Internet Technologies At Work
Chapter 10: Networking Fundamentals
After completing Chapter 10, you will know how to:
- Define the term networking and list the three critical components that must be present in a network.
- Define the five networking topologies used in describing the physical layout or shape of a network.
- Define the seven layers in the OSI Reference Model, and identify the networking protocol suites that follow it.
- Explain the difference between a local area network (LAN), metropolitan area network (MAN), and a wide area network (WAN).
- Define the physical network components that LANs, MANs, and WANs comprise.
Definition
A network is the connection of two or more digital devices for the purpose of communicating, transferring, or obtaining data. In order to have a network, you must have three things that are characteristic of all networks. First, there must be a physical connection through which the data will flow. Second, there must be a set of communication rules called protocols that the networked devices use to communicate. Third, there must be one or more network services that will receive these communications and respond by providing the informational resources that are the reason why you want to create a network in the first place.
Push/Pull Metaphor
If you think about how you get information from a network, there are basically two ways to receive it. Either you ask for it, and the information appears on demand each time you request it; or you subscribe to an information service, which provides you with the information automatically when the data becomes available. The computer industry uses the push-pull metaphor to distinguish between these two ways of receiving information.
When you browse the Web and click hyperlinks that bring requested resources onscreen, for example, you are pulling the information toward you. Thus, hyperlinks are an example of pull technology.
Push technology can broadcast important messages to network users. In a weather emergency, for example, a Windows network administrator can use the "net send" feature to push a warning message onto each logged-on worker's screen. Users who want to monitor the weather continuously can download the WeatherBug from www.weatherbug.com. The current temperature displays on the Windows status bar, and impending weather emergencies push warnings onto your screen.
OSI/RM Layers
If you are studying for the CIW Foundations exam, you need to memorize the names and the order of the seven OSI/RM layers. Networking professionals use a seven-word slogan to help people remember the order of these layers. The slogan is "All people seem to need data processing."
Application Layer | Presentation Layer | | Session Layer | | | Transport Layer | | | | Network Layer | | | | | Data Layer | | | | | | Physical Layer | | | | | | | All people seem to need data processing.
IEEE 802.x Standards
The Institute of Electrical and Electronic Engineers (IEEE, pronounced I triple-E) is in charge of defining the networking standards that connect devices together to form different kinds of local and metropolitan area networks. The IEEE’s LAN/MAN Standards Committee (LMSC) performs this work under IEEE Project 802. This committee is organized according to working groups that are in charge of defining the networking standards. These groups are numbered from 802.0 through 802.20, as are their corresponding standards.
The 802.2 standard is the Logical Link Control (LLC) sublayer of the OSI/RM data link layer. The other sublayer is the Media Access Control (MAC). Most of the other 802 standards, including 802.3 and 802.5, mainly define the MAC sublayer for different kinds of networks. IEEE standard 802.3 defines CSMA/CD (Ethernet), and 802.5 defines Token Ring.
When a new standard gets created, it is available only to IEEE members for a period of six months. After this waiting period, the LMSC publishes the standards at www.ieee802.org, where anyone can download and study them.
End of Chapter Labs
Lab Project 10.1: Network Needs Analysis
Imagine that you work for a mid-sized company or school district that is looking to revamp its networking strategy. There are several buildings to interconnect, each of which contains a couple dozen workstations that need to function as nodes on the network. Your employer has assigned you the task of analyzing their needs and recommending alternative networking strategies. As part of this analysis, you employer wants to know the relative advantages and disadvantages of each alternative in order to make an informed decision regarding the networking strategy your organization should adopt. Use your word processor to write an essay in which you assess the needs and discuss the relative pluses and minuses of possible networking alternatives. In developing this needs assessment, consider the following issues:
- Bandwidth requirements. What are the bandwidth requirements of the workers who use the network? Do some of the buildings have higher bandwidth requirements than others?
- Comparative analysis. Compare alternative methods for providing this bandwidth. Search Google or Yahoo for networking companies, and peruse the LAN and MAN solutions provided by the major manufacturers, such as Cisco, 3Com, and Nortel. What appear to be the best alternatives for providing the required bandwidth?
- Architecture and topology. Discuss the relative advantages and disadvantages of the different networking topologies that appear to be relevant in the context of this analysis.
- Network operating system. What network operating system(s) will the workstations need to run in order to access the network? Are the recommended operating systems already running on these workstations, or will new software need to be obtained?
- Scope of work. Consider the amount of work that will be required to implement the various alternatives you are putting forward, and include an estimate of the amount of time it will take to accomplish them.
If your instructor asked you to hand in the needs analysis, make sure you put your name at the top of the essay, then copy it onto a disk or follow the other instructions you may have been given for submitting this assignment.
Lab Project 10.2: Network Design
Your mid-sized company or school district has asked you to design a hybrid network in which you will use an appropriate mix of networking topologies to provide efficient and reliable connections among the local area networks operating in five different buildings that are within a 10-mile radius. At the moment, these LANs are using a bus topology that is prone to slow down under heavy traffic, and which is time-consuming to repair when a node goes down and renders the LAN unusable. Connections between the LANs are slow due to the use of legacy X.25 lines leased from the local telephone company. Use your word processor to write an essay in which you present an improved network design for solving these problems. In developing this design, consider the following issues:
- LAN topology. You clearly need to replace the bus networks with a better LAN topology. Which topology do you recommend for the LANs within each building?
- MAN topology. The physical distance between buildings is within the geographical radius of metropolitan area network technology. What MAN topology is most appropriate for your network design?
- WAN connection. What WAN protocol or method will you use to connect the MAN to the Internet?
- Integration. How can your design better integrate the organization’s programs and services? If there are databases that serve information through different business processes that interact with end users, for example, could a multi-tier approach make the development, production, and maintenance of these processes more efficient?
- Wiring plan. What kind of wiring does your plan require? Specify the wiring categories, and state whether any of the existing wiring can continue to be used.
- Wireless facilities. If users will be accessing the network via wireless devices, specify the WAPs needed to connect them.
- Draw the network diagram. Depending on your artistic ability, you may find it helpful to use a networking clip art library or design tool. To find these tools, search Google or Yahoo for network design, network symbols, or network clip art. See also the public domain Cisco icon library at www.cisco.com/web/about/ac50/ac47/2.html, where you will find full color and black-and-white icons as well as stencils for drawing network diagrams with Microsoft Visio.
If your instructor asked you to hand in the network design, make sure you put your name at the top of the essay, then copy it onto a disk or follow the other instructions you may have been given for submitting this assignment.
