Chapter 7
7-5: Packet switching, client/server computing, and the TCP/IP protocol are the three foundations for the Internet. Explain the function and importance of each.
COLLAPSE Packet switching, client/server computing, and the TCP/IP protocol are the three foundations for the Internet. Explain the function and importance of each. Packet switching: The techniques prior to packet-switching were expensive and wasted available communication capacity due to the leasing of dedicated circuits to communicate. Client/server computing: This technology has made it possible for personal computers to be connected to the internet. What this technology has done is ease the access of computing processing to the departments, workgroups, etc that previously had no access to the centralized mainframe computers. TCP/IP: TCP/IP replaced the previous protocols that needed computing and communications network to all be sourced from a single vendor in order to transmit data. What the new protocols have done is make it possible to connect two computers regardless of physical distance and transmit any data.
7-6: Discuss the three network topologies presented, giving an advantage and disadvantage of each.
Qn; 6 Discuss the three network topologies presented, giving an advantage and disadvantage of each. Star Topology All computers and devices are connected to a centrally located hub or switch. The hub or switch collects and distributes the flow of data within the network. It's better to use a switch than a hub because a switch transmits the data to the intended recipient rather than to all hosts on a network. When a node wants to send a message to the other nodes, it first sends the message to the hub, which in turn forwards the message to the intended node. Each node in the network is connected with a point-to-point link to the centralized hub. The task of hub is to detect the faulty node present in the network. On the other hand, it also manages the overall data transmission in the network. It's advantages are: It allows easy error detection and correction. The failure of one computer does not affect the other computers in the network. It's easy to install. It's disadvantages are: The hub failure leads to the overall network crash. The star topology requires more amount of cable for connecting the nodes. It is expensive due to the cost of the hub. 2) Linear Bus Topology All computers and devices are connected in series to a single linear cable called a trunk or sometimes called a backbone or bus with some medium such as twisted pair, coaxial cable etc. Both ends of the trunk must be terminated to stop the signal from bouncing back up the cable. Because the bus topology does not have a central point it is difficult to troubleshoot problems. When a node wants to communicate with the other nodes in the network, it simply sends a message to the common bus. All the nodes in the network then receive the message but the node for which it was actually sent only processes it. The other nodes discard the message. It's advantages are: It usually requires less cabling. It is relatively simple to configure and install. The failure of one computer does not affect the other computers in the network. It's disadvantages are: The failure of the backbone cable results in the breakdown of entire network. Addition of computers in the linear bus topology results in the performance degradation of the network. It's difficult to reconstruct in case of faults. 3) Ring Topology All computers and devices are connected to cable that forms a closed loop. Each computer on this type of topology acts like a repeater and boosts the signal before sending it to the next computer. It transmits data by passing a "token" around the network. the nodes are connected in the form of a ring with the help of twisted pair cable. Each node is connected directly to the other two nodes in the network. The node, which wants to send a message, first passes the message to its consecutive node in the network. Data is transmitted in the clockwise direction from one node to another. It's advantages are: Each node has an equal access to other nodes in the network. Addition of new nodes does not degrade the performance of the network. It's easy to configure and install. It's disadvantages are: It is relatively expensive to construct the ring topology. The failure of one node in the ring topology affects the other nodes in the ring.
7-2: -Give a brief history of the major milestones in the development of the internet.
Give a brief history of the major milestones in the development of the internet. 1962: The first recorded description of the social interactions that could be enabled through networking was a series of memos written by J.C.R. Licklider of MIT in August 1962 discussing his "Galactic Network" concept. He envisioned a globally interconnected set of computers through which everyone could quickly access data and programs from any site. In spirit, the concept was very much like the Internet of today. 1966-1967: Lawrence G Roberts went to DARPA to develop the computer network concept and quickly put together his plan for the APRANET publishing it in 1967. 1972: In October, Robert Kahn organized a large, very successful demonstration of the ARPANET at the International Computer Communication Conference (ICCC). 1974: Robert Kahn of DARPA and ARPANET and Vinton Cerf of Stanford University work to unify the network ideas of the ICCC. In their work, it contains the first attested use of the term internet, as a shorthand for internetworking 1975: ARPA gives the network over to the Department of Defense 1984-1988: CERN began installation and operation of TCP/IP to interconnect its major internal computer systems, workstations, PCs and an accelerator control system. 1989: Tim Berners-Lee is credited with inventing the World Wide Web 1990: Tim Berners-Lee developed both the first web server, and the first web browser, called WorldWideWeb 1993: Marc Andreessen creates Mosaic which is credited as being particularly easy to use and install, and often credited with sparking the internet boom of the 1990 1999: Web 2.0 surfaces, leading to cumulative changes in the way Web pages are made and used in which sites focus substantially upon allowing users to interact and collaborate with each other in a social media dialogue as creators of user-generated content in a virtual community in contrast to Web sites where people are limited to the passive viewing of content The Mobile Revolution also greatly changed the Internet, as it and Web 2.0 led to a more personalized Internet experience
7-1: Present the TCP/IP Architecture Layers and discuss the functions of each layer.
TCP/IP-Transmission Control Protocol/ internet Protocol-Developed by the US Department of Defense. - Because it provides the basic framework for Internet communications, TCP/IP is sometimes also referred to as suit of Internet Protocols Suite. With the common one being TCP and IP. TCP establishes the connection between two computers, sequences the transfer of packets, and acknowledges the packets sent. IP refers to the Internet Protocols (IP) and responsible for the delivery of packets and includes the disassembling and reassembling of packets during transmission. TCP/IP has four layers: Application, Transport, Internet, & Network Interface layers. Application Layer: enables client application programs to access other layers and defines the protocols that applications use to exchange data. One of these application protocols is the hyper text transfer protocol (http) which is used to transfer webpage files. Transport layer: the transport layer is responsible for providing the application layer with the communication and package services. This layer includes TCP and other protocols. Internet layer: the internet layer is responsible for addressing routing, and packaging data packets called IP datagrams. The internet protocol is one of the protocols used in this layer. Network interface layer: At the bottom of the reference model, the network interface layer is responsible for placing packets on and receiving them from the network medium. which could be any networking technology. Data sent from one computer to the other passes downward through all four layers, starting with the sending computers application layer and passing through the network interface layer.
