You might have heard of 10GB technology. Even 100G technology. But the world's pace has changed in the past few years. There is another one— 400G technology. It is four times the 100G technology and provides a faster data speed without compromising the network latency.
In the 400G technology, transceivers play a crucial role. Among these, two essential types connect the devices and routers to transmit the data:
● OSFP (Octal Small Form Factor Pluggable)
● QSFP-DD (Quad Small Form Factor Pluggable – Double Density
Do you want to know both? Today, we will compare both and guide data center operators in selecting the right solution.
OSFP stands for Octal Small Form Pluggable transceiver, a module that offers advanced features and a high data transmission speed of up to 400 G. With eight electrical lanes, it is ideal for Ethernet technology and comes with the following specifications.
● Electrical lanes: 8 x 50Gbps PAM4
● Dimensions: ~100 mm x 22.58 mm x 13 mm
● Power consumption: Up to 15W (can support up to 18W with proper cooling)
● Interface: Various fiber types, including MPO, LC, and duplex
● Reach: Varies by type (SR8, DR8, FR4, LR4) from 100m to 10km+
Thermal performance to bandwidth, OSFP is an ideal choice in various cases. It has the following advantages.
● Superior thermal performance. It has powerful cooling features that dissipate the heat due to its larger structure. Therefore, it can work in harsh conditions without losing much energy and overheating.
● High bandwidth capacity. AI clusters, high-performance computing (HPC), and intra-datacenter connections require a high bandwidth. That is what an OSFP feeds the system to let it run.
● Futuristic design. OSFP transceiver is designed with future expansion in mind. For example, it has an 800G and 1.6T design in the system if users have to expand the current system.
● Excellent signal integrity. There is low latency and better networking support. Strong signal transmission helps transmit data without any full stops.
Many industries deploy OSFP transceivers to transmit data. The applications are:
● Hyperscale data centers (Meta, Google, Microsoft)
● AI/ML infrastructure requiring non-blocking fabrics
● Intra-rack or inter-rack connections
● Core spine-leaf architectures
QSFP-DD (Quad Small Form Factor Pluggable – Double Density) is derived from the QSFP interface and maintains the integrity of the network. With backward compatibility, this system offers all the features in a compact space. If the space is your concern, QSFP-DD is the one you should opt for.
Here are the technical specifications of this system.
● Electrical lanes: 8 x 50Gbps PAM4
● Dimensions: ~89.4 mm x 18.35 mm x 8.5 mm
● Interface: Supports MPO, LC, and CS connectors
● Power consumption: Typically around 12W (can go up to 14W with enhanced cooling)
● Reach: Similar to OSFP—100m to 10km depending on module type
Due to the compact space, there are several benefits of deploying this system. Here is the list.
● Smaller footprints. Do you use smaller spaces? QSFP-DD closes more in a small space and, therefore, saves the day for the users.
● Backward Compatibility. This system is backward compatible with the 100G or 200G QSFP-based systems. Therefore, you can install it in older systems and cut costs on installing a new system.
● Industry adoption. Most vendors have adopted the QSFP-DD technology for its space-saving and cheaper solutions. Moreover, the versatility of the system makes its adoption on larger scales possible.
● Versatility. QSFP-DD works with several devices and tools. It can work with DACs (direct attach copper), AOCs (active optical cables), and breakout cables.
QSFP-DD is not a standard transceiver if you have plans for the expansion of your network. However, it is suitable for various applications.
Here is the list.
● Enterprise data centers transitioning from 100G to 400G
● Cloud edge computing nodes
● Top-of-rack switches
● Upgrade scenarios where legacy QSFP compatibility is required
● Environments with tight space constraints
Feature | OSFP | QSFP-DD |
Form Factor Size | Larger (better thermal management) | Smaller (better density) |
Port Density | Lower per RU | Higher per RU |
Power Consumption | Higher (up to 18W) | Lower (typically up to 14W) |
Thermal Management | Superior airflow and cooling | Requires enhanced cooling solutions |
Backward Compatibility | Not compatible with QSFP modules | Backward compatible with QSFP |
Common Use Cases | Hyperscale, AI, HPC | Enterprise, cloud edge, TOR switches |
Vendor Adoption | Growing but fewer switch options | Widespread across switch platforms |
Scalability | 800G/1.6T readiness | 800G possible with advanced modules |
The selection of an optical fiber system is not a walk in the park. For the selection of the correct transceiver, you should consider the following points.
How much space do you have? OSFP consumes more space and can't offer compactness. If you have a data center with multiple ports and a compact design, QSFP-DD is the ideal choice. It can better manage the port density and consume less space. Also, you enjoy better adherence to the existing system.
Data transmission through the fiber optic ground wires can produce heat. You need a transceiver that can manage all the integrated devices without getting heated much.
In that case, OSFP is a better choice. Do you know why? It has superior cooling properties and can handle heat excellently. Therefore, you manage the system without any extra heat.
Do you want to run your 400G upgrades with the 100G or older systems? OSFP is not the ideal choice because it doesn't provide better backward compatibility.
So, what should you choose in this case? QSFP-DD is a safer and better option because of its backward compatibility features. There is no need to update the system when working with this transceiver.
Application scale matters a lot. For some applications, OSFP 400G is better. In some other applications, you can find QSFP-DD to be more suitable.
Here is a brief overview.
● Choose OSFP for hyper-scale data centers, AI/ML networks, or HPC clusters
● Opt for QSFP-DD in enterprise deployments, cloud edge data centers, or when upgrading legacy QSFP equipment.
Do you have plans for the expansion of the network and technology? Get on the right track with the correct type of transceiver. For the anticipated increase, you should choose the OSFP because it is easier to scale. You can take 800G or 1.6T with this system. On the other hand, QSFP-DD can't go beyond the 400G limits, especially in the case of advanced modulation.
OSFP is the best choice in the following cases.
● Handles higher power (up to 18W).
● Best for AI, HPC, and hyperscale use.
● Ready for 800G/1.6T upgrades.
● Superior heat dissipation.
● Ideal for new, non-QSFP setups
QSFP-DD is the best choice in the following cases.
● Higher port density.
● QSFP is backward compatible.
● Widely supported by vendors.
● Lower power usage.
● Great for enterprise and edge
As a trusted supplier, 400G transceiver solutions are available at SDGI Cables. We offer a wide range of products and customization.
Here is much more to know about our products and their quality.
SDGI Cable offers a range of OSFP 400G and QSFP-DD.
● OSFP SR8 / DR8 / FR4 / LR4
● QSFP-DD SR8 / DR4 / FR4 / LR4
● 400G ZR for DCI (Data Center Interconnect) over extended ranges
● AOC/DAC cables for short-range, low-latency connectivity
If you live in remote areas and want to customize the products based on your needs, please tell us your requirements. We offer features depending on what you need.
Here is more to know.
● Connector types: MPO, LC, duplex, CS
● Fiber types: Singlemode (OS2), Multimode (OM3/OM4
Our team comprises the experts and provides all the technical support you need. The quality assurance and premium support puzzle out all your confusion.
Plus, we apply a quality control system during production. So, get a high-end product at a cheaper price.
All the products we offer comply with the international rules and regulations. You can get products that are 100% compliant with:
● IEEE 802.3bs (400G Ethernet), MSA standards
● ISO 9001-certified manufacturing
● RoHS and CE compliant for global deployment
That means they are already tested for the international protocols.
The evolution of industries to 400G is not a fashion but a necessity of time. OSFP and QSFP-DD are reliable and support this technology, but they have a few differences. Therefore, you can't use both of them simultaneously.
The usage scenarios include:
● Choose OSFP for higher thermal headroom, future scalability, or specialized high-power optics.
● Choose QSFP-DD for port density, backward compatibility, and widespread ecosystem support.
Do you want expert advice? SDGI has all the experts gathered in one place to resolve all your queries. Contact SDGI Cable for professional advice and product inquiries.
