What is Ethernet?
Ethernet is a technology that connects wired local area networks (LANs) and enables the device to communicate with each other through a protocol which is the common network language. This LAN is a network of computers and other electronic devices which covers a small area in your places like in the office, house, room or building. Unlike LAN, wide area network (WAN) covers much larger geographical areas. Furthermore, Ethernet is a protocol that controls the processes on how the data is transmitted through LAN. It also indicates how the network devices can transmit and format data packets so that the other network devices in the same area network segment can be able to receive, process and recognize them.
Any other devices with access to a geographically localized network by using a cable such as with wire rather than a wireless connection most likely use Ethernet whether at home, office, or school. However, these physical cables have an only limited distance that they can totally stretch and carry enough signals through their durability. This is the reason why there are different types of Ethernet cables used to perform a particular task in a certain situation. The following are the different types of Ethernet cables:
Ethernet LAN can be considered to consist of two main elements:
- Interconnecting media: The media through which the signals transmit is very important, within the Ethernet network system it governs most of the properties that determine the speed at which the data may be transmitted. There are several options that may be used:
- Coaxial cable: This was one of the first types of interconnecting media to be used for Ethernet. Typically, the characteristic impedance was around 110 ohms and therefore the cables normally used for radio frequency applications were not applicable. This type of cabling is not widely used for Ethernet these days as it is expensive and difficult to install.
- Twisted Pair Cables: Two types of twisted pair may be used: Unshielded Twisted Pair (UTP) or a Shielded Twisted Pair (STP). Generally, the shielded types are better as they limit stray pickup more and therefore data errors are reduced. A variety of different cable types are available as the standard are always moving forwards.
- Fibre optic cable: Fibre optic cable is being used increasingly as it provides very high immunity to pickup and radiation as well as allowing very high data rates to be communicated.
- Network nodes: The network nodes are the points to and from which the communication takes place, mainly but not limited to:
- Computers: Today, most computers come with the capability for Ethernet connectivity. Most desktop computers are expected to work on a local area network, and this is almost universally Ethernet based. Today the Ethernet capability will be built into the motherboard of the computer, rather than using an optional plug in board. The physical connection is normally provided using an RJ45 style Ethernet connector.
- Routers, switches, and hubs: The other main elements on local area networks using Ethernet as the interface medium are routers, switches, and hubs. These devices enable the data to be routed around the data networks so that they can be sent and reach their relevant destinations.
- Miscellaneous devices: On any local area network there will be the need for a variety of devices apart from computers, routers, switches, etc. Items like printers, etc will be needed. These can be linked onto the network in a similar way to any computer.
A variety of different devices can be connected to local area networks using Ethernet technology. Many different types of device intended for use on local area networks will have Ethernet capability.
Ethernet Network Topologies
There are several network topologies that can be used for Ethernet communications. The actual form used will depend upon the requirements.
- Point to point: This is the simplest configuration as only two network units are used. In this simple structure the cable is known as the network link. Links of this nature are used to transport data from one place to another and where it is convenient to use Ethernet as the transport mechanism.
- Coaxial bus: This type of Ethernet network is rarely used these days. The systems used a coaxial cable where the network units were located along the length of the cable. The segment lengths were limited to a maximum of 500 metres, and it was possible to place up to 1024 DTEs along its length. Although this form of network topology is not installed these days, a very few legacy systems might just still be in use. In view of the way in which it operates, with several nodes on the same leg, the CSMA/CD anti-collision scheme is used.
- Star network: This type of Ethernet network has been the dominant topology since the early 1990s. It consists of a central network unit, which may be what is termed a multi-port repeater or hub, or a network switch.
All the connections to other nodes radiate out from this and are point to point links. It is this type of network topology that is used and extended. Connections tend to extend out from a central hub using a series of routers or switches to divert the data to the required end node.
Advantages and Disadvantages of Ethernet
Ethernet has many benefits for users, which is why it grew so popular. However, there are a few disadvantages as well.
- Relatively low cost
- Backward compatibility
- Generally resistant to noise
- Good data transfer quality
- Data security — common firewalls can be used.
- It is intended for smaller, shorter distance networks.
- Mobility is limited.
- Use of longer cables can create crosstalk.
- It does not work well with real-time or interactive applications.
- Increased traffic makes the Ethernet speed go down.
- Receivers do not acknowledge the reception of data packets.
- When troubleshooting, it is hard to trace which specific cable or node is causing the issue.
The following are the different types of Ethernet networks:
This is a type of Ethernet network that can transmit data at a rate of 100 Mbps through a twisted-pair cable or fiber-optic cable. The data can be transferred from 10 Mbps to 100 Mbps with no protocol translation or changes in the application and networking software.
This is a type of Ethernet network that has the capability to transfer data at a rate of 1000 Mbps based on a twisted-pair cable or fiber-optic cable. Among other types of Ethernet cable, this is the most popular one.
Categories of Ethernet Cables
When shopping for cables, you may notice they are always classified as “Cat-5,” “Cat6e,” or something similar. “Cat” simply stands for “Category.” The number that follows indicates the specification version supported by the cable.
A general rule of thumb is that higher numbers represent faster speeds and higher frequencies, measured in megahertz (MHz). As is the case with most technologies, newer cables typically support higher bandwidths, and therefore increased download speeds and faster connections.
Keep in mind that longer Ethernet cables have slower transmission speeds. This is why Ethernet cables tend to have two speed ratings, one at 10-30 meters and one at 100 meters: Since the 100-meter rating doesn’t matter outside of very large professional projects, we suggest just focusing on the 10-30 meter numbers.
Below, you can see the capabilities of each cable type (we’re skipping categories 1, 2, and 4, as they are not technically recognized as Ethernet standards and have no application today).
|Category||Shielding||Max Transmission Speeds||Max Bandwidth|
|Cat 3||Unshielded||10Mbps||16 MHz|
|Cat 5||Unshielded||10-100Mbps||100 MHz|
|Cat 5e||Unshielded||1,000Mbps – 1Gbps||100 MHz|
|Cat 6||Shielded or Unshielded||10Gbps up to 55 meters||250 MHz|
|Cat 6a||Shielded||10Gbps up to 55 meters||500 MHz|
|Cat 7||Shielded||100Gbps up to 15 meters||600 MHz|
|Cat 7a||Shielded||100Gbps up to 15 meters||1,000MHz|
|Cat 8||Shielded||40Gbps up to 30 meters||2,000MHz|
Cat 3 and Cat 5
Both Cat 3 and Cat 5 Ethernet cables are, at this point, obsolete. They are slow and discontinued.
The “e” in Cat 5e stands for “enhanced.” There are no physical differences between Cat 5 and Cat 5e cables. However, manufacturers build Cat 5e cables under more stringent testing standards to eliminate unwanted signal transfers between communication channels (crosstalk). Cat 5e is currently the most commonly used cable, mainly due to its low production cost and support for speeds faster than Cat 5 cables.
Cat 6 cables support higher bandwidths than Cat 5 and Cat 5e cables. They are tightly wound and usually outfitted with foil or braided shielding. Said shielding protects the twisted pairs of wires inside the Ethernet cable, which helps prevent crosstalk and noise interference. Cat 6 cables technically support speeds up to 10Gbps for up to 55 meters. That speed comes with a price, however, as Cat 6 cables are more expensive than Cat 5 and Cat 5e variants.
The “a” in Cat 6a stands for “augmented.” Cables based on this standard are a step up from Cat 6 versions by supporting twice the maximum bandwidth. They’re also capable of maintaining higher transmission speeds over longer cable lengths. Cat 6a cables come shielded, and their sheathing — which is thick enough to eliminate crosstalk — makes for a much denser, less flexible cable than Cat 6.
Cat 7 cables support higher bandwidths and significantly faster transmission speeds than Cat 6 cables by utilizing the newest widely available Ethernet technology. Cat 7 cables reach up to 100Gbps at a range of 15 meters making it one of the most capable categories of Ethernet cables. Cat 7 cables are always shielded and use a modified GigaGate45 connector, which is backward compatible with RJ45 Ethernet ports.
That modified GG45 connector is a proprietary component though, and while the backward compatibility helped a little, there are still issues with following previous Ethernet standards. This led to most manufacturers avoiding the Cat 7 standard, which is why it’s quite rare today. That difficulty led to the development of Cat 6a, and a lot of marketing confusion, since some sellers started referring to Cat 6a as the new Cat 7.