A network is basically a group of computers and other devices that are linked together in some ways to enable the exchange of data or pave the way for electronic communications. The devices or computers on a network can be linked through telephone lines, radio waves, cables, satellites and even infrared light beams.
Every device on a network can be thought of as a node, and every node has a distinct address. An address in this concept is a numeric quantity that is easy for computers to work with but not for us to remember. An example would be 22.214.171.124. Some networks, however, do provide names that we can remember more easily. For example www.codeschool.com, which, hypothetically, corresponds to the above address.
An Internet address consists of four bytes that are separated by periods an example being 126.96.36.199. The R(1,2,3) first bytes represent the network address and the H(3,2,1), or the remaining bytes are utilized for the host device.
The criteria used for the allocation of the address ranges corresponding to networks include:
1. The Country
2. The Organization
3. The Department
4. The Host
The Domain Name System
Also referred to as DNS, the domain name system is a mnemonic textual address that is provided to enable manipulation of an internet address.
The domain name system servers are tasked with translating the textual web addresses into numeric Internet addresses.
In this digital age, data is moved from one place to another through packet switching. Messages are broken down into units known as packets and then transferred from one device to the other. At the destination, the data removed from the packets is reconstructed back to the original message. Bear in mind that each packet consists of a header and a data section and has a maximum size. The packet header contains the source and destination computer addresses and sequencing info required to reassemble the original message at the destination.
An internet protocol address(IP) identifies the host machine on the web, and so, an IP port detects a certain application running on a web host device. A port is usually determined by a number which is known as the port number. Unlike serial communications, a port number isn’t functionality limited, but some port numbers are dedicated fro certain functions or applications.
So, what are the different types of computer networking?
Types of computer networking are usually classified depending on the geographical region covered by a network. Generally, there are two types of networks, Local Area Network, and Wide area network. We shall mainly take a look at these two, but we will also touch on Metropolitan Area Network and Personal Area Network.
Local Area Network(LAN)
A LAN is basically a network that’s used for communication among devices usually within a building, an office or a home.
Local area networks enable the exchange of resources or information such as files or even hardware devices that may be required by several users. This network is limited in size, typically a few hundred meters and no more than a kilometer. It is relatively fast with speeds between 10Mbps and 10Gbps. It has a lower cost compared to other networks and requires minimal wiring, usually a single LAN cable connecting to each computer.
Examples of Local Area Network technology include Token Ring, Ethernet, and Fiber. Ethernet LANs are based on a broadcast communication and bus topology. Token rings, on the other hand, are based on a ring topology, and Fiber LANs utilize optical fibers and an enhanced token ring mechanism.
A Summary of the Pros and Cons of LAN
-Enable resource sharing among devices
-Can be expensive to install
-Cables may break
-Call for administrative time
-And file server may fail.
Wide Area Network(WAN)
A wide area network covers large areas such as cities, countries, and continents. This is the biggest of the many types of computer networking, and it is created by connecting two or more LANs together. These LANs can be miles apart. To cover the vast distance, WANs transmit data over high-speed phone lines or even wireless links like satellites. The multiple LANs are connected using devices like routers, bridges, and gateways that enable them to share information. This network is based on packet switching technology, and the most popular type is the Internet.
Metropolitan Area Network(MAN)
This is a huge type of computer network that usually spans a huge institution or a city. It is a network optimized for a larger area than a local area network, ranging from several blocks to whole cities. A metropolitan area network might be owned and run by a single company, but numerous individuals and businesses will utilize it. It is often used as a high-speed means of sharing regional resources. A MAN usually covers a region of between five to fifty kilometers in diameter. Examples of metropolitan area networks include a cable TV network and a telephone company that offers high-speed DSL to consumers.
Personal Area Network(PAN)
This is a type of network used for sharing information across computers and other devices including smartphones and tablets within proximity of just a few meters within a room. A personal area network can be used for communication among the computers themselves or for communicating with a bigger network like the Internet. The devices used for this network may not belong to the creator, but the reach of the network is usually a few meters. A PAN can also be wired or wireless.
The Pros and Cons of PANs:
-A personal area network is lucrative, handy and expedient
-Bluetooth PANs may be slower, but they are relatively safe compared to other networks.
-However, Bluetooth has distance limits
-A PAN may have a poor connection to other networks if on the same radio band.
Now that we have mentioned and explained the different types of computer networking, let us take a look at interconnection and Network Topology.
These define the rules that control the communication between two devices that are connected to a network. The roles include routing and addressing messages, flow and sequence controls, detecting and recovering errors and much more.
A protocol specification includes the syntax, which is responsible for the types and formats of the exchanged messages and the semantic, which defines the action to be taken by every entity when certain events happen. An example is the HTTP protocol for communications between servers and internet browsers.
Low capacity networks can be connected through a backbone network which is basically a high capacity one such as a WAN or a Fiber network. Also, WANs and LANs can be interconnected through T1/T3 digital lines. In regards to the protocols in place, networks interconnection is achieved using the following devices:
Router- A communication gadget that connects various types of networks through various protocols
Bridge- A computer that links two similar local area networks that are based on the same protocol.
Gateway- A network gadget that connects two varying systems using systematic and direct translation between protocol.
B-Router- Also known as a bridge router, it’s a single gadget that combines the functionality of both a bridge and a router.
The internet protocol offers two main functionalities:
1. Breaking down the original information flow into packets and reassembling them back to the initial message at the destination.
2. Routing the packets through networks, from the source device to the destination identified by its internet protocol address.
Keep in mind that the transmitted packets are not guaranteed to reach the destination as the IP protocol doesn’t request for connection before sending data. The IP protocol also doesn’t make any error detection.
-Disintegrate initial data into datagrams. Every datagram will consist of a header which includes the IP address as well as the port number of the destination.
-Sending the datagrams to the chosen gateways such as routers that are connected at the same time to the LAN and the ISP(internet service provider) network.
-Transferring the datagrams from gateway to gateway until they reach the intended destination.
Transmission Control Protocol(TCP)
Transmission control protocol utilizes internet protocol packets as a basic service that ascertains safe delivery. That means that secure data transmission, error detection and assurance that data is delivered in the correct order is ensured. Before sending the data, transmission control protocol requires the devices communicating establish a connection, unlike IP protocol.
TCP also offers support for sending and receiving data as one huge stream of byte data. IP is usually limited to 64Kb. It achieves this by breaking the data stream into separate internet protocol packets. As mentioned earlier, packets are numbered and rearranged on delivery.
Transmission control protocol also enhances the capability of Internet protocol by specifying port numbers. There are over 60K different TCP sockets through which every TCP and IP device can talk.
User Datagram Protocol(UDP)
UDP is ideally built over IP, but it has the same limit for packet size as IP. However, UDP allows port number specification and also provides over 60K different ports. That means that every device has two sets of these many ports, one for UDP and the other for TCP. However, UD protocol is connectionless and doesn’t facilitate error detection. It also only provides data transmission from one end to the other without further verification. The biggest advantage of UDP over other protocols is that it is very fast since it does not provide further verification. That makes it ideal for small size data in a repetitive manner.
This is the specific, whether the virtual, logical or real organization of the elements of a network. Two networks will have the same topology if the configuration of the connections between them is the same. However, the networks may differ in distances between nodes, signal types, physical interconnections and the transmission rates.
There are generally two types of topology, Vertical, and Horizontal, both of which have sub-types as well.
Horizontal Topology consists of:
-Bus topology where all the stations are interconnecting using a single Bus
-Ring topology where every node has two branches connected to it
-Star Topology where peripheral nodes connect to a central node or switch which redirects all transmissions to all peripheral nodes on the network including the originating one.
Vertical Topology consists of:
-Hierarchical or Tree topology where there are a central node and a number of level organized node sets. The information flow between any nodes goes up and down using the upper-level nodes.
-Mesh Topology where there are at least two nodes or switches with two or more paths between them.