RJ45 port VS SFP port
Hello, everyone!
In today’s article, I will explain the difference between the RJ45 port and the SFP port. Sounds interesting, doesn’t it? Let’s see!
Network devices such as routers, switches, servers, OLTs, ONUs, etc. use RJ45 ports and SFP ports for communication. Network devices can have one or more RJ45 ports, and the same is true for SFP ports. What’s the difference? What is better? We will see that in the following text.
RJ45 port
An RJ45 port is a port on a network device (routers, switches, PCs, printers, etc.) that uses UTP cables (copper cables with 8 wires) with RJ45 connectors. RJ stands for Registered Jacket. RJ45 port is often called ethernet port or LAN port. This port is part of the device and cannot be replaced.
This type of port is exclusively used for the transmission of electrical signals. Data transfer speeds are limited to a maximum of 40 Gbps, which requires the use of UTP cat 8 at a distance of less than 30 m. Most often, RJ45 ports enable 100 Mbps or 1 Gbps. These ports support different categories of UTP cables – cat 5, cat 5e, cat 6, cat 6a, and cat 8.
SFP port
SFP is short for Small Form-factor Pluggable. It is a transceiver that can work with an electrical or optical signal. These are modules that can be replaced during the operation of the device – hot-swappable modules. SFPs are designed to support different communication standards (PON, SONET, Ethernet, etc.). The modules are not regulated by an official standard, therefore there is no universal SFPs. This leads to the fact that devices of a certain brand require appropriate SFPs (e.g. cisco devices require only cisco SFPs, it is not possible to use other brands).
There are a number of different types of SFPs, classified according to:
- type of signal (electrical or optical),
- transmission speed (FE, GE, 10 GE, 40 GE, 100 GE, etc.),
- encapsulation types:SFP. It is a commonly used optical module, which uses LC optical connectors,eSFP (enhanced SFP). It is an SFP with additional functions such as support for monitoring of voltage, bias current, optical power, and temperature (DDM – Digital Diagnostic Monitoring function),
SFP+. This type is usually used for higher data transfer rates,
XFP. X is the Roman numeral for 10, so this is a 10 Gbps SFP. Uses LC optical connectors,
QSFP+ (Quad SFP+). This type of SFP module is used for MPO/MTP optical connectors, which means that these optical modules are larger than previous SFPs. This type of module can achieve a data transfer rate of 100 Gbps when using 4 channels. And,
OSFP (Octal SFP). This type of optical module enables transmission speeds of up to 800 Gbps, using 8 channels.
- modes (single-mode or multimode optical fibers), etc.
SFP port VS RJ45 port
The comparison between the SFP port and RJ45 port can be seen in the following table.
| Features | SFP port | RJ45 port |
| Connection Types | Copper SFP – RJ45 Ethernet cables (cat 5, cat 5e, cat 6, …)
Optical SFP – Optical cable with SM or MM optical fibers |
RJ45 Ethernet cables (cat 5, cat 5e, cat 6, …) |
| Max Distance | Optical cable with MMF – about 550 – 600 m
Optical cable with SMF – about 150 km RJ45 Ethernet cable – max 100 m |
RJ45 Ethernet cable – max 100 m |
| Data Rate | 100 Mbps, 1 Gbps, 10 Gbps, 40 Gbps, 80 Gbps, 100 Gbps, and 800 Gbps | 100 Mbps, 1 Gbps, 10 Gbps, and 40 Gbps |
| Security | High security, they do not have the problem of catch on a fire/lightning | Low security, they can have the problem of catch on a fire/lightning |
| Reliability | High reliability, no electromagnetic interference | Low reliability, has problems with electromagnetic interference |
| Latency | Low latency when using fiber optic cables | Possible problem with latency, especially at longer distances |
| Power Consumption | Lower consumption compared to RJ45 ports | Higher consumption compared to SFP ports |
| Future Network Upgrade | It is possible to upgrade by replacing the SFP module | There is no upgrade option |
| Cost | The price is higher compared to RJ45 ports | The price is lower compared to SFP ports |
In the end, we can conclude that SFP ports are a much better solution than RJ45 ports. The only disadvantage of SFP ports is the higher price compared to RJ45 ports.
This was the most important information related to the RJ45 port VS SFP port. I hope you learned something new.
Thank you!