Networks are a vital to the business use of computers, especially for the applications and data that networks can deliver. A group of interconnected computers are commonly known as a computer network. There are different types of networks and are classified by its characteristics. Networks have a wide variety of classifications but I'm going to into detail for only a few. The most common classifications are Local Area Network, Wide Area Network, Metropolitan Area Network, and Virtual Personal Network. In addition to the classification of networks, they also go by the types of logical and physical topology. The most common are known as Bus Topology, Ring Topology, and the Star Topology. Last but not least, all types of network follow the 7 layers of the OIS Model.
Local Area Network or LAN is the most commonly used of the classification. It could be found at homes if they have more than one computers, offices, stores, schools and even airports. It covers a small physical area, its fast transferring information. It allows computers to interaction with each other, such as sharing data, sharing printers, and access to the internet. LAN is the basic block for building a large network called internetwork and WAN. Wide Area Network or WAN has all of the option of a LAN with the exception that is not as fast because of its broad area that covers. The WAN distance is measured in miles and links two or more separated LAN. It used routers and public communication links. The internet is the most commonly known example used to describe a Wide Area Network. WAN technology uses the services of third- party communications provider, such as telephone companies, to carry network traffic from one location to another. A Metropolitan Area Network or MAP is a type of network that uses WAN technology to interconnect LAN's within a specific location, such as a towns or citywide access. Metropolitan Area Networks don't have the ability to extend themselves from their specific location boundaries. Recently MANs have received a boost in popularity because of the growing trend in some major cities to implement a citywide wireless network. On the other hand, Virtual Personal Network or VPN is more like links between nodes that are carried by an open connection. It's often used for secured communication and to transfer information through the public internet.
Physical Topology and Logical Topology have the basic concept. The main difference is that the logical topology is how the data travels between computers on a network and the physical topology is the arrangement of the cabling in the network. A Physical Bus Topology or also known as a linear topology is the simplest and at one time the most commonly used. Although it is the simplest, it's also the weakest. All components of the buss topology are connected via a single cable segment called the backbone, and interconnect all the computers in a straight line. This is the reason why is the weakest, a single break on the cable could stop the entire connection of the network. Physical topology is no longer a practical choice because of the advancement in technology has made it an obsolete method for connecting computers. The Logical Buss Topology describes the path that data travels from computer to computer until it finds where the data has to go. Physical Ring Topology is when each computer connects directly to the next computer in line, ending at the starting computer creating a circle. Every computer in the ring is responsible for retransmitting the information. The single ring topology could fail if only one of the computers in the ring fails, but a dual ring topology could continue working if one of the computers fail. In a logical ring topology, the data travels from one device to another in the network until it reaches its destination. The way it sends data around the ring is by a small packed called a token. The token is send around a ring until a computer has data to be sent to another computer or destination. Only one computer is allowed to send information at a time and the rest of the computers have to wait. The most commonly use topology is the Star Topology. In a physical star topology every computer on the network is connected to a central device, mainly a switch that is connected to a router. It is easier to solve a problem because of its centralization, it also consumes more cabling, and if the central device fails, the whole networks goes down, but if one computer fails, nothing happens to the network. In the case of a Logical Star Topology, well there is none. Star topology could use either logical bus or logical ring topology and often called a star bus topology or a star ring topology, using the physical aspect of cabling as a star topology and using logical bus or ring topology to how it sends data from one computer to its destination.
Every network has to follow the 7 layers of the OIS Model or Open System Interconnection Model. The OIS is the key part of networking; it defines a networking framework for implementing protocols in seven layers. Starting from top to bottom, the application layer or layer 7 provides a set of interfaces for applications to access networked services to the end user. Presentation layer or layer 6 handles data formatting for network communication. Session layer or layer 5 permits two parties to hold ongoing communication across a network. Transport layer or layer 4 manages the transfer of data from one application to another. Network layer or layer 3 handles addressing messages for delivery and translates logical network addresses into is physical counterpart known as Mac address. Data link layer or Layer 2 sends data from the network layer to the physical layer. And the physical layer or layer 1 converts bits into signals for outgoing messages and signals into bits for incoming messages.
Networks can be categorized in several different ways. The most common is by their geographic area it spans. LAN used as basic as for a single home, to buildings and even airports. WAN are uses for connecting more than one LANs or MAPs to create an internetwork. MAN ability that uses WAN technology to interconnect LAN's within a specific location, such as a towns or citywide access, and VPNs secure communication and transfer information through the public internet. Computer networks also differ in their design. The network topology represents its layout or structure from the point of view of data flow. The Open Systems Interconnection Model is an abstract description for layered communications and computer network protocol design. Computer networks are a vital part of communication in our lives now in days. This is only a small portion of what a computer network is composed.