What is QSFP-DD

In today’s blog article we will talk a little bit about SFP and QSFP Components, and learn deeper about the big brother of the QSFP family: QSFP-DD.

Let’s Talk About SFPs First

Firstly, let’s briefly remember what SFP Transceivers are: SFP stands for small form-factor pluggable, SFP Transceivers are network equipment that are used as interface modules between network components and copper/fiberoptic cabling. SFP Transceivers are small and hot-pluggable components, and they are used widely in many networking applications, they have transmitter and receiver in themselves. Their hot-pluggable nature allows them to be installed into the system without the need to shut it down or restart it. Specifications of SFP Transceivers can be summarized as data rate, range, physical media, number of channels, compatibility, and cost. There are many types of SFPs for individual or industrial networking needs.


And What Are QSFPs

Simply put, QSFP’s are an expansion to the original SFP family which is developed for larger-scale applications. QSFP stands for “Quad Small Form-factor pluggable”. The Quad in the name simply defines that it has 4 channels. The channel size in QSFP modules allows them to quadruple the data rate with respect to the same level SFPs. Much like their predecessor SFPs, QSFPs are also compact, hot-pluggable, and they are used for very similar applications as SFPs. QSFPs, just like standard SFPs, are manufactured in accordance with Multi-Source Agreement (MSA) Standards, which means they are mostly compatible with products of other vendors.

relative link: How Many Types of 40G QSFP are Available?


Getting To Know QSFP-DD

Now, let’s introduce our guest of honor: QSFP-DD. To mention its full name, QSFP-DD stands for quad small form-factor pluggable double density. QSFP-DD is the big brother of the QSFP family. And while the quad in the name may make someone think that it has 4 channels, since it’s a double density component, it actually consists of 8 channels. It is one of the highest standard SFP components available in the market. QSFP-DD module is compliant with the IEEE 802.3cu for 100GBASELR1, and 400GAUI-8/CEI-56G-VSR-PAM4 standards.

QSFP DD modules
QSFP DD modules

QSFP-DD Transceivers consist of eight-lane of data each of which supports up to 50Gbps, allowing the unit to support a 400 Gbps data rate, which is why they are often referred to as QSFP 400G. Since these modules support a very heavy data flow-through, they are the primary candidates for 400 Gigabit Ethernet (400GBase) applications, which is one of the highest data rates of the Ethernet world. However, saying QSFP-DD’s networking applications are solely limited to this would not be correct.

Range of QSFP-DD Transceivers vary highly from one to another, every component can use a different wavelength which gives it a different distance range. Furthermore, they can operate over Single-Mode or Multi-Mode fiber optical medium, so we can say there are both short-range (SR) and long-range (LR) modules available in the market. The technology used in them which the range to be from low as couple meters to high as 40 kilometers. The range of this product allows it to be used in a big variety of situations.

Looking at the physical properties of the device, QFSP-DD is 156mm2. For the data transmission medium QSFP-DD module uses for data transmission, the transceiver can use passive direct attached copper cables (DAC), multi-mode fibers and single-mode fibers. The device is equipped with an LC connector as well. The operating temperature of the module is defined between 0 to 70 °C, and the storing temperature is between -40 and 85 °C.

While it isn’t truly possible to say anything concrete about the cost of the module, since it would change from vendor to vendor, when the strong specifications of QSFP-DD are considered, the transceiver offers a cost-effective network solution. Especially for large-scale applications with heavy data flow, this module is crucial for effectiveness.

As many other SFP and QSFP modules, as aforementioned QSFP-DDs are also manufactured according to MSA, so it would be reasonable to assume they would work with the majority of networking equipment as long as there is nothing that prevents third party components, i.e., vendor lock-in practices. The device is also back compatible, making it a suitable choice for many settings. There are many manufacturers for QSFP-DD products such as Cisco, Juniper, and Arista.

Dimensions of QSFP-DD are in millimeters. (Unit: mm)
Dimensions of QSFP-DD are in millimeters. (Unit: mm)

Where Do We Use QSFP-DDs?

As our world becomes more internet-dependent the need for faster, more reliable internet grows. The older internet infrastructures no longer suffice the networking needs of today’s world. Standards for the internet keep evolving. Currently, 400Gbit/s networks are the highest standard of network achieved with the existing technology and the QSFP-DD module plays a key part in this networking evolution. As 400 Gigabit Ethernet becomes commercially available, the need for stronger networking modules grows rapidly. Currently, the QSFP-DD is mainly used to apply 400G networks that are being deployed.

We have mentioned that QSFP-DD supports a very heavy data flow to a variety of distances. While it is possible to see the QSFP-DD transceiver being used in many settings, it is exclusively used in high-performance data centers. The range and data flow also make it a primary choice for cloud networking applications as well. With the increasing network needs, the QSFP-DD transceivers get a larger place in the network industry every day.

Let’s Wrap it Up

The QSFP-DD module offers a 400Gbps data rate using 8 data lanes. There are a variety of range options available which let users pick whichever fits the best to their use case. In a continuously evolving world with growing networking needs, the QSFP-DD module is currently of the highest standard network components. Furthermore, it can be said that the continuation and improvement of the current QSFP-DD product will also aid the developments in future networking applications.

Before we go, let us remind you to check out QSFPTEK offers an amazing selection for all your networking needs! Whether you are just an individual network user, or a company building a huge network infrastructure, make sure to check the QSFPTEK website to find explore the best options for you.