RJ45 vs SFP Port: Which is better for network switches connection

The world of networking is one of continual evolution, bringing with it new technologies, protocols, and connectivity options. Two key players in this arena are the RJ45 and the Small Form-factor Pluggable (SFP) port, each boasting its unique features, benefits, and applications. So how does one decide between the two? In this article, we will explore the RJ45 and SFP ports, comparing their performance in 1G connections, their applications, and other crucial aspects such as cabling system, transmission distance, power consumption, cost, and network upgrade potential.


What is an RJ45 Port?

RJ45, also known as Registered Jack 45, is a standard type of physical connector for Ethernet networks. It supports network speeds up to 10 Gigabits per second (Gbps) over Cat5e, Cat6, Cat6a, and Cat7 copper cables, with a maximum distance limitation of 100 meters. Widely used for Local Area Network (LAN) connections, the RJ45 port is well-suited for short-range network applications such as connecting computers, routers, and switches within a single building or campus.

What is an SFP Port?

The SFP port, standing for Small Form-factor Pluggable, is a hot-pluggable input/output device that plugs into a Gigabit Ethernet port or slot, linking the port with the network. SFP modules are primarily used to support longer distance, higher speed network connections, such as 550m, 10km, 40km. They can handle different types of communication such as fiber optics and ethernet, providing flexibility in terms of the type of physical connection that can be used.

RJ45 vs SFP Port in 1G Connection

The decision between RJ45 and SFP can often come down to the specific needs of a 1G connection. Let us find the diffrerences.

Cabling System

RJ45 uses copper-based cables like Cat5e, Cat6, Cat6a, and Cat7. Copper cables are relatively cheap and readily available, making them a popular choice for short-distance connections. On the other hand, SFP uses fiber optic cables. Fiber optics provide higher bandwidth, allowing for data transmission over much longer distances than copper cables. 

Nowadays, copper cables are more expensive, but fiber optic cables require careful handling as they are more delicate. One significant benefit of fiber optic cable is its lightweight nature. Each meter of this cable weighs in at just 0.05kg, a stark contrast to the heftier network cable, which tips the scales at 0.5kg per meter. The planning process for a network cable wiring system must take into account factors such as load-bearing capacity and flexibility. Fiber optic cables have an edge in this regard, with a minimum bending radius that is considerably less than that of an excess network cable.

Transmission Distance

While both RJ45 and SFP are capable of handling 1G connections, their reach varies significantly. RJ45 ports are limited to a maximum of 100 meters due to the use of copper cables; whatever you choose cat6a, cat7, the maximum distance doesn’t change. In contrast, SFP ports, through the use of single-mode or multimode fiber optic cables, can extend the transmission distance to kilometers or even 100 kilometers, greatly outperforming the RJ45 in terms of reach.

Power Consumption

RJ45 ports generally consume less power than SFP ports. Copper-based connections are more energy-efficient, and thus more cost-effective for short distances. Conversely, SFP ports, due to their use of optics, consume more power. However, they provide better performance over long distances, which can justify the increased power consumption.


Cost is a crucial consideration in any network infrastructure decision. Generally, RJ45 ports devices are cheaper than SFP ports devices. However, it’s essential to factor in other costs such as power consumption and maintenance over the lifespan of the network, which might make SFP a more cost-effective choice for long-haul connections. Besides, the  ethernet cable is much expensive than fiber optic cable of the same length.

Network Upgrade

In terms of network upgrade potential, SFP ports hold an advantage. With RJ45, you are confined to the limitations of copper cabling. However, with SFP ports, you can easily upgrade from multimode to single-mode fiber, or even to higher speed SFP+ or SFP28 modules, allowing for significant scalability and future-proofing of your network infrastructure.

RJ45 vs SFP Port Application

Long Haul and Metropolitan Application

In long-haul and metropolitan applications where distance and high-speed transmission are paramount, SFP ports are generally the better option. They offer superior performance over long distances thanks to the use of fiber optic cables. SFP is also the go-to choice for most Service Provider and Data Center networks due to its higher capacity, longer reach, and upgradability.

In-rack Application

For in-rack or short-range applications, such as connections within a data center rack or between devices in the same floor, RJ45 ports are typically the preferred choice. They provide sufficient speed and performance for these shorter distances, and their lower cost and power consumption make them a cost-effective solution.


The choice between RJ45 and SFP ports depends largely on the specific network requirements, considering factors like distance, speed, cost, power consumption, and future upgradability. RJ45 may be the better choice for short-range, cost-sensitive applications, while SFP is more suitable for long-range, high-speed, and upgrade-prone scenarios. Understanding the strengths and limitations of each can help network architects make the right choice for their specific needs.

Fiber Optic Cable Types Comparison: Single Mode vs Multimode Fiber Cable

Fiber optic cables, also known as optical cables, are at the forefront of the telecommunications industry, providing unparalleled speed and transmission distance compared to traditional copper cables. Their widespread application in diverse fields, from internet service providers to medical scanning devices, has amplified the significance of understanding the difference between single mode fiber (SMF) and multimode fiber (MMF) optic cable types. This article will delve into the construction, distance capabilities, cost, color, and bandwidth of both cable types to elucidate the differences and provide a comprehensive comparison.

 Overview of Single Mode Fiber Cable and Multimode Fiber Optic Cable

The basic distinction between SMF and MMF arises from their core diameter and mode of propagation. The SMF, with a smaller core diameter, allows the propagation of a single light mode, while MMF, having a larger core, supports the transmission of multiple light modes simultaneously.

fiber optic cable

Core Diameter

The core diameter is integral to the performance of fiber optic cables. The SMF has a smaller core diameter, typically 9 micrometers, ensuring that only a single light mode can travel through it. This results in lower data loss and greater transmission distance. In contrast, MMF has a larger core diameter, usually 50 or 62.5 micrometers, allowing multiple light modes to propagate. This causes more dispersion and limits the transmission distance.

The size of the fiber core impacts the attenuation or signal loss in fiber optic cables. Larger core diameters, as seen in MMF, often result in higher attenuation due to numerous light reflections, whereas the narrower core of SMF enables minimal reflections, leading to lower attenuation. Let’s look at a comparison table that provides clarity on this aspect:

Fiber TypeCore Diameter (microns)Attenuation at 1310nm (dB/km)Attenuation at 1550nm (dB/km)Attenuation at 850nm (dB/km)Attenuation at 1300nm (dB/km)
9/125 Single Mode Fiber90.40.25N/AN/A
50/125 OM3 Multimode Fiber50N/AN/A3.01.0

Please note, the higher attenuation in MMF at both 850nm and 1300nm wavelengths is due to its larger core diameter, which allows multiple light paths, thus causing more signal loss due to scattering and dispersion. On the other hand, the SMF’s narrow core allows a single light path, resulting in significantly less signal loss at its operating wavelengths (1310nm and 1550nm).

Wavelength & Transceiver

The operating wavelength and associated transceivers for SMF and MMF also differ significantly. SMF operates typically at 1310 nm and 1550 nm wavelengths, paired with longer-range transceivers. MMF operates at shorter wavelengths like 850 nm and 1300 nm, using shorter distance transceivers.

Cable Bandwidth

Bandwidth, a measure of data transfer capacity, also sets SMF and MMF apart. Due to its single-mode propagation, SMF has a virtually unlimited bandwidth, subject to equipment limitations. MMF, owing to its multi-mode propagation and dispersion, has a limited bandwidth, restricting its data transfer rate over long distances.

Single Mode vs Multimode Fiber Distance

The transmission distance of fiber optic cables is a critical consideration. OM1, OM2, OM3, OM4, and OM5 are different types of MMF with varying core diameters and bandwidths, offering different maximum transmission distances. Conversely, OS2 is a type of SMF with superior distance capabilities, making it ideal for long-range applications.

To gain a comprehensive understanding of the transmission distances associated with the various types of fiber optic cables, we’ll present a comparative table that includes OM1, OM2, OM3, OM4, OM5 (all types of MMF), and OS2 (SMF).

Fiber TypeMaximum Transmission Distance (at specific speed)
OM1 (MMF)Up to 275m at 1Gb, Up to 33m at 10Gb
OM2 (MMF)Up to 550m at 1Gb, Up to 82m at 10Gb
OM3 (MMF)Up to 300m at 10Gb, Up to 100m at 40/100Gb SR4
OM4 (MMF)Up to 550m at 10Gb, Up to 150m at 40/100Gb SR4
OM5 (MMF)Up to 550m at 10Gb, Up to 400m at 40/100Gb SR4
OS2 (SMF)Based on the transceiver, more than 1000+ km

Fiber Cost

The cost of using fiber optic cables varies significantly, especially when comparing different transceivers. The cost of QSFPTEK SFP-1G-SX, SFP-1G-LX, SFP-10G-SR, SFP-10G-LR, QSFP-40G-SR4, QSFP-40G-LR4, QSFP-100G-SR4, and QSFP-100G-LR4 can be quite different when used with SMF and MMF. Generally, MMF cables and associated equipment are cheaper than SMF due to their simpler manufacturing process and shorter transmission distance requirements.


In conclusion, the selection between single-mode and multimode fiber optic cables depends on the specific requirements of the application, considering factors such as transmission distance, cost, and bandwidth. For short-range, high-bandwidth applications, MMF may be a more cost-effective solution. Conversely, for long-distance transmission, where high data rates and minimal loss are crucial, SMF would be the preferred choice. Hence, an understanding of the differences between these types of fiber optic cables is indispensable for making an informed decision.

Introduce OS2 Single Mode Fiber

cable construction, optical fiber cables, single mode fibers, maximum transmission distance, coarse wavelength division multiplexing, low water peak fibers, os1 vs os2
Figure: ST/FC/LC/SC fiber optic cable

As we know, OM1, OM2, OM3, and OM4 are defined for multimode fiber. What about single mode? Typically, single-mode fiber is classified into OS1 and OS2. OS1 and OS2 are standards (specifications) for single-mode fiber optic cable. There are actually quite a few differences between an OS1-compliant cable and an OS2-compliant cable. So, here let’s know more about os2 fiber.

What Is Single Mode Optical Fiber?

Single Mode Fiber is also called Less Reflection Mode, because the diameter of its core is very less, due to which data is transmitted by a single ray of light. In this, having less reflection than other modes, the data is able to travel for a long distance, and at the same time, the amount of data loss is also very less.

Single-mode optical fiber can have a diameter in the range of 7-9 microns, depending on the type. The normalized parameter for single-mode optical fibers is the mode spot diameter, the value of which depends on the type of optical fiber and the operating wavelength and lies within 8-10 microns.

In accordance with the international standard ITU-T Rec. G. 652, the deviation of the mode spot diameter from its average value is not more than 10%.

LC UPC to LC UPC Duplex fiber optic cable
Figure: LC UPC to LC UPC Duplex fiber optic cable

What is os2 smf fiber?

The regulatory requirements for class OS2 single-mode optical fibers are specified in ITU-T G.652C and G.652D. Engineers were primarily interested in the 1360-1460 nm range – the attenuation peak was in this region.

But after they managed to get rid of it, it turned out that even a wider window, from about 1280 to 1625 nm, became technologically applicable.

By the way, do not be surprised if in some materials you find ranges from 1310 to 1625 nm, from 1270 to 1620 nm, or other combinations of values ​​- developments in this area are ongoing, the numbers may still be corrected. An example is data for OS2 singlemode cables offered by Siemon:

As you can see, the attenuation in Siemon single-mode OS2 cables is not only less than 0.4 dB / km, but in some areas, it is also lower than 0.3 dB / km.

In fact, many manufacturers already had fibers with such characteristics even before the official adoption of the requirements for OS2, but according to the standard, they could only be applied to the OS1 designation that was officially valid at that time.

As a designer and user, you will find the following table of distance limits to guarantee the performance of various network applications. The gigabit application is highlighted.

How OS2 Fiber works?

A laser infuses a high-data transmission single mode fiber-optic link with the light of a thin unearthly width. A long strand of glass fiber commonly spreads laser transmission with the utilization of wave division multiplexing (WDM), which divides announces various frequencies to build the transmission motion.

This further develops the transmission pace of single-mode over multimode fiber, up to multiple times the possible distance.

The single light wave in the tight center essentially kills mutilations from obstruction or loss of light. This creates the most elevated transmission speed from transmitter to beneficiary of any fiber.

It works paying little mind to electromagnetic obstruction (EMI) and limits snooping by taking out signal spillage. Light frequencies around 1,300 nm serve for brief distances and 1,500 nm serve significant distances.

A communicating laser diode conveys a light message down a solitary mode fiber-optic link. Light, unfit to stop, ricochet, departure, or turn around through a line of somewhat bigger breadth, such as ping pong balls, goes ahead through a center encompassed by a non-permeable cladding that is multiple times as thick.

The frequency moves consistently with the powerlessness to refract, reflect or disperse as hotness inside the wave. It has no place else to go, with the exception of assuming that it experiences exemplified fabricating imperfections or establishment or interfacing mistakes.

Signal heartbeats can go through regenerative or attenuators until they arrive at a beneficiary. There, a photodiode interprets the waveforms roughly 8,000 times each second, changing over them into electronic PC signals as computerized information and sound/video data.

It resembles perusing a whole 24-volume set of reference books in a single second.

In single-mode fiber-optic link, this type of low-misfortune, least request engendering can just work over a specific cutoff frequency.

This is known as the single-mode (SM) step-list. This implies that main the straight light pillar is chosen for single-mode transmission;

They don’t cross or skip at various rates in multimode wave proliferation, through the expansive center of the multimode fiber.

Various sorts of single-mode fiber-optic links incorporate cutoff or scattering moved fiber, non-zero scattering moved low water top fiber, and others. Otherwise called mono-mode or uni-mode fiber, it is fundamentally utilized for wide region organizations (WANs);

However, it has drawn in more consideration than neighborhood (LANs), which stretch out their range to more prominent distances in settings like a college or corporate grounds.

These significant expense links have restricting variables like bowing sweep, so cautious arranging ought to be done preceding establishment by a gifted professional.


Single-mode fiber optics cable is used for long distances, because the diameter of the glass fiber core is very small, due to which a single beam of light passes through and through which it travels a long distance.

The bandwidth of SMF cable is also higher than multi mode fiber optics, and the laser is used in it.

Single-mode fiber is more expensive because it requires precise calculations to pass the laser through a small space.


High Bandwidth:

The data transmission speed of optical fiber is much higher than that of copper cable, due to which a large amount of data is transmitted in a very short time.


Optical fiber is more secure than metal cable, because it has more security layers, and data is also transferred in the form of light. Due to which it is not so easy to tamper with the data, that is, it is a more secure way of data transmission.

Low Power Loss:

Power loss in optical fiber is negligible, due to which data is transmitted over long distances, and the speed of data also remains the same.

Electronic Isolation:

There is no risk of electrical short circuits in optical fiber as compared to copper cable because its parts are made of silica glass and plastic, which keeps it away from electrical hazards.


Expensive Cost:

Optical fiber cable is more expensive than metal cable, and the equipment used in its connection is also expensive compared to others.

Splicing Issue:

If ever a joint is to be installed or repaired between the wires, then it becomes very difficult, and for this Splicing Machine is used.

Expensive Installation:

Along with the equipment of optical fiber, its installation is also very expensive, and it requires trained people.