What is the difference between CFP and QSFP？

CFP (C Form-Factor Pluggable) and QSFP (Quad Small Form-factor Pluggable) are both types of optical transceiver modules used in high-speed networking applications, but they differ in terms of their size, speed, and form factor.

1. Form Factor: - CFP: CFP modules have a larger form factor, which means they are physically bigger in size compared to QSFP modules. - QSFP: QSFP modules have a smaller form factor, making them more compact and space-efficient.

2. Speed and Port Density: - CFP: CFP modules support higher data rates and are designed for higher port density applications. - QSFP: QSFP modules also support high data rates but are typically used in applications with lower port density.

3. Applications: - CFP: CFP modules are often used in core networking and long-haul transmission applications where higher port density and data rates are required. - QSFP: QSFP modules are commonly used in data center and short-haul applications where space efficiency and lower port density are important.

In summary, the main differences between CFP and QSFP lie in their size, speed, and intended applications. CFP modules are larger, support higher data rates, and are used in higher port density applications, while QSFP modules are smaller, support high data rates, and are used in applications with lower port density.

Form factor & connectors

The term "form factor" refers to the standardized size and shape (or footprint ) of the optic, but other design features also help create each standard's definition. While there are many different transceiver form factors to consider, a few standards are more universal than the others.

Which you need is primarily determined by what form factors are compatible in the switch or router the optic is to be plugged in to, so it is always good to check what your system accepts.

AddOn's SFP-10G-SR-S-AO Cisco Compatible 1G SFP+ 40km LC Transceiver

Without the right form factor for your network environment, the optic may not fit into your switch or router at all. If it does connect, it may have impaired performance.

Can I use 100G QSFP28 port based with 40G QSFP+ transceiver?

Most Switches, Network Packet Broker (NPB), and other Network Element allow the use of 40G QSFP+ optics within QSFP28 slot to support 10G using fanout/Breakout cable or 40G Multimode straight conectivity using MTP to MTP fiber cable.

SFP vs SFP+ vs XFP vs QSFP+ vs CFP vs QSFP28 Differences

Through the above definitions of each type of fiber optic transceiver module, you may have a further understanding of them. Now, we are comparing these transeiver one by one.

SFP vs SFP+ (SFP+ vs SFP): Simple to understand, SFP+ is an updated vision of SFP. SFP usually support 1.25Gbit/s to 4.25 Gbit/s while SFP+ supports data rates up to 10 Gbit/s. When it comes to SFP vs SFP+, they have the same size and appearance, but in a different standard which SFP is based on IEEE802.3 and SFF-8472.

SFP+ vs XFP (XFP vs SFP+): In comparison to earlier XFP modules, SFP+ modules leave more circuitry to be implemented on the host board instead of inside the module. The size of SFP+ is smaller than XFP, thus it moves some functions to motherboard, including signal modulation function, MAC, CDR and EDC. XFP is based on the standard of XFP MSA while SFP+ is compliance with the protocol of IEEE 802.3ae, SFF-8431, SFF-8432.

SFP+ vs QSFP+: QSFP+ has four-channel SFP+ interfaces which can transfer rates up to 40Gbps. And of course, they have different standards.

CFP vs QSFP+: QSFP+ (Quad Small Form-Factor Pluggable Plus) modules offer customers a wide variety of high-density 40 Gigabit Ethernet. The CFP is a hot-pluggable transceiver module form factor that supports a wide range of 40Gb/s and 100Gb/s applications such as 40G and 100G Ethernet.