Circuit Switching
Circuit switching dominates the public switched telephone network or PSTN. Network resources set up calls over the most efficient route. That might mean a call from New York to San Francisco goes through switching centers in San Diego, Chicago, and Saint Louis. But no matter how convoluted the route, that path or circuit stays the same throughout the call. Got it? One call, one circuit. It's like having a dedicated railroad track with only one train, your call, permitted on the track at a time.
Packet Switching
Packet switching dominates data networks like the internet. A data call or communication from San Francisco to New York is handled much differently than with circuit switching. With circuit, all packets go directly to the receiver in an orderly fashion, one after another on a single track. Like the train we mentioned before, hauling one boxcar after another. With packet switching routers determine a path for each packet or boxcar on the fly, dynamically, ordering them about to use any railroad track available to get to the destination. Other packets from other calls race upon these circuits as well, making the most use of each track or path, quite unlike the circuit switched calls that occupy a single path to the exclusion of all others.
LAN
A local area network (LAN) is a group of interconnected computers that share the same geographic location, such as an office. This is opposed to a wide area network (WAN), which connects computers over greater distances, and would be used to link branch offices.
Each computer connected to a LAN is able to access the other connected computers' hard drives, as if they were installed internally. Also, you can connect your LAN to a file server, which is specifically designed to house shared files and resources for all the networked computers to access.
WAN
A WAN is a data communications network that covers a relatively broad geographic area and often uses transmission facilities provided by common carriers, such as telephone companies. WAN technologies function at the lower three layers of the OSI reference model: the physical layer, the data link layer, and the network layer.
A point-to-point link provides a single, pre-established WAN communications path from the customer premises through a carrier network, such as a telephone company, to a remote network. A point-to-point link is also known as a leased line because its established path is permanent and fixed for each remote network reached through the carrier facilities.
... access to what and in which sequence. The router connects the LAN to other networks, which could be the Internet or another corporate network so that the LAN can exchange information with networks external to it. The most common LAN operating systems are Windows, Linux, and Novell. Each of these network operating systems supports TCP/IP as their default networking protocol. Ethernet is the dominant LAN standard at the physical network level, specifying the physical medium to carry signals between computers, access control rules, and a standardized set of bits used to carry data over the system. Originally, Ethernet supported a data transfer rate of 10 megabits per second (Mbps). Newer versions, such as Fast Ethernet and Gigabit Ethernet, support data transfer rates of 100 Mbps and 1 gigabits per second (Gbps), respectively, and are used in network backbones.
Meanwhile, the advent of early PC’s and the recognition of the value in networking devices together gave rise to Local Area Networks. These LAN’s were developed from a business customer perspective, which placed more emphasis on costs and ease of use over reliability. There were a number of different competing LAN technologies, two of the most common being Token Ring (IBM) and Ethernet (everyone else). The triumph of Ethernet in the marketplace, to the extent where it is included in every PC, game console and some refrigerators, provides a consistent and relatively inexpensive way to build internal networks with relative ease.
A network can be based on either a peer-to-peer level or server-based, also referred to as domain-based. To distinguish the difference, a peer-to-peer network, also known as a workgroup, is a network in which a group of computers are connected together to share resources, such as files, applications, or peripherals. The computers in a peer-to-peer network are peers to one another, meaning no single computer has control over one another. There is also no central location for users to access resources, which means that each individual computer must share their files in order for other computers to have access (Muller, 2003, p.411). “In a peer-to-peer environment, access rights are governed by setting sharing permissions on individual machines.” (Cope, 2002) On the other hand, in a domain-based network, the computers connected together are either servers or clients. All of the other computers connected to the network are called client computers. The server is a dedicated machine that acts as a central location for users to share and access resources. The server controls the level of authority each user has to the shared resources. When logging on to the network, users on client machines are authenticated by the server, based on a user name and password (Lowe, 2004, p.13).
In an organization, systems are deployed and configured in the LAN – Local area network. The LAN is the private network of the organization. The public network refers to the internet. Devices on the private network are not directly connected to the public network. The organization would use devices like routers, firewalls to provide public network access to the private network users.
Perhaps the most redundant, fault-tolerant of all network topologies is the mesh LAN. Each node is connected to every other node for a true point-to-point connection between every device on the network.
Local Area Networks also called LANs have been a major player in industrialization of computers. In the past 20 or so years the worlds industry has be invaded with new computer technology. It has made such an impact on the way we do business that it has become essential with an ever-growing need for improvement. LANs give an employer the ability to share information between computers with a simple relatively inexpensive system of network cards and software. It also lets the user or users share hardware such as Printers and scanners. The speed of access between the computers is lighting fast because the data has a short distance to cover. In most cases a LAN only occupies one or a group of buildings located next to each other. For larger area need there are several other types of networks such as the Internet.
For enterprises, the current cost of a traditional circuit-switched PBX and a VoIP system are roughly similar, at about $500 a seat, due to the larger cost of IP phones. However, enterprises with branch offices can re-use their VPN or leased lines for intra-company voice communications and can avoid having to lease small numbers of phone circuits at each branch office. It is well known that a single large trunk for a large user population is more efficient than dividing the user population among smaller trunks, due to the higher statistical multiplexing gain. Enterprises can realize operational savings since moves, additions and changes for IP phones are much simpler, only requiring that the phone be plugged in at its new location.
This report will describe the two forms of data communications in terms of the physical interfaces and modes of operation. It will describe the features of data communications equipment in relation to synchronous and asynchronous communication including modems, network terminating units and sending and receiving equipment.
Since its inception, the telephone has become one of the most important inventions of all time. Although some were skeptical about its replacement over telegrams, in the end the advent of this fine communication equipment has won the hearts of many. As a matter of fact, the telephone system had come to numerous facelifts that it literally connected the world before the internet was born. Because of its importance, homes and businesses can not live without it. In the U.S. alone, most if not all have a phone in the house.
Now we will discuss some of the key components of any telephone network. These components are loops, lines and trunks. “Loop transmission facilities connect switching systems to customer premises equipment throughout the serving area. A loop is a transmission path between a customer's premises and a local exchange carrier (LEC) central office” (Loop Transmission). A line is a communication connection between your telephone and the local phone company’s switch, such as a PBX or a CO switch. No that we know that a line connects a telephone to the switch, the next stage is the trunk. A trunk is a shared communication channel that connects multiple telephone switches together and has the ability to transfer a telephone call from one location to the next.
A network is a collection of entities that exchange information or good. Few examples of networks are nervous system, traffic light system, railway system etc. Computer Network is normally known as a system of interconnected computers & communication devices that can communicate with one another and share resources. At the most elementary level computer consist of two computers connected with each other by a cable to allow them to share data .A device connected to a network is called a node. A node may be a device such as a computer, a printer, workstation etc.
My mobile phone network coverage allows me to make a call wherever I want, and the call is never cut off by the network. Independent surveys show that it has the best signal quality with excellent call clarity. The network covers 99 percent of the population, and it has installed more transmitters than any other digital network company. They guarantee that they work the best; in fact, they will even add a free minute of talk time if the call is ever lost. International and off-peak calls are the cheapest in the area. The company has been voted number 1 in customer satisfaction for 5 years in a row.
Making a telephone call no longer should conjure up visions of operators connecting cables by hand or even of electrical signals causing relays to click into place and effect connections during dialing. The telephone system now is just a multilevel computer network with software switches in the network nodes to route calls get through much more quickly and reliably than they did in the past. A disadvantage is the potential for dramatic and widespread failures; for as has happened.
TCP/IP is a network model which enables the communication across the Internet. The most fundamental protocol on which the Internet is built. This is made up of the 2 common networking protocols, TCP, for Transmission Control Protocol, and IP, for Internet Protocol. TCP maintains and handles packet flow linking the systems and IP protocol has the ability to handle the routing of packets. However The TCP/IP stack consists of 5 layers first being application layer, the transport layer, then the network layer, the link layer and finally the physical layer. The assignment focuses on the three middle layers and is divided into five parts. Firstly explaining how the TCP and UDP the most vital protocols needed to deliver and communicate.
People in the present society have turned from the use of the old means of communication to the more advanced and technological ways of communicating. Technology has made it easier for people to communicate in a faster, efficient, and cost saving means through the introduction of the communication channels. The world has turned out to be the centre for technology with different technologies emerging daily as the people continue to develop from time to time to cope with the growing technology. The benefits of adopting the communication technology are explained in this article which shows why people do not function without technology.