Ethernet
Contents
Introduction 1
Ethernet DTE and DCE 1
The Fundamentals of an Ethernet LAN, Explained 1
What You Need in an Ethernet LAN 2
How Ethernet Works 2
Types of Ethernet Cables 3
Advantages and Disadvantages of Ethernet Cables 5
Alternatives to Ethernet Cables for Computer Networking 6
References: 6
Introduction
Ethernet is a family of computer networking technologies commonly used in local area networks (LAN), metropolitan area networks (MAN) and wide area networks (WAN). It was commercially introduced in 1980 and first standardized in 1983 as IEEE 802.3, and has since been refined to support higher bit rates and longer link distances. Over time, Ethernet has largely replaced competing wired LAN technologies such as Token Ring, FDDI and ARCNET.
The original 10BASE5 Ethernet uses coaxial cable as a shared medium, while the newer Ethernet variants use twisted pair and fiber optic links in conjunction with switches. Over the course of its history, Ethernet data transfer rates have been increased from the original 2.94 megabits per second (Mbit/s) to the latest 400 gigabits per second (Gbit/s). The Ethernet standards comprise several wiring and signaling variants of the OSI physical layer in use with Ethernet.
Systems communicating over Ethernet divide a stream of data into shorter pieces called frames. Each frame contains source and destination addresses, and error-checking data so that damaged frames can be detected and discarded; most often, higher-layer protocols trigger retransmission of lost frames. As per the OSI model, Ethernet provides services up to and including the data link layer.
Since its commercial release, Ethernet has retained a good degree of backward compatibility. Features such as the 48-bit MAC address and Ethernet frame format have influenced other networking protocols. The primary alternative for some uses of contemporary LANs is Wi-Fi, a wireless protocol standardized as IEEE 802.11.
Ethernet DTE and DCE
All nodes on an Ethernet network are either DTE (Data Terminal Equipment) or DCE (Data Communications Equipment).
Ethernet DTE are devices such as computers and printers that are trying to communicate on the Ethernet network.
Ethernet DCE are devices such as switches and routers that are trying to help other devices communicate on the Ethernet network.
The Fundamentals of an Ethernet LAN, Explained
Ethernet is the technology that is most commonly used in wired local area networks (LANs). A LAN is a network of computers and other electronic devices that covers a small area such as a room, office, or building. It is used in contrast to a wide area network (WAN), which spans much larger geographical areas. Ethernet is a network protocol that controls how data is transmitted over a LAN. Technically it is referred to as the IEEE 802.3 protocol. The protocol has evolved and improved over time to transfer data at the speed of a gigabit per second.
Many people have used Ethernet technology their whole lives without knowing it. It is most likely that any wired network in your office, at the bank, and at home is an Ethernet LAN. Most desktop and laptop computers come with an integrated Ethernet card inside so they are ready to connect to an Ethernet LAN.
What You Need in an Ethernet LAN
To set up a wired Ethernet LAN, you need the following:
· Computers and devices to connect. Ethernet connects any computer or other electronic devices to its network as long as the device has an Ethernet adapter or network card.
· Network interface cards in the devices. A network interface card is either integrated into the motherboard of the computer or installed separately in the device. You also have USB versions of Ethernet cards such as external dongles. An Ethernet card is known as a network card. It has ports where you can connect cables. There are normally two ports, one for an RJ-45 jack that connects unshielded twisted pair (UTP) cables and one for a coaxial jack.
· A router, hub or gateway to connect your devices. A hub is a device that acts as a connecting point between devices on a network. It consists of several RJ-45 ports to which you plug the cables.
· Cables. UTP cables are commonly used in Ethernet LANs. This is the same type of cable used for landline telephone sets, but fatter, with eight twisted pairs of wires of different colors inside. The end is crimped with an RJ-45 jack, which is a larger version of the RJ-11 jacks that plug into your landline phone. When the Ethernet spans beyond a room to a greater distance, coaxial cable is used. This is the same cable with a round single-core jack you use for a TV.
· Software to manage the network. Modern operating systems like recent versions of Windows, Linux and MacOS are more than sufficient to manage Ethernet LANs. Third-party software that gives more features and better control is available.
How Ethernet Works
Ethernet requires technical knowledge in computer science to understand the mechanism behind the Ethernet protocol fully. Here is a simple explanation: When a machine on the network wants to send data to another, it senses the carrier, which is the main wire connecting all the devices. If it is free, meaning no one is sending anything, it sends the data packet on the network, and all other devices check the packet to see whether they are the recipient. The recipient consumes the packet. If there is already a packet on the highway, the device that wants to send holds back for some thousandths of a second to try again until it can send.
Types of Ethernet Cables
As the standard cables that are commonly used to connect a modem to a router, and to connect a router to a computer’s network interface card (NIC), Ethernet cables have many different categories, such as Category 3, Category 5, Category 5e, Category 6, Category 6a, and Category 7. These types of Ethernet Cables have been developed, and each category has different specifications as far as shielding from electromagnetic interference, data transmission speed, and the possible bandwidth frequency range required to achieve that speed. It may be hard to decide which one you need while looking at all the available options for Ethernet cabling. Actually, the category of cable is usually clearly printed on the cable’s sheath, so there can be no doubt as to the type of cable being used. But do you know about the main differences between these categories of Ethernet cable? So in the following part we will tell about the main features of each type of Ethernet Cable.
Category 3
Category 3 Ethernet cable, also known as Cat 3 or station wire, is one of the oldest forms of Ethernet cable still in use today. It is an unshielded twisted pair (UTP) cable that is capable of carrying 10 megabits per second (Mbps) of data or voice transmissions. Its maximum possible bandwidth is 16 MHz. Cat 3 cable reached the peak of its popularity in the early 1990s, as it was then the industry standard for computer networks. With the debut of the faster Category 5 cable, however, Cat 3 fell out of favor. It still can be seen in use in two-line telephone systems and older 10BASE-T Ethernet installations.
Category 5
Category 5 (Cat 5) Ethernet cable is the successor to the earlier Category 3. Like Cat 3, it is a UTP cable, but it is able to carry data at a higher transfer rate. Cat 5 cables introduced the 10/100Mbps speed to the Ethernet, which means that the cables can support either 10 Mbps or 100 Mbps speeds. A 100 Mbps speed is also known as Fast Ethernet, and Cat 5 cables were the first Fast Ethernet-capable cables to be introduced. They also can be used for telephone signals and video, in addition to Ethernet data. This category has been superseded by the newer Category 5e cables.
Category 5e
The Category 5e standard is an enhanced version of Cat 5 cable, which is optimized to reduce crosstalk, or the unwanted transmission of signals between data channels. This category works for 10/100 Mbps and 1000 Mbps (Gigabit) Ethernet, and it has become the most widely used category of Ethernet cable available on the market. While Cat 5 is common in existing installations, Cat 5e has completely replaced it in new installations. While both Cat 5 and Cat 5e cables contain four twisted pairs of wires, Cat 5 only utilizes two of these pairs for Fast Ethernet, while Cat 5e uses all four, enabling Gigabit Ethernet speeds. Bandwidth is also increased with Cat 5e cables, which can support a maximum bandwidth of 100 MHz. Cat 5e cables are backward compatible with Cat 5 cables, and can be used in any modern network installation.
Category 6
One of the major differences between Category 5e and the newer Category 6 is in transmission performance. While Cat 5e cables can handle Gigabit Ethernet speeds, Cat 6 cables are certified to handle Gigabit Ethernet with a bandwidth of up to 250 MHz. Cat 6 cables have several improvements, including better insulation and thinner wires, that provide a higher signal-to-noise ratio, and are better suited for environments in which there may be higher electromagnetic interference. Some Cat 6 cables are available in shielded twisted pair (STP) forms or UTP forms. However, for most applications, Cat 5e cable is adequate for gigabit Ethernet, and it is much less expensive than Cat 6 cable. Cat 6 cable is also backwards compatible with Cat 5 and 5e cables.
Category 6a
Category 6a cable, or augmented Category 6 cable, improves upon the basic Cat 6 cable by allowing 10,000 Mbps data transmission rates and effectively doubling the maximum bandwidth to 500 MHz. Category 6a cables are usually available in STP form, and, as a result, must have specialized connectors that ground the cable.
Category 7
Category 7 cable, also known as Class F, is a fully shielded cable that supports speeds of up to 10 Gbps (10,000 Mbps) and bandwidths of up to 600 Mhz. Cat 7 cables consist of a screened, shielded twisted pair (SSTP) of wires, and the layers of insulation and shielding contained within them are even more extensive than that of Cat 6 cables. Because of this shielding, they are thicker, more bulky, and more difficult to bend. Additionally, each of the shielding layers must be grounded, or else performance may be reduced to the point that there will be no improvement over Cat 6, and performance may be worse than Cat 5. For this reason, it’s very important to understand the type of connectors at the ends of a Cat 7 cable.
The following table summarizes the most common types of Ethernet cables, including their maximum data transmission speeds and maximum bandwidths.
Cable Type
Maximum Data Transmission Speed
Maximum Bandwidth
Category 3
UTP
10 Mbps
16 MHz
Category 5
UTP
10/100 Mbps
100 MHz
Category 5 e
UTP
1000 Mbps
100 MHz
Category 6
UTP or STP
1000 Mbps
250 MHz
Category 6 a
STP
10,000 Mbps
500 MHz
Category 7
SSTP
10,000 Mbps
600 MHz
Ethernet cables are manufactured in two basic forms called solid and stranded. Solid Ethernet cables offer slightly better performance and improved protection against electrical interference. They're also more commonly used on business networks, wiring inside office walls, or under lab floors to fixed locations
Stranded Ethernet cables are less prone to physical cracks and breaks, making them more suitable for travelers or in home networking setups.
Advantages and Disadvantages of Ethernet Cables
Advantages:
1. Reliability: Very reliable
2. Speed: 100 Mbps for Fast Ethernet (100BaseT), 1000 Mbps for Gigabit Ethernet (Other factors such as networked computer CPU speed, OS and frame size may affect performance)
3. Data Security: Use common firewalls for data security
Disadvantages:
1. Only for short distance networks - can only reach around 350 feet without daisy-chaining switches together
2. Ethernet cable runs, hubs, routers and switches connect the networked computers adding to installation costs
3. 10 Mbps for traditional Ethernet (10BaseT)
4. Limited mobility
5. Crosstalk with longer cable runs
Alternatives to Ethernet Cables for Computer Networking
Wireless technologies like Wi-Fi and Bluetooth have replaced Ethernet on many home and business networks. These wireless technologies are especially advantageous if you'd otherwise run cable outside or in locations with heightened risk of wire damage.
References:
1. https://www.lifewire.com/what-is-ethernet-3426740
2. https://www.lifewire.com/what-is-an-ethernet-cable-817548
3. https://en.wikipedia.org/wiki/Ethernet
4. http://ciscorouterswitch.over-blog.com/search/ethernet/
5. https://www.quora.com/What-are-the-advantages-and-disadvantages-of-ethernet-cable
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