Lesson 1: Connectivity Devices

What can you do to start the troubleshooting process?

The first step is to carry out a simple test on your hardware. Much complex equipment is microprocessor-driven hardware with built-in software. Simply by following the shut-down and restart procedure for these devices (sometimes this is a simple on-off switch) you can restart the equipment and restore it to proper functioning again.

If shutting down and restarting the entire system does not get the system running, call the service provider and ask it to test the T1 line and verify that it is correctly configured.

If neither of those two options solve the problem, you will need to contact your vendor and ask for help in troubleshooting the WAN equipment you have. Very few experienced systems engineers have the expertise needed to successfully troubleshoot this kind of scenario.

Lesson 2: Connection Services

1. Identify at least two network items in each branch-office network site that need upgrading.

Each site could upgrade to include the following:

New cabling: from 10 Mbps Ethernet to 100Mbp Category 5.
New cards: from 10 Mbps Ethernet to 100Base.
New architecture: from linear bus to star bus (100BaseT) with hubs.
2. The separate branch offices need to maintain voice and data communications with each other. Which type of WAN connection (link) might you use to connect the three sites to each other?

Use a T1 link, because it can carry voice and data simultaneously. (T1 is available through a carrier such as AT&T, MCI, Sprint, and others.) Note that E1 is a rough equivalent of T1 and is used outside the U.S.

3. Which type of device could be used to collect the multiple signals from voice and data and put them on the same WAN link?

A multiplexer mixes both types of signals and places them on the same WAN link.

4. Which type of connectivity device should be used to connect the LAN to the multiple paths in the WAN illustrated in the diagram above?

A router is the ideal device to connect the LAN to the multiple WAN paths. Routers can use multiple paths and can use best-path algorithms to determine the best path for each transmission.

1. An external modem is a small box that is connected to the computer by a ______________ cable running from the computer's port to the modem's computer-cable connection.

serial

2. The modem at the _______________ end converts digital signals into analog signals.

sending

3. Baud rate refers to the speed of oscillation of the _____________ _____________ on which a bit of data is carried.

sound wave

4. The bps can be greater than the __________ rate.

baud

5. Asynchronous transmission occurs over __________________ __________.

telephone lines

6. The Microcom Network Protocol (MNP) is a standard for asynchronous __________ - _____________ control.

data-error

7. In asynchronous communication, it is possible to double throughput by using ____________________ without having to pay for a faster channel speed.

compression

8. Synchronous communication relies on a _____________ scheme coordinated between two devices.

timing

9. More advanced, complex repeaters can act as multiport _________ to connect different types of media.

hubs

10. Repeaters do not have a __________________ function and so will pass along all data from one segment to the next.

filtering

11. A repeater takes a weak signal and ______________________ it.

regenerates

12. A repeater functions at the ________________ layer of the OSI reference model.

physical

13. If the volume of traffic from one or two computers or a single department is�flooding the network with data and slowing down the entire operation, a�________________ could isolate those computers or that department.

bridge

14. The bridge builds a routing table based on the ________________ addresses of computers that have sent traffic through the bridge.

source

15. Bridges work at the OSI __________ - _________ layer and, specifically, the _____________ ______________ ________________ sublayer.

data-link, Media Access Control

16. Bridges are often used in large networks that have widely dispersed segments joined by __________________ ___________.

telephone lines

17. Under spanning tree algorithm (STA), software can sense the existence of more than one _____________, determine which would be the most efficient, and then configure the bridge to use that one.

route

18. Bridges connect two segments and regenerate the signal at the ______________ level.

packet

19. Routers work at the _________________ layer of the OSI reference model.

network

20. Because they must perform complex functions on each packet, routers are _________________ than most bridges.

slower

21. Routers do not look at the destination node address; they look only at the _________________ address.

network

22. Unlike bridges, routers can accommodate multiple active ____________ between LAN segments and choose among them.

paths

23. The two major types of routers are ____________ and __________________.

static, dynamic

24. A brouter will ______________ nonroutable protocols.

bridge

25. Most often, gateways are dedicated ________________ on a network.

servers

26. The gateway takes the data from one environment, strips it, and repackages it in the __________________ ___________ from the destination system.

protocol stack

27. Gateways are ___________ specific, which means that they are dedicated to a particular type of transfer.

task

28. With the exception of ADSL, public telephone lines require users to _______________ make a connection for each communication session.

manually

29. The three factors an administrator must take into account when considering how best to implement communication between two modems are __________________, _______________, and __________.

throughput, distance, cost

30. Leased lines provide ___________________ connections that do not use a series of switches to complete the connection.

dedicated

31. A good remote-access option that offers stable lines for companies that are constantly communicating between networks is to use ______________ lines.

leased (dedicated)

32. The ____________ - _____ - _____________ _____________________ _ __________________ allows a remote client to establish a secure connection to the corporate LAN over the Internet and RAS.

Point-to-Point Tunneling Protocol

33. Because the PSTN was designed primarily for voice, _________ - _____ lines do not have the consistent quality required for secure data communications.

dial-up

34. A dedicated line is _______________ and more _______________ than a dial-up connection.

faster, reliable

35. One advantage that dedicated lines offer over dial-up lines is that the service company implements ____________ _______________________ to improve communication, thereby ensuring line quality.

line conditioning

36. Digital lines provide ______________ - ___ - _____________ synchronous communication.

point-to-point

37. Because DDS uses ________________ communication, it does not require modems.

digital

38. T1 uses a technology called ____________________ in which several signals from different sources are collected into a component and fed into one cable for transmission.

multiplexing

39. T1 can accommodate 24 ____________________ data transmissions over each two-wire pair.

simultaneous

40. Subscribers who do not need or cannot afford the bandwidth of an entire T1 line can subscribe to one or more T1 _________________.

channels

41. With packet switching, the data is broken down into packets, and each packet is tagged with a _____________________ _________________ and other information.

destination address

42. At the destination, the packets are _____________________ into the original message.

reassembled

43. Two packets from the original data package can arrive out of sequence because they followed different ____________ to reach the same destination.

paths

44. Virtual circuits are composed of a series of ________________ connections between the sending computer and the receiving computer.

logical

45. Because of its extensive ____________ _______________, X.25 can appear to be slow.

error checking

46. X.25 was originally developed for the __________________ environment.

mainframe

47. Frame-relay data travels from a network over a ________________ _________________ line to a data switch and into the frame-relay network.

digital leased

48. Frame-relay networks can also provide subscribers with __________________ as needed, which lets the customer make nearly any type of transmission.

bandwidth

49. Frame-relay networks are faster at performing basic ________________ - __________________ operations than are X.25 networks.

packet-switching

50. ATM is an advanced implementation of ______________ ______________ that provides high-speed data transmission rates.

packet switching

51. ATM transmits data in 53-byte _________ rather than variable-length frames.

cells

52. ATM switches are multiport devices that can act as either ____________ to�forward data from one computer to another within a network or _________________ to forward data at high speeds to remote networks.

hubs, routers

53. ATM uses switches as ___________________________ to permit several computers to put data on a network simultaneously.

multiplexers

54. ATM can be used with existing _____________ designed for other communications systems.

media

55. Basic Rate ISDN divides its available ________________ into three data channels.

bandwidth

56. FDDI is a specification that describes a high-speed (100 Mbps) token-ring LAN that uses ___________ - __________ media.

fiber-optic

57. FDDI can be used for __________________ networks to which other, low-capacity LANs can connect.

backbone

58. A computer on an FDDI network can transmit as many frames as it can produce within a predetermined time before letting the ____________ go.

token

59. Traffic in an FDDI network consists of two similar streams flowing in opposite directions around two counter-rotating ______________.

rings

60. An advantage of the dual-ring topology is ______________________.

redundancy

61. To isolate serious failures in the ring, FDDI uses a system called _________________ in which a computer that detects a fault sends a signal onto the network.

beaconing

Lesson 1: Choosing a Network Design

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:

1. A logical bus with a physical bus.
2. A logical bus with a physical star.

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.

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:

• Use thinnet coaxial cable to connect each computer in a series?

• Terminate both ends of the bus?

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.

Material Requirements

	Logical bus; physical bus	Logical bus; physical star
Type of Cable
Length of Cable
Connectors (type and count)
Terminators
Patch cables
Patch Panel
Hub

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.

Lesson 2: Establishing a Client/Server Environment

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:

• Where should the server be located?
• What additional materials are required?
• What compatibility issues might arise?

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.

Lesson 3: Working with Device Drivers and NICs

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.

Lesson 4: Ensuring Hardware Compatibility

1. Which resources do you anticipate are likely to present problems in the future and, therefore, should be upgraded or replaced?
2. What do you suggest as the minimum operational requirements for equipment to be acquired in the future?

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.

1. Using a peer-to-peer network implies that all computers on the network are ____________.

equal

2. One drawback to using a peer-to-peer network is ________________ _____________________.

limited performance

3. On a server-based network, resources are ___________________.

centralized

4. Before beginning to design a new network, you must take an inventory to determine what ________________ and _______________ you already have, as well as what you need to acquire.

hardware, software

5. Working with a drawing of the _______________ is the place to start when creating a map of the new network.

facility

Circle the letter of the best answer for each of the following sentences:

1. A driver is:

1. hardware.
2. a peripheral device.
3. a NIC.
4. software.

d.

2. In the networking environment, a NIC driver is needed to:

1. communicate with other NICs on a network.
2. communicate between the NIC and the computer's operating system.
3. communicate between the file server and the other computers on the network.
4. communicate between different types of computers on a network.

b.

3. Select the correct statement about printer drivers.

1. There is no universal printer driver that will ensure full functionality of all�printers.
2. Printers made by a specific printer manufacturer can always use the same printer driver and have full functionality.
3. There is a specific printer driver designed for every model of printer that can ensure the full functionality of that model of printer on all operating systems.
4. A laser-printer driver from one manufacturer will provide full functionality for all laser printers, regardless of the manufacturer.

a.

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