Understanding the Specifications of QSFP28 Transceivers


In the world of high-speed networking, the demand for faster data transmission and greater bandwidth has driven the development of advanced optical transceiver modules. 

One such module is the Quad Small Form-Factor Pluggable 28 (QSFP28) transceiver. QSFP28 has become the industry standard for high-density, high-performance networking applications. In this article, we will delve into the specifications of QSFP28 and explore its capabilities.

  1. Form Factor and Connector

QSFP28 is designed to be a compact and hot-pluggable optical transceiver module. It follows the same form factor as its predecessors, such as QSFP and QSFP+. The transceiver module measures approximately 18 mm x 72 mm x 8.5 mm in size, allowing for high-density deployment in networking equipment. It utilizes a 38-pin connector interface for power supply, control signals, and high-speed data transmission.

  1. Data Rate and Reach

The most significant advantage of QSFP28 is its ability to provide extremely high data rates. It supports data rates of up to 100 gigabits per second (Gbps) per channel, with a total aggregate bandwidth of 400 Gbps (4 channels). This makes it ideal for next-generation data centers, cloud computing, and other bandwidth-intensive applications.

In terms of reach, QSFP28 supports various types of optical interfaces, including multi-mode fiber (MMF) and single-mode fiber (SMF). The reach of QSFP28 modules depends on the type of fiber and the modulation format used. Typically, QSFP28 can achieve distances ranging from a few meters to tens of kilometers, depending on the specific module and the fiber type.

  1. Electrical and Optical Interfaces

QSFP28 transceivers support both electrical and optical interfaces. The electrical interface complies with the industry-standard high-speed electrical specifications, such as CEI-28G and OIF-CEI. These interfaces ensure reliable and low-latency data transmission within networking equipment.

For the optical interface, QSFP28 modules utilize different types of optical components, including vertical-cavity surface-emitting lasers (VCSELs) for multi-mode applications and directly modulated lasers (DMLs) or electro-absorption modulated lasers (EMLs) for single-mode applications. These components enable the transceivers to transmit and receive data over different types of optical fibers.

  1. Supported Protocols and Applications

QSFP28 transceivers are designed to support a wide range of industry-standard protocols and applications. Some of the commonly supported protocols include Ethernet (10/25/40/50/100 Gbps).

InfiniBand (EDR/FDR/QDR), Fibre Channel (16G/32G), and SONET/SDH. This versatility allows QSFP28 modules to be used in various networking environments, from enterprise networks to high-performance computing clusters.

  1. Power Consumption and Heat Dissipation

Power consumption and heat dissipation are crucial factors in data center environments. QSFP28 transceivers are designed to be power-efficient while maintaining high-performance capabilities. 

The power consumption of QSFP28 modules typically ranges from 3.5 to 4.5 watts per module, depending on the specific application and configuration.

Heat dissipation is achieved through the use of advanced thermal management techniques, including integrated heat sinks and low-power components. These measures help to maintain the module’s optimal operating temperature and ensure reliable performance.


In summary, QSFP28 transceivers have become the de facto standard for high-speed, high-density networking applications.The power consumption of QSFP28 modules typically ranges from 3.5 to 4.5 watts per module, depending on the specific application and configuration. With its compact form factor, high data rates, and support for various protocols, QSFP28 enables seamless integration into modern data centers and network infrastructure.


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