RJ45 Port Switch VS SFP Port Switch

NADDOD Edward Jan 14, 2023

Both RJ45 port switches and SFP port switches can be used for gigabit network transmission, so how to choose when building a gigabit link? Is it a fiber switch with SFP port or a switch with RJ45 electrical port?

RJ45 Electrical Port and SFP port Selection Principles

First, both ports are used to transmit gigabit rates. However, when the transmission distance is greater than 100 meters, SFP port and optical module should be selected instead of RJ45 electrical port and copper cable.

When the transmission distance is less than 100 meters, in the choice of the two, the following aspects need to be considered.

Security: In a more harsh environment, optical modules will be safer than copper wire. Because the electrical signal in the copper wire is prone to fire or lightning.

Reliability: Because the basic component of optical fiber is quartz, which only transmits light and does not conduct electricity, the optical signal transmitted in it is not affected by electromagnetic fields, so optical fiber transmission has a strong resistance to electromagnetic interference and industrial interference. Because of this, the signal transmitted in the optical fiber is not easy to be eavesdropped, and therefore conducive to confidentiality. The copper wire of the RJ45 interface tends to generate crosstalk in the current transmission - often called electromagnetic interference, which refers to electrical equipment, such as some high-voltage lines, will cause interference to other electronic products in the vicinity of the work. Therefore, fiber optics has an advantage over copper wire in this regard.

Network upgrade needs: If there is a subsequent demand for bandwidth upgrade, fiber optic patch cable is more advantageous than super Category 5 / Category 6 RJ45 interface network cable.

Cost: the actual operating rate of the two is the same, but the copper port will be a more cost-effective choice, because copper wire is cheap, while the optical port needs to be used with optical modules and fiber optic patch cords, which will be another overhead.

RJ45 Electrical Port VS SFP port: Gigabit Communication Case Practice

This section will use case studies to explain how RJ45 electrical and SFP ports are used in real-world situations.

RJ45 Electrical Port VS SFP port: Establishing Communication Between Two Buildings

Case Description: Two Gigabit switches are needed to establish communication between two buildings 300ft apart. Choose optical or electrical port switch?


Case Study: Electric-port switches can save cost. However, in a practical situation, there are many factors to consider. First, if the power supply systems of the two buildings are independent of each other, then copper wire connections can lead to ground loops. Secondly, copper wires may also be struck by lightning. In both of the above cases, fiber is recommended, and if conditions do not allow, a wireless solution is also good.

RJ45 Electrical Port VS SFP port: Inter-rack Connection

Case description: To connect devices in the same rack, it may seem that copper wire is more suitable, but it is not. So why choose the more costly optical fiber?

Case Study: This case describes the choice of gigabit devices on the same rack, optical port devices are better because copper port devices generate electromagnetic interference when connected using network cables. In addition, the optical port is also more advantageous in terms of power consumption, if the link is up to 100, SFP port compared to the electrical port, you can greatly save power consumption.