaturized plug-in size and can provide multiple channel connections in a limited space. Its density is twice that of the QSFP28 module, which can effectively increase the number of connection ports and achieve high-density wiring and connections.

  2. High-rate transmission: Each channel supports transmission rates up to 25 Gbps or higher. Since the QSFP28-DD module has 28 channels, the total bandwidth of the entire module can reach 700 Gbps or higher. This makes it suitable for applications requiring large bandwidth and high-speed transmission, such as intra-data center interconnects and high-performance computing.

  3. Flexible applications: QSFP28-DD modules can be used in a variety of application scenarios, including Ethernet, Fiber Channel, data center interconnection, high-performance computing and storage networks, etc. It provides flexible connectivity options, with fiber or copper cables available for connection depending on your needs.

  4. Backward compatibility: Although QSFP28-DD is an evolved version of QSFP28, it still maintains backward compatibility. This means it can interoperate with QSFP28 modules and other QSFP series modules, making it more convenient to upgrade and expand existing networks.

In summary, QSFP28-DD is a high-density optical module that provides high-bandwidth and high-rate data transmission capabilities through multi-channel design and high-rate transmission. It has broad application prospects in fields such as data centers and high-performance computing.

QSFP28-DD Optical Module application fields

Data center network:
QSFP28-DD modules are widely used in data center networks, mainly in the following aspects:

  1. High-speed data transmission: Data centers need to handle a large amount of data traffic, and the QSFP28-DD module provides a transmission rate of up to 25 Gbps or higher, enabling data centers to achieve fast and efficient data transmission. It can cope with the internal interconnection needs of large-scale data centers and support fast communication and data exchange between servers.

  2. Dense connection requirements: Dense connections are required between servers, storage devices and network devices within the data center. The high-density design of the QSFP28-DD module allows a large number of connections within a limited physical space to meet the dense connection needs of data centers. It can be connected via fiber optic or copper cables, providing flexible options.

High performance computing:
The QSFP28-DD module also has important applications in the field of high-performance computing, mainly in the following aspects:

  1. High-bandwidth communication: High-performance computing systems require high-bandwidth communication to support large-scale parallel computing and data transmission. The QSFP28-DD module’s high-rate transmission capability and 28-channel design enable it to provide high-bandwidth communication capabilities and meet the needs of high-performance computing systems for large-scale data exchange.

  2. Low-latency communication: High-performance computing has very high requirements for low-latency communication to ensure fast data transmission and collaborative computing between computing nodes. The QSFP28-DD module can achieve low-latency communication and support the requirements of high-performance computing systems by providing fast photoelectric conversion and high-rate data transmission.

  3. High-density cabling: High-performance computing systems usually require a large number of computing nodes and storage devices, and dense connections between them. The high-density design of the QSFP28-DD module enables it to connect a large number of nodes within a limited physical space, simplifying the wiring structure and improving the scalability and flexibility of the system.

The QSFP28-DD module has important applications in data center networks and high-performance computing. It can support high-speed data transmission, dense connections and high-bandwidth low-latency communications to meet the needs of data centers and high-performance computing systems for high-performance and efficient communications.

QSFP28-DD Optical Module features and advantages

High speed transmission:
The QSFP28-DD module has high-speed data transmission capabilities. Its features and advantages include:

  1. Multiple protocol support: The QSFP28-DD module supports multiple protocols, including Ethernet, Fiber Channel and other high-speed data transmission protocols. This makes it widely applicable in different application scenarios and can meet the needs of different systems and networks.

  2. High transmission rate: Each channel supports transmission rates up to 25 Gbps or higher. Since the QSFP28-DD module has 28 channels, the total bandwidth of the entire module can reach 700 Gbps or higher. This enables it to handle large amounts of data traffic, enabling fast and efficient data transfer.

  3. Future scalability: In addition to supporting the current transmission rate, the QSFP28-DD module also has the ability to expand in the future. It can adapt to growing data demands and support higher transfer rates, thereby ensuring system scalability and durability.

Dual density design:
As a dual-density optical module, the QSFP28-DD module has the following advantages:

  1. Higher port density: Compared with traditional QSFP modules, the QSFP28-DD module has higher port density. Its dual-density design allows for more connection ports in limited physical space, providing greater expansion capabilities and cabling flexibility.

  2. Flexible connection options: The QSFP28-DD module can be connected through optical fiber or copper cable, providing flexible connection options. This enables it to adapt to different network environments and needs and meet diverse application scenarios.

  3. Backward compatibility: The QSFP28-DD module maintains backward compatibility with QSFP28 and other QSFP series modules. This means it can interoperate with older versions of QSFP modules, making network upgrades and expansions more convenient and seamless.

To sum up, the QSFP28-DD module has the characteristics and advantages of high-speed transmission and double-density design. It provides high-speed data transfer capabilities, supporting multiple protocols and transfer rates, along with high port density and flexible connectivity options. This makes the QSFP28-DD module an important choice in fields such as data centers and high-performance computing.

QSFP28-DD Optical Module technical standards and specifications

Optical module structure:
The structural features of the QSFP28-DD optical module are as follows:

  1. Number of ports: The QSFP28-DD module adopts a double-density design, with each module having 8 or 16 ports. This allows it to provide higher port density and support more connection needs.

  2. Fiber type: QSFP28-DD module supports multiple fiber types, including multi-mode fiber (MMF) and single-mode fiber (SMF). The specific type of optical fiber used depends on the application scenario and transmission distance requirements.

  3. Power supply: QSFP28-DD modules usually use a single power supply, and the operating voltage is generally 3.3V. It also includes power management features to ensure proper operation and stability of the module.

letter of agreement:
The QSFP28-DD optical module supports a variety of communication protocols, including but not limited to the following:

  1. Ethernet: The QSFP28-DD module widely supports Ethernet protocols, including various Ethernet rates, such as 10GbE, 25GbE, 40GbE, 50GbE, 100GbE, etc. It can be used in areas such as data center networks, enterprise networks, and cloud computing.

  2. InfiniBand: The QSFP28-DD module also supports the InfiniBand protocol, which is mainly used for high-performance computing and data center interconnection. It provides high-bandwidth and low-latency communication capabilities to meet the needs of large-scale computing and data transmission.

  3. Fiber Channel: The QSFP28-DD module also supports the Fiber Channel protocol in the storage field. Fiber Channel is a high-performance transport protocol for storage area networks (SANs) that supports reliable data transfer and storage connections.

In addition to the communication protocols listed above, the QSFP28-DD module can also support other high-speed data transmission protocols, which can be configured and used according to specific application requirements.

In short, the structural characteristics of the QSFP28-DD optical module include the number of ports, fiber type, and power supply. It supports multiple communication protocols, such as Ethernet, InfiniBand and Fiber Channel, to meet the needs of different fields and application scenarios.

QSFP28-DD Optical Module compatibility and interface types

Compatibility points:
The compatibility points of the QSFP28-DD optical module mainly include the following aspects:

  1. Backward compatibility: The QSFP28-DD module has backward compatibility and can interoperate with older versions of QSFP modules (such as QSFP28, QSFP+, etc.). This means that the QSFP28-DD module can be compatible with existing devices and network interfaces without replacing the entire system.

  2. MSA standard: The QSFP28-DD module follows the Multi-Source Agreement (MSA) standard, which is an industry consensus that ensures functional and interface compatibility of optical modules from different suppliers. Therefore, the QSFP28-DD module can be used with devices and interfaces that comply with MSA standards.

  3. Versatility: QSFP28-DD modules are widely used in data centers, enterprise networks, cloud computing and other fields, and are compatible with various network equipment and switches. It can connect with different makes and models of devices, providing flexible deployment options.

Interface Type:
The common interface types of QSFP28-DD optical modules mainly include the following two types:

  1. QSFP-DD interface: The QSFP28-DD module adopts the QSFP Double Density (QSFP-DD) interface. This interface is based on the QSFP standard, but achieves higher bandwidth and greater port density by adding more channels and pins. The QSFP-DD interface supports the high-speed data transmission and double-density design of the QSFP28-DD module.

  2. OSFP interface: The QSFP28-DD module can also use the Octal Small Form-factor Pluggable (OSFP) interface. The OSFP interface is a standard interface for high-speed optical modules that can support higher transmission rates and greater port density. The OSFP interface differs from the QSFP-DD interface in physical size and pin configuration, but can provide similar functionality and performance.

It should be noted that QSFP28-DD modules usually have a QSFP-DD interface, but in some cases an OSFP interface may also be selected, depending on system requirements and device compatibility.

To sum up, the QSFP28-DD optical module has backward compatibility, is compatible with older versions of QSFP modules, and complies with MSA standards. It usually adopts QSFP-DD interface, and OSFP interface can also be selected to meet the needs of different systems and devices.

QSFP28-DD Optical Module deployment and configuration

Optical module installation:
The following is the general installation guide for the QSFP28-DD optical module, including connection and fixing steps:

  1. Ensure that the equipment is powered off: Before installing the optical module, please ensure that the relevant equipment is powered off and follow relevant safety operating procedures.

  2. Align and insert: Align the connection port of the QSFP28-DD optical module with the slot of the device. Then, gently insert the optical module, making sure that the plug is in full contact with the slot and that the connection is secure.

  3. Fix the optical module: According to the design and requirements of the equipment, use appropriate fixing means (such as screws, buckles, etc.) to fix the QSFP28-DD optical module in the slot. This helps ensure a strong and stable connection.

  4. Connect the optical fiber: Connect the appropriate type of optical fiber to the optical fiber interface of the QSFP28-DD optical module as needed. Make sure the fiber connections are secure and avoid bending or overstretching the fiber.

  5. Power supply and startup: Provide appropriate power supply for the QSFP28-DD optical module according to the requirements of the device. Then, according to the device startup process, start the optical module and perform necessary configurations.

Network Configuration:
The network configuration method of the QSFP28-DD optical module may vary depending on the device and application. The following is a general network configuration method:

  1. Port configuration: Configure the port connected to the QSFP28-DD optical module according to network requirements. This includes specifying the port’s speed, protocol type (such as Ethernet, InfiniBand, etc.) and other related parameters.

  2. Transmission parameter adjustment: According to the actual situation, adjust the transmission parameters to optimize the performance of the optical module. This may involve adjusting transmission rates, forward error correction (FEC) settings, equalizer settings, etc.

  3. Network monitoring and management: Configure network monitoring and management tools to monitor the status, performance and fault conditions of the QSFP28-DD optical module. This can include using SNMP (Simple Network Management Protocol) or other management interfaces port for remote management and monitoring.

It should be noted that the specific network configuration methods and steps may vary depending on the device and network environment. It is recommended to refer to the documentation of the relevant device and the guide provided by the manufacturer to obtain accurate deployment and configuration information.

Future Development Trend of QSFP28-DD Optical Module

Future trends:
The QSFP28-DD optical module has great development potential in terms of technology and applications. The following are some future development trends:

  1. Higher transmission rate: As network demands increase, QSFP28-DD optical modules may achieve higher transmission rates in the future. For example, 400 Gbps and 800 Gbps modules are already in the development and standardization process and are expected to further increase network bandwidth.

  2. Expanded application fields: QSFP28-DD optical modules are not only widely used in data centers and enterprise networks, but are also expected to expand their applications in other fields, such as 5G communications, high-performance computing, and artificial intelligence. The increasing demand for high-density wiring and high-speed transmission in these fields will promote the further development and application of QSFP28-DD modules.

  3. Technological innovation: With the continuous development of optical communication technology, the QSFP28-DD optical module may benefit from new technological innovation. For example, advances in photonic integration technology, new modulation formats and forward error correction technology may bring higher performance and lower power consumption to the QSFP28-DD module.

The QSFP28-DD optical module achieves a more compact and scalable network architecture through high-density wiring, with the advantages of high bandwidth and double-density design. In the future, with the advancement of technology and the expansion of application fields, the QSFP28-DD module is expected to achieve higher transmission rates and be used in a wider range of fields. Technological innovation will also promote the development of QSFP28-DD modules, providing higher performance and lower power consumption.


Thank you for reading the introduction about QSFP28-DD optical module. As a high-density optical module, the QSFP28-DD optical module has unique advantages in high-speed data transmission and dense connections. Its high-speed transmission capabilities, dual-density design, and compatibility with other devices make it widely used in data center networks and high-performance computing.

In the future, QSFP28-DD optical modules are expected to continue to develop in technology and applications, achieving higher transmission rates and wider application fields. If you have any further questions about the QSFP28-DD optical module or want to know more information, please continue to follow GracyFiber Company, we will be happy to help you. Thanks!

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