Network and Telecommunications Concepts - Assignment Example

Computer Assignment .. SECTION We are well aware that the computer technology is younger. Yet a great part in this field is being covered by networking. And we should be well aware of networking. The question arises what actually is networking? A node is a device which is capable of sending or receiving data from other nodes and when these nodes are connected with each other through different links then if forms a network. These links are actually called communication channels. The way to connect a network system is a called topology. It refers to the layout of the connected devices. Topology can also be defined as a physical configuration of cables and connections which comprises a network. Topology can be referred as the shape of the system. Following major topologies are in use today. Bus Ring Star Mesh We shall now discuss them one by one. 1. Bus Topology Bus topology is the simplest to understand. All the devices are connected to a common cable on the network in the bus topology. This cable is not allowed to form a closed loop and is terminated at the ends. All devices are connected to a common backbone. T-Connectors are used to connect to this backbone. A device that wants to communicate to another device sends the message through the wire that all other devices can see but only the recipient who is intended to receive the message can receive the actual message. Bus topology is comparatively easier to install. It also does not require many cables. 10 Base-2 and 10 Base-5 are popular cables. Only a limited number of devices make bus networks work best. Performance problems may arise if only a few dozen computers are added to the network. Further its drawback is that if one cable fails, the entire network becomes unusable. Advantages Disadvantages Implementation is cheap and easy Adding/Removing computers causes network disruption Less cable is required Breakage of cable causes prevention of all systems from accessing the network. No specialized equipment is required Troubleshooting is difficult Figure 1 Bus Topology Image Source: eden.creighton.edu/mis253n_fall2007/supplements/Network%20Topologies.pdf 2. Ring Topology Ring topology is somewhat similar to bus topology. All the devices on the network are connected to a common cable in a ring topology which goes from machine to machine. After the last machine on the network the cable returns back to the first one. Data travels in a circular fashion from one computer to the next one. For communication reasons every device has two neighbors in ring topology. Message is traveled through the ring in the same direction. FDDI, SONET or Token Ring Technology is used to implement ring network. Office buildings or school campuses uses ring topology. Advantages Disadvantages Troubleshooting becomes easier as cable faults can easily be located Network disruption is caused by expansion to the network It is easy to install ring networks The entire network can be disrupted by a single break in the cable Figure 2 Ring Topology Image Source: eden.creighton.edu/mis253n_fall2007/supplements/Network%20Topologies.pdf 3. Star Topology It is completely different from Ring and Bus Topologies. Hub is the central connection point in star topology. Each device is separately connected to the hub or communicator in star topology. Each device can use only one port on the hub and thus requires a single cable. It is the most widely implemented network. Advantages Disadvantages Easily expandable without disruption More cable is required A single user is affected by cable failure A single point of failure is allowed by a central connecting device Easy to troubleshoot Its implementation is difficult Figure 3 Star Topology Image Source: eden.creighton.edu/mis253n_fall2007/supplements/Network%20Topologies.pdf 4. Mesh Topology Concept of routing is involved. Every device is physically connected to every other device in mesh topology. It provides a great performance and reliability but complexity and difficulty also increases. There is high level of redundancy in mesh networks. Advantages Disadvantages Redundant path is provided between devices More cable is required Without disruption to current users, the network can be expanded Implementation is complicated Figure 4 Mesh Topology Image Source: eden.creighton.edu/mis253n_fall2007/supplements/Network%20Topologies.pdf Ethernet It is a technology which is frame based for local area networks. A type of plug connection which connects PC to routers and switches etc is Ethernet and is a networking port. IEEE 802.3 is standardized for Ethernet. For connection of end systems to the network, combinations of versions of Ethernet which are twisted pair along with versions of fiber optic are a very widespread local area network (LAN) technology. It is largely replacing and competing LAN standards e.g. Token Ring, FDDI and ARCNET and is being used from 1990s. FDDI The standard for data transmission in a local area network is provided by Fiber Distributed Data Interface (FDDI). It can range 200 kilometers. FDDI is in fact a token ring network but IEEE 802.5 is not used by it. IEEE 802.4 is its protocol. Thousands of users are supported by FDDI in addition to its large coverage of geographical areas. It uses optical fiber along with dual attached counter rotating token ring technology. It is used where connecting multiple buildings is a part of our requirement. Token Ring The idea for token ring local area network was given in 1960s by IBM. It is standardized as IEEE 802.5 and IBM promoted it in early 1980s. It gained a great success in the beginning but its decline started Ethernet and EIA/TIA 568 cables were introduced in early 1990s. In it one system is connected to another by ring form. Its cars are expensive and it uses a special cable. Due to great efforts by IBM it gave better performance and became more reliable over Ethernet but was not very successful. Now token ring is not being promoted by IBM. Wireless The wireless term is normally used to refer any electrical operation where hard wire connection is not being used. The transfer of information over some distance without the use of electrical wires is wireless communication. This distance can be short or very long. Wireless communication comes in the branch of telecommunications and it uses radio waves to transmit data over distances. The wireless local area network works on a wireless technology and is commonly known as Wi-Fi (Wireless Fidelity). It is based on 802.11 standards. The problem of hacking can arise if not configured properly. Internet, network connectivity, gaming and VoIP phone access are common applications of Wi-Fi. It is good for laptops and other small movable devices. SECTION 2 A set of communication protocols used for the internet and other networks is the Internet Protocol Suite (TCP/IP). It is named from two main protocols i.e. Transmission Control Protocol (TCP) and Internet Protocol (IP). These are the first two networking protocols. IP Data from node to node is transferred by IP. Packets are sent by IP on a four byte destination address called the IP number. The ranges of numbers are assigned to different organizations by different authorities. Then groups of their numbers are assigned to departments by these organizations. Data is moved by IP from department to organization and then to region and then around the world. TCP Correct delivery of data from to server is verified by TCP. Intermediate network can be a reason for data loss. TCP can detect lost data and errors and transmit data again and again until it is not completely received. Sockets Socket is the name of sub routine from where TCP/IP can be accessed on most systems. OSI Open Source Interconnection (OSI) is a networking frame that implements protocols in seven layers. Control passes from one layer to the next, starts at the application layer then proceeds to bottom layer and back up to hierarchy. Most functionality in OSI models exists in communication systems. Two or three OSI layers although may be incorporated into one. TCP/IP And OSI Both TCP/IP and OSI share similar architecture. This can be illustrated by the fact that both models and built with layers. They also contain common application layer. Their network and transport layers are comparable. Like OSI TCP/IP also assumes then packets to be switched. It basically means that in order to reach same destination, different paths may be taken by individual packets. The upper layer of both models is connected to lower layer to the actual physical network. Lower layer is called the physical layer in OSI model where in TCP/IP model, the lower layer is called host to network layer. Nowadays a combination of layer 2 called medium access control along with layer 1 is used by TCP/IP. Thus wireless link connectivity is provided by it. All evaluated wireless equipment features virtually operate at data link, physical and network layers of TCP/IP and OSI reference models. Wireless features are taken place at physical layer. Sharing of wireless medium is taken place at the data link layer and the network layer provides routing. References Andrew S. Tanenbaum. (2003). Computer Networks. London. Prentice Hall. Brenton, C. & Hunt, C. 2003. Network Security. 2nd Ed. New Delhi: BPB Publications. Hossein, B. 2005. The Handbook of Information Security. John Wiley & Sons, Inc. John L. Hennessy, David A. P, Andrea C. A. (2007). Computer Architecture: A Quantitative Approach Morgan Kaufmann Larry L. Peterson. (1999). Computer Networks: A Systems Approach. Morgan Kaufmann Publishers. Read More