Computer Networking Essay, Research Paper
My senior project addresses the application, setup of local and wide area computer networks. To include mathematical calculations, education required and implementation, and history of computer networks. I found that even though entry into the field of computer networking can start with basic certifications such as; Cisco, Microsoft, and Novell. I found that there is an advantage to obtaining a degree in a computer field.
A network can be accomplished by having a group of computers connected by a network, so that as soon as data is entered into one computer, it can be immediately accessed by someone else on a connected computer, no matter how far away it may be. There is much work involved in this to include a lot of math, from equations to basic problems. Let first talk about mathematical aspects of setting up a network.
The first mathematical question in setting up a network is very basic. How many computers will be connected to this network and how many guest computers might come on at one time. An example of a guest computer is a laptop and connected it download information or access data. To find the answer to the question, simply count the desktop computers that will be connected and how many guest computers you expect to be connected at any one time.
The second mathematical problem is solved by using an algebraic equation. Let X = the amount of desktop computers that will always be connected, Y = the amount of guest computers that you expect to be connected at one time. So, the equation is: X+Y+1. The one added on the end of the equation is another guest file just to make sure you don’t fall short. So, this tells you how many files you need to create. The guest files will all be generically named so that all guests have the same access privileges, and all the permanent computers will have their own named file so they can have more personalized access privileges. These files are put on one main computer, the server. This controls all access privileges and any data put into a computer branching off from it in its network can be accessed from this all-powerful server computer. The previously stated problems are a large part of networking, although I couldn’t possibly tell about all the math involved without going on for another 5 or 6 pages or more. Those problems help with networking as far as setting up the network on the computer goes, but there is a whole another side.
The physical side of computer networking involves problems such as how many feet of cable are you going to need to connect the computers. Some large office buildings can have 1 mile of cable between their networked computers! If someone has 2 computers in their house, it may only involve 3 feet. The mathematical procedure is quite simple although it might take a while to complete. Just take out the old tape measure and start measuring. Don’t measure direct lines between the computers unless you want the cable stretching in a straight line between them. Chances are you will want it to run along a wall or around another object. Once the measuring is done, just add up the cable length and you have the answer to the problem.
If you have the money, you can afford faster networks than cable networks. These are more sophisticated, and I was lucky enough to get to try it last summer. It is called infrared data transfer (IDT). Instead of cables, you have an infrared connector hooked to your computer. Just aim the little infrared panel at the computer, it will trade information with infrared light. These infrared panels are usually about 1 square inch in size. This is much quicker and doesn’t involve annoying cables. You still need to gauge distance because there is a distance limit on how far apart they can be and still work. When you install them, your computer will ask questions such as how many lumens (measurement of brightness of light) you would like your panel to emit. It is not invisible to the naked eye but the amount of lumens it outputs is critical. If you have a fast computer, you might want more lumens so that your computer doesn’t crash because of lagging. If you have a slower computer you will want less lumens because other wise you will be sending data too fast for your computer and there will end up being a lot of gibberish that will mess up the receiving computer. The mathematical things that networking involves are almost endless depending on the situation.
When you look at net works in a small area like a single room, it is called a Local Area Network (commonly referred to as a LAN) and refers to a communication network with the following characteristics:
+ The network is confined to a small area typically a single building or a cluster of buildings.
+ The network consists of a shared transmission medium.
+ The data rate on the network is high, anywhere from 1Mbps to 100Mbps.
+ The devices on the network are peers. That is any device can initiate data exchange with any other device.
A LAN is an increasingly popular way for organizations large and small to get additional productivity gains from the use of personal computers. Large businesses, government agencies and universities have long realized the need for “collaborative computing” or people using their computers as a group. Today, more and more small businesses, local governments and schools are using the power of LANs to increase productivity and efficiency. It is beyond the scope of this paper to discuss the “enterprise wide” local and wide-area networks typically found in large organizations. Rather, this paper will concentrate on the designs, hardware and software typically found in smaller Workgroup LANs. The purpose here is to provide a base level of understanding of the terminology commonly used by networking professionals and how they interrelate.
Given that the concept Local Area Networking has been established for well over twenty years and given that LANs serve the computing requirements of a wide range of organizations, it follows that different types of LANs have been standardized at various times to suit specific computing needs. The organization that is responsible for establishing these standards is the Institute of Electrical and Electronic Engineers or the IEEE. This professional organization works with network providers and users to standardize product specifications so that hardware and software products from many different and companies that will work together on the LAN. Products that conform to these standardized specifications and therefore work together are considered to be Interoperation. Within the IEEE, various committees are set up to act as the standards setting bodies for different types of LANs. These LAN committees are designated by a number.
The two predominant types of standardized networking are Ethernet and Token Ring. Of the two, Ethernet networks are far more common than Token Ring networks. In general, Ethernet networks are designed for small and medium sized groups while Token Ring networks are best for larger groups. It is not uncommon with larger networks to have both types of networks, which are connected via a router or similar hardware device. The focus in this part of my paper on smaller networks, Ethernet will be covered in more detail than Token Ring.
Ethernet was developed in the mid 1970’s at the Xerox Palo Alto Research Center (PARC). Xerox did pioneering research in what are today very popular tools of personal computing like Graphical User Interfaces and mice. The IEEE standardized Ethernet by the 802.3 committee.
Ethernet is predominately used as a baseband transmission network, where all the network nodes share access to the network media on an equal basis. Baseband transmission means that data sent over the media uses the entire bandwidth of the media as opposed to broadband transmission where data takes only a segment of the media by dividing the media into electronic channels. Each Ethernet node has the capability to send data at the Ethernet standard speed of ten million bits (megabits) per second (10Mbps). Since the nodes are sharing the media, the actual data speed tends to be significantly less than 10Mbps in much the same way that the speed of a car on a in heavy traffic tends to be significantly less than the posted speed limit. Ethernet is based on a network access method called Carrier Sense Multiple Access with Collision Detection or CSMA/CD. On an Ethernet network, all nodes share the network much like an old party line telephone system. When nodes on an Ethernet network want to send data to another node, the node first senses (or listens to) the network to ascertain if there are other contending nodes already sending information. Any node can send information at any time provided that it first checks to see if the network is already in use. Once the data is sent, the node listens to the network to see if a collision occurred with data from another node that sent data at some time after the sending node last listened. If a collision occurs, the node simply re-sends the data until it successfully reaches its destination address. When there are a relatively small number of nodes on the network, collisions are fairly rare. As the number of nodes increases, the likelihood of collisions increases proportionately causing increased re-sends and generally decreasing network performance.
When the IEEE first standardized Ethernet, the type of media specified was thick coaxial cable, which allowed for a maximum cable length of 500 meters. Later, a second cable use of Ethernet was standardized based on thin coaxial cable that was less expensive and allowed segments of just under 200 meters. To differentiate between these two different cable uses, the designations 10BASE5 and 10BASE2 were developed for thick and thin coaxial cable respectively. The “10″ refers to the 10Mbps data transfer rate, “Base” refers to the fact that Ethernet is a baseband media access method and the “5″ or the “2″ refers to the maximum cable length between nodes.
With both 10BASE5 and 10BASE2, the nodes are arranged in a bus topology, meaning that they are connected one after another with a terminator on the last node on the bus. While this is a fairly simple design, has if a node fails on the bus, it effectively terminates the bus making media access impossible for nodes further down. Trouble shooting a bus type topology to find the problem node is time consuming and frustrating. To address this issue as well as provide for even less expensive media, a third use was developed using twisted pair cable and allowing for nodes up to 100 meters from the hub. This use was designated as 10BASE-T. Unlike 10BASE5 and 10BASE2, the 10BASE-T physical network design is a star topology with each node connecting not to the next node but to a central hub. If a node fails, the hub partitions that node from the rest of the LAN leaving the remaining nodes unaffected.
As it stands today, the popularity of Ethernet cable use are in order: 10BASE-T, 10BASE2 and 10BASE5. These use are not mutually exclusive meaning that an Ethernet LAN can, as an example have a 10BASE5 segment from the file server to the hub, a 10BASE2 segment of older nodes and a newer segment using the 10BASE-T topology. IEEE Implementation Interface (Connector) Type Cable
10BASE-T RJ-45 Twisted Pair
10BASE2 BNC Thin Coaxial
10BASE5 AUI Thick Coaxial
Token Ring is a network design that is based on a far more structured media access method. IBM developed Token Ring for larger LANs. The Token Ring IEEE designation is 802.5. With Token Ring, the network nodes are arranged in a ring pattern. LAN data, along with an electronic “token”, circle around the ring. Unlike Ethernet, a Token Ring node cannot send data at any time: it must first capture the token, which is constantly circling the ring. The node then attaches the data to be sent to the single token and sends it to its destination. In this manner, only one node can send at a time, eliminating the possibility of collisions. Historically, Token Ring hardware has been more expensive than Ethernet hardware and available from fewer vendors. Today Token Ring is found mostly in large corporate LANs.
In addition to Ethernet and Token Ring, there are other network types with smaller installed bases. Arcnet is an established type of standardized networking that has declined dramatically in popularity relative to Ethernet over the years.
While Ethernet and Token Ring promise to be the predominant types of networking for the rest of the decade, new, higher performance networking technologies are on the horizon. Fast Ethernet is a 100Mbps version of Ethernet based on CSMA/CD and twisted pair cable. 100VGAnyLAN (another 100Mbps network type) is a sort of hybrid of Ethernet and Token Ring and uses twisted pair cable as well but with a “demand protocol” which structures media access. Asynchronous Transfer Mode or ATM is a high performance network type (25 and 155Mbps data transfer) that can be used for both local and wide area networking. ATM is generally held to be the network of the future, showing a lot of promise but very little use at present.
A Wide Area Network (WAN) is a group of computers or Local Area Networks (LANs), not in the same location, which are connected together via a connection such as telephone wire. In other words, if you have a computer in New York City, which communicates directly and in real time with a computer in your office in Hong Kong, it is on a WAN.
As with a LAN, a WAN allows you to share files, printers and more, but now it is being done over much greater distances. With a WAN, employees (as well as suppliers and clients) can communicate more efficiently because of real time file sharing. Compared to LAN networks, WAN networks are more costly. However, the improvement in productivity and the financial benefits of that improvement can far outweigh the costs.
In the process of researching and assisting my mentor, Mark Malone, networking is truly an area of career opportunities. In installation and development of the networking, I look forward to an opportunity to gather information and develop my own network technology. The information I have learned has been very beneficial and has been a factor in my decision making for my future education and my future.