Chapter 8: Designing and Installing a Network
Because peer-to-peer Ethernet can be implemented in the form of either a physical bus or a physical star, you will need to look at these two different topologies in planning for this network. On separate paper, draw:
Though your drawings might not be as complex as these, you should have illustrated the following, at a minimum:
Physical bus—All computers should be connected individually to a point on the bus. Each peripheral should be connected to the appropriate computer.
Physical star—Each computer should be connected to a central hub with an individual cable. Each peripheral should be connected to the appropriate computer, and there should be no terminators.
Figure 1 Sample network as a physical bus
Figure 2 Sample network as a physical star
While there is no one-size-fits-all correct form for this design, there are a few things you must take into consideration when you design the network. Check to see if you considered these factors.
For the logical bus with physical bus, did you:
For the logical bus with physical star, did you:
Make a materials list for each of the topologies. Using the facility drawing provided earlier in Figure 8.1, identify the location of each workstation and estimate all the materials you will need to complete the job. Use the following table to help determine which materials are required.
|Logical bus; physical bus||Logical bus; physical star|
|Type of Cable|
|Length of Cable|
|Connectors (type and count)|
Once again, there is no one-size-fits-all approach to selecting materials for networking. What is important is the process: thinking through the design and building the network on paper before you begin to spend money and time on the installation. You should take into account differences, such as cost, between the two types of network topology. For example, a small thinnet physical bus design is less material-intensive than a physical star.
In Exercise 8.1, we designed a peer-to-peer network and looked at two different topologies. While these designs meet the immediate needs of our client, the custom bicycle manufacturer, they are likely to fall short if the manufacturer decides to expand the business in the future. In this exercise, you will be modifying the design you carried out in Exercise 1 to include a network server.
In planning your new design, consider the following issues:
From the standpoint of networking requirements, the server can be placed in any location provided it is connected correctly to the media. Thus, while it is necessary to locate the server where it can be accessed physically, it need not be centrally located. The logical choice would be to place it in a room by itself. However, in our client's office, no such room exists. The Accounting Department or the Product Design Group offer two possible locations. The server will be more physically secure in the Accounting Department office, where there is likely to be less traffic and where the door will probably be locked when the office is unattended. The office of the Product Design Group is another location in which the server could be somewhat isolated. The advantage of this site is that staff members in this department, who are likely to be computer-literate, will be on hand and can watch over the server's welfare.
When a network server is added to an existing peer-to-peer network, at least one computer must be added to the existing number. With a small network, such as that we are creating for our bicycle company, a single server can supply all the expected resources, including files, printers, and applications. Making the physical connection is the same as for a workstation: if the server computer is in the same location as the hub, simply connect it with a patch cable. Otherwise connect the server with an available cable in one of the vacant work areas.
Compatibility is another issue to consider. Each workstation needs to communicate with the server. Depending on which network operating system is installed, some of the computers on the network might need to be upgraded to meet the minimum requirements of the server.
What steps do you need to take in order to successfully connect the new computer to the existing company network?
First, set up the computer and verify that it is in good working order. If the operating system allows it, check for available interrupts in case this information is needed when you configure the network interface card. Make a note of the computer's installed RAM and disk capacity; these might be inadequate for network use or for resource-intensive applications.
Once you have determined that the computer runs correctly and have taken notes on its configuration, close any applications and shut down the operating system. Disconnect all cables and open the CPU. Examine the main board for available bus slots, noting the type of slot or slots available. If a PCI slot is available, it should be your preferred choice; if not, an Industry Standard Architecture (ISA) slot might be available. (ISA is discussed in Chapter 2, "Basic Network Media.")
Obtain a network interface card of the correct bus type—PCI or ISA—and cable connector type—BNC or UTP—for the bicycle company's existing network. Remember that if the existing network has 100Mhz UTP cabling, the card needs to be capable of operating at that speed.
Compatible drivers normally accompany a network interface card. These drivers are often loaded on floppy disks, but are sometimes placed on compact discs; if the new computer does not have a CD reader installed, you might have to copy the drivers onto floppy disks using a computer that has a CD reader installed.
Install the network interface card in the appropriate slot and reconnect the computer cables. Also connect the network cable to the network interface card's connection jack. Start the computer and install the latest drivers after the computer is fully operational.
Before you can communicate with the network, you will have to install the appropriate communication protocols. This software can normally be found on the operating system's installation disks.
Test the completed installation by checking for network resources in whichever way is appropriate for the network.
The two Pentium computers should cause no problems, provided they have enough memory. Suggest upgrading to at least 64 MB of RAM if they do not meet that requirement.
The two 486 machines can provide a few more years of service. Extra memory here might make up for some lack of speed. You should also check closely to see what expansion slots are available for these computers.
The 286 computer must go. You might want to move one of the 486 computers to the Shipping Department and replace the computer in the Accounting Department.
All printers can be shared to the network, eliminating the requirement for the switch box. Unless the current printers are overworked, they are probably worth keeping. You might consider replacing the dot matrix printer, but not if the Shipping Department is printing forms. It is not possible to print multisheet forms on laser or ink jet printers.
Future machines should at least meet the minimum requirements for Windows NT. Remember that minimums aren't good enough. You should opt for at least 300 MHz and 64 MB of RAM. Also check the number of expansion slots available to ensure that you can add the necessary interface cards. Keep in mind that many lower-cost machines sacrifice expandability to keep the price low.
Circle the letter of the best answer for each of the following sentences: