Transmission Media Used To Implement An Ethernet LAN

Early implementations of Ethernet LANs employed thick coaxial cable. In fact, it was a thick yellow coaxial cable - original recipe Ethernet cable. The cable was defined by the 10Base-5 standard. This implementation was called Thicknet. It could deliver a BER of 10-8. It supported a data rate of 10 MBPS. The maximum LAN cable segment length was 500 meters. The segment length is the maximum distance between data terminal equipment. These are attractive features.
The unfortunately, the thick coaxial cable is difficult to work with. As a result, the second wave of the implementation of the Ethernet LAN using thin coaxial cable. The cable was RG58 A/U coaxial cable - sometimes called Cheapernet. This cable is made from 10Base-2 standard. The implementation was called Thinnet. It supported a data rate of 10 MBPS. But, it had a BER somewhat degraded relative to Thicknet. The LAN cable segment length was reduced to the order of 185 meters.
Thinnet ultimately gave way to the replacement of coaxial cable with Unshielded twisted pair (UTP) cable. This is done through an interesting Ethernet LAN architecture combined with another local area network (LAN) flavor called StarLAN, the AT & T.
StarLAN was based on a telecommunications, telephone company, usually do for the enterprise to provide voice communications. The Transmission Medium a Telecom used in a facility for voice communications are shielded twisted pair (STP) cable. It provides voice communication within a facility and the external world connect all telephone, mobile phone, closet, or by telephone wiring closet. The distance from handset to telephone closet is relatively limited, maybe 250 meters. The StarLAN idea is the basic method of voice and use it to a local area network (LAN). The LAN stations would be connected through a closet. The existing UTP cable present in a facility for voice would be used for the LAN data traffic. There would be no need to install a new and separate Transmissioin Medium. Installation costs would be contained. Unfortunately, StarLAN only supported 1 MBPS. It has never left the ground.
However, in 1990 aspects of StarLAN were taken and merged with the Ethernet LAN architecture. This leads to a new Ethernet LAN based on UTP and 10Based-T standard definition. Based on this method, Ethernet UTP really start the market place.
Ethernet under the 10Base-T standard has a hub and spoke architecture. This is illustrated in Figure 1. The various data equipment units, radio, are connected to a central point called multi-point repeater or Hub. The connections are by UTP cable. This architecture does support the Broadcast Channel - Ethernet Bus. This is because all of the data equipment unit can be broadcast to all the other data units through the Hub. Likewise, all data equipment units can listen to the transmissions from all other data equipment units as they are received via the UTP cable connection to the Hub. The Hub takes the place of the telephone closet. The Hub may be strictly passive or it may perform signal restoration functions.

Figure 1: 10Base-T hub-and-spoke architecture
The illustration Figure 2 indicates how the 10Base-T topology may actually look in an office set-up at some facility. The data units are computer equipment here. One serves as the file server. The illustration shows what is usually referred to as a 10Base-T Work Group. It may serve one specific department in a company. By connecting together these work groups Ethernet LANs may be extended. This can be achieved by using local area network (LAN) connection Hub network elements called bridges, routers and switches. Description of their operations is beyond the focus of the present discussion.

Figure 2: Ethernet operating as a 10Base-T work group
But, let us get back to 10Base-T. It supports a data rate of 10 MBPS. It has a BER comparable to Thinnet. However, the LAN segment length is reduced even further. With 10Base-T LAN segment length is only 100m - a short distance, but distance, it is permissible to many data equipment standing in a typical business. However, it may be too short to others. This is a place, fiber optic cable can come to the rescue.
For the LAN market place 10Base-T was far from the last word. It led to the development of 100Base-T - Fast Ethernet. It is also based on using UTP cable for transmission medium. However, it supports a data rate of 100 MBPS over cable segments of 100 meters.Fast Ethernet, itself, is not the end of the road. Suppliers are starting to promote Giga Bit Ethernet which is capable of supporting 1 GBPS. However, we will stop at Fast Ethernet and the problem that both it and 10Base-T have the short cable segment of 100 meters.
It will be worth define two terms before continuing in discussing the characteristics of the Ethernet. These are 1) the network diameter, and 2) slot time.
The Network Diameter is simply the maximum end-to-end distance between data equipment users, stations, in an ethernet network. It is really what has been referred to above as the cable segment. The Network Diameter is the same for both 10Base-T and 100Base-T, 100 meters.
After a BIU has begun the transmission of a packet the Slot Time is the time interval that a BIU listens for the presence of a collision with an interfering packet. The Slot Time cannot be infinite. It is set for both the 10Base-T and 100Base-T Ethernet architectures. It is defined for both standards as the time duration of 512 bits. With a 10Base-T Ethernet network operating at 10 MBPS the Slot Time translates to 51.2msec. With a 100Base-T Ethernet network operating at 100 MBPS the Slot Time translates to 5.12msec.

How Much Do You Know About Ethernet Network

As you know, nowadays Ethernet is the most common network standards.But you may be confused what is Ethernet.Ethernet is a data link and physical layer protocol defined by the IEEE 802.3 specification. It comes in many flavors, defined by maximum bit rate, mode of transmission and physical transmission medium.
What Is The Background Of Ethernet?
In the early 1980s, Digital Equipment Corporation, Intel, and Xerox developed the Ethernet Local Area Networking format. This technology was soon accepted by the IEEE Committee, creating the 802.3 standard. This standard dictates the use of CSMA/CD (Carrier Sense Multiple Access with Collision Detection) as its accessing scheme. Networks use NIC (network interface card), hub, transceiver, converter, repeater & switch, as well as different types of transmission medias for carrying signals.
A variety of Ethernet types have come and gone over the years, such as the following:
10BASE5 (Thicknet)
10BASE2 (Thinnet)
10BASE-FL
10BASE-T
In the mid 1990s, 100BASE-T (unshielded twisted-pair [UTP]) and 100BASE-FX (using fiber) were ubiquitous in the enterprise network, and they still are. Since the start of the millennium, enterprise networks have actively implemented Gigabit Ethernet, 1000BASE-T, in their network. The push for today is 10 Gbps in the core of the enterprise network.
What Is The Basic Ethernet Theory?
Ethernet Theory is a concept of how computers that are not physically connected should communicate with each other for the transmission of data.
1.Ethernet operational theory is quite easy to understand and a simple analogy is helpful to visualize the basics. Imagine a long hallway lined with offices. The hallway represents the physical network, the offices represent the attached stations. When an occupant wishes to speak to another occupant they would lean into the hallway, listen to make sure no one else is engaging in a conversation, then speak out addressing the desired recipient. All other occupants hear the conversation but ignore it knowing it is not directed to them.
2.Returning to our analogy, what if two or more occupants decide to speak at the same time? Naturally the overlapping voices would become garbled and indistinguishable. With Ethernet this is known as a collision. In the CSMA/CD method, CD stands for Collision Detection. If a collision is detected by a transmitting station(s) the rule states: stop transmitting immediately, transmit a jamming signal to inform all other stations to stop, then wait a random period (binary exponential backoff) and re-transmit. Unfortunately, as the quantity of stations increases so does the amount of collisions. This causes the average access time to increase proportionally. This is referred to in the industry as network congestion.
3. Fortunately, there are several ways to alleviate network congestion. One way is that the entire network can be upgraded to Fast Ethernet (100 Mbps) which represents a 10 fold increase in transmission speed. This, however requires upgrading of all components and can be rather expensive. Another approach is to add an Ethernet Switch.
Ethernet is an asynchronous Carrier Sense Multiple Access with Collision Detect (CSMA/CD) protocol/interface, with a payload size of 46-1500 octets. With data rates of tens to hundreds of megabits/second, it is generally not well suited for low-power applications. However, with ubiquitous deployment, internet connectivity, high data rates and limitless range expansibility, Ethernet can accommodate nearly all wired communications requirements. Common applications include:
1. Remote sensing and monitoring;
2. Remote command, control and firmware updating;
3. Bulk data transfer;
4. Live streaming audio, video and media;
5. Public data acquisition (date/time, stock quotes, news releases, etc.
As Ethernet network is widely used, many related products have occured, such as Ethernet cable, Ethernet Media Converter, Ethernet to serial converter and so on.