Netw202

TESTOUT OF NETW202
1.Which form of communication is a real-time, text-based communication type used between two or more people who use mostly text to communicate?
A. Weblogs
B. Wikis
C. Instant messaging
D. Podcasting

C. Instant messaging is the only answer that is both text based and real time.

2. Which type of network provides customers with limited access to corporate data such as inventory, parts lists, and orders?
A. Intranet
B. Extranet
C. Internetwork
D. Internet B. An extranet provides as-needed access for external vendors and customers to a secure corporate network. An intranet is for internal users.

3. Wikis are collaborative web pages created and edited by users. 4. What prioritizes traffic and its characteristics to manage data?
A. Network administration
B. Network traffic
C. QoS strategy
D. Network evaluation C. Considering the importance of traffic flow when managing data is a function of a quality of service (QoS) strategy. Network administrators would evaluate the network traffic to determine a QoS strategy.

5. Rules that govern the process of network communication are called protocols. 6. What network traffic processes must be in place for quality of service strategies to work correctly? (Choose two.)
A. Traffic is classified based on quality of service requirements.
B. Priorities are assigned to each classification of application data.
C. Web traffic is always assigned to a high-priority queue for processing.
D. Digital movies are always assigned to the high-priority queue for processing.
E. E-mail traffic is always assigned to the low-priority queue. A, B. A quality of service strategy first classifies traffic based on requirements and then assigns priorities to the classifications as needed by the owners of the network. The network administrator can give different priorities to e-mail, web traffic, and movies.

7. Copper cables and fiber-optic cables are two types of network media.

8. What are two components of network architecture? (Choose two.)
A. People that comprise the human network
B. Built-in growth potential
C. Data transfer across the network
D. Redundant technologies
E. Corporations that operate and maintain the data network
B, D. Two components of a network’s architecture are scalability, which is planning for growth, and fault tolerance, which includes redundant links. The other answers describe either users of the network or the product of it (data transfer).
9. Symbols that graphically represent network devices and media are called icons.
10. For which three reasons were circuit-switched, connection-oriented technologies rejected when the Internet was being developed? (Choose three.)
A. Circuit-switched technologies required that a single message be broken up into multiple message blocks that contain addressing information.
B. Early circuit-switched networks did not automatically establish alternative circuits in the event of circuit failure.
C. Circuit-switched technologies required that an open circuit between network endpoints be established even if data was not being actively transferred between locations.
D. The quality and consistency of messages transmitted across a connection-oriented, circuit-switched network cannot be guaranteed.
E. The establishment of simultaneous open circuits for fault tolerance is costly. B, C, and E. Circuit-switched networks did not automatically establish alternative circuits in the event of circuit failure and required that an open circuit between network endpoints be established, even if data was not being actively transferred between locations. Also, the establishment of simultaneous open circuits for fault tolerance is costly.

11. For which three reasons was a packet-switched, connectionless data communications technology used when developing the Internet? (Choose three.)
A. It can rapidly adapt to the loss of data transmission facilities.
B. It efficiently utilizes the network infrastructure to transfer data.
C. Data packets can travel multiple paths through the network simultaneously.
D. It allows billing of network use by the amount of time a connection is established.
E. It requires that a data circuit between the source and destination be established before data can be transferred.

A, B, C. Packet-switched, connectionless data communications technology can rapidly adapt to the loss of data transmission facilities and efficiently utilizes the network infrastructure to transfer data, and data packets can travel multiple paths through the network simultaneously. D and E refer to connections being established, which is not the nature of connectionless data communications.
12. A Router is a device that helps direct messages between networks
13. What is the role of QoS in a converged network?
A. Ensures that all traffic above available bandwidth levels is dropped
B. Establishes delivery priorities for different types of communication in a network
C. Determines precise priorities for all types of network communication
D. Allows unused bandwidth to be shared by other organizations within the network B. QoS establishes priorities for different communications. It is not required to rate all network communication, just to give priority to what is deemed important.

14. Which term describes a common platform for diverse communication types?
A. Scalability
B. Convergence
C. Fault tolerance
D. Quality of service B. Convergence is combining different technologies, such as telephone, video, and text, on one network platform.
15. Connectionless messages are broken into packets.
16. Which of the following pertains to network infrastructure security?
A. A competitor accesses sensitive information through an unsecured wireless network.
B. Builders accidentally cut a network cable while digging.
C. A disgruntled employee alters information in a customer database.
D. A secretary sends confidential information in a reply to an e-mail that falsely appears to come from her boss. B. Only the cut cable pertains to infrastructure security. The others refer to content security. The unsecured wireless network might be allowed in network plans, but care must be taken to keep sensitive information beyond its reach.

17. A worker is assigned to work on a project with another employee from a different city. During online meetings, there are periods of sketchy video and garbled voice communications. Which combination of the following conditions could cause this?
A. Poor scalability in network design
B. Poor security, allowing someone to download music and video files at work
C. Lack of redundant links to the firewall
D. Poor QoS

B, D. It is possible that music and video downloads could take too much bandwidth and processing, disrupting the conference. Better QoS would give the video session priority over the download and avoid disruption.
18. Which pair of terms describes a network communication in which a bank has 24-hour exclusive access to an ATM? (Choose one.)
A. Connectionless and packet-switched
B. Packet-switched and connection-oriented
C. Circuit-switched and connection-oriented
D. Circuit-switched and connectionless
C. The connection is established and exclusive, so it is privately circuit switched. Circuit-switched connections are connection oriented.

19. Which OSI layer is associated with IP addressing?
A. 1
B. 2
C. 3
D. 4 C. IP addressing is a concern of the OSI network layer (Layer 3). Physical addressing happens at OSI Layer 2.
20. The elements of communication include a message source, a message destination, and a channel, or medium, to transport the message. 21. Which type of addressing is found at the OSI Layer 2? (Choose two.)
A. Logical
B. Physical
C. MAC
D. IP
E. Port B, C. A MAC address is the physical address burned on to the OSI Layer 2 network interface card. Logical addressing happens at OSI Layer 3.

22. When a server responds to a web request, what occurs next in the encapsulation process after the web page data is formatted and separated into TCP segments?
A. The client decapsulates the segment and opens the web page.
B. The client adds the appropriate physical address to the segments so that the server can forward the data.
C. The server converts the data to bits for transport across the medium.
D. The server adds the source and destination IP address to each segment header to deliver the packets to the destination.
E. The server adds the source and destination physical addresses to the packet header.
D. Encapsulating into TCP segments occurs at OSI Layer 4, so the next encapsulation is at OSI Layer 3, which includes adding source and destination IP addresses to the segment headers and converting them into packets. Then the physical addressing is added and the data is converted to bits.
23. Which term describes a specific set of rules that determine the formatting of messages and the process of encapsulation used to forward data?
A. Segmentation
B. Protocol
C. Multiplexing
D. QoS
E. Reassembly B. A protocol describes a specific set of rules for communication, including message formatting and encapsulation.

24. A limited-use protocol owned by a company is considered to be proprietary.

25. Which one of the following is associated with Layer 4 of the OSI model?
A. IP
B. TCP
C. FTP
D. TFTP B. TCP has control features pertaining to OSI Layer 4, FTP is an application (Layer 7), and IP and TFTP are network layer protocols (Layer 3).
26. The device that connects a device to the media is called a/an NIC, or network interface card
27. Which of the following terms defines dividing data streams into smaller pieces suitable for transmission?
A. Protocol
B. Multiplexing
C. Segmentation
D. Encapsulation
C. Segmentation, which occurs at OSI Layer 4, is the correct answer.

28. A device that moves data between networks is a router

29. Which of the following is the process for interweaving multiple data streams onto one shared communication channel or network medium?
A. Multicasting
B. Multiplexing
C. Encapsulation
D. Multidirecting
B. Multiplexing is the correct term.
30.Which of the following is associated with the network layer?
A. IP address
B. Frames
C. MAC address
D. Physical addressing
A. IP addressing is an OSI Layer 3 function. All others are OSI Layer 2 functions.
31. Which of the following is the correct “top down” order of the OSI model?
A. Application, presentation, session, network, transport, data link, physical
B. Application, presentation, session, transport, network, data link, physical
C. Application, session, presentation, transport, network, data link, physical
D. Application, presentation, session, network, data link, transport, physical B. The correct order is application, presentation, session, transport, network, data link, physical.

32. Which layer of the OSI model is concerned with end-to-end message delivery over the network?
A. Network
B. Transport
C. Data link
D. Application
B. End-to-end message delivery is the concern of OSI Layer 4, the transport layer.
33. Which layers of the OSI model are combined into other layers of the TCP/IP model? (Choose all that apply.)
A. Network
B. Presentation
C. Internet
D. Data link
E. Application
F. Physical
G. Session
H. Network access
I. Transport
B, D, F, G. The OSI presentation and session layers are combined into the application layer of the TCP/IP model. The OSI data link and physical layers are combined into the network access layer of TCP/IP. The transport and network layers have parallel layers in TCP/IP.

34. Which of the following are true about LANs and WANs? (Choose two.)
A. LANs connect groups of networks using ISPs.
B. LANs consist of hosts communicating with logical addresses.
C. WANs connect groups of networks using TSPs.
D. WANs connect LANs.
E. Hosts on a LAN use physical addressing to communicate.
C, E. LANs are connected by WANs. WANs connect networks through telephone service providers (TSP). Logical addressing is used between networks, and physical addressing, or MAC addresses, are used inside LANs.

35. The application layer is ___________ of the OSI model.
A. Layer 1
B. Layer 3
C. Layer 4
D. Layer 7
D. Layer 7 is the application layer and its components: applications, services, and protocols.
36. The TCP/IP application layer consists roughly of which three OSI layers?
A. Application, session, transport
B. Application, presentation, session
C. Application, transport, network
D. Application, network, data link

B. The functionality of the TCP/IP application layer protocols fits roughly into the framework of the top three layers of the OSI model: application, presentation, and session.

37. HTTP is used to do which of the following?
A. Resolve Internet names to IP addresses
B. Provide remote access to servers and networking devices
C. Transfer files that make up the web pages of the World Wide Web
D. Transfer the mail messages and attachments

C. Hypertext Transfer Protocol (HTTP) is used to transfer files that make up the web pages of the World Wide Web. DNS is used to resolve Internet names to IP addresses, and Telnet is used to provide remote access to servers and networking devices.
38. Post Office Protocol (POP) uses which port?
A. TCP/UDP port 53
B. TCP port 80
C. TCP port 25
D. UDP port 110 D. Post Office Protocol (POP) uses UDP port 110.
39. What is GET?
A. A client request for data
B. A protocol that uploads resources or content to the web server
C. A protocol that uploads information to the server in plain text that can be intercepted and read
D. A response from a server
A. GET is a client request for data.

40. Which is the most popular network service?
A. HTTP
B. FTP
C. Telnet
D. E-mail

D. E-mail, the most popular network service, has revolutionized how people communicate through its simplicity and speed. Choice A. is incorrect, because HTTP is a protocol, not a service.

41. FTP requires 2 connection(s) between client and server to successfully transfer files.
A. 1
B. 2
C. 3
D. 4

B. To successfully transfer files, FTP requires two connections between the client and the server: one for commands and replies and another for the actual file transfer.

42. DHCP enables clients on a network to do which of the following?
A. Have unlimited telephone conversations
B. Play back video streams
C. Obtain IP addresses
D. Track intermittent denial of service attacks
C. The Dynamic Host Configuration Protocol (DHCP) enables clients on a network to obtain IP addresses and other information from a DHCP server.
43. The Linux and UNIX operating systems use SAMBA, which is a version of which protocol?
A. SMB
B. HTTP
C. FTP
D. SMTP

A. The Linux and UNIX operating systems provide a method of sharing resources with Microsoft networks using a version of SMB called SAMBA.
44. Which of the following is a connection using Telnet?
A. File Transfer Protocol (FTP) session
B. Trivial File Transfer Protocol (TFTP) session
C. Virtual Terminal (VTY) session
D. Auxiliary (AUX) session

C. A connection using Telnet is called a VTY session, or connection.

45. Is eBay a peer-to-peer or client/server application?

eBay is a client/server application. eBay is implemented as a web server that responds to web client (browser) requests using HTTP.
46. In the client/server model, the device requesting the service is referred to as the client

client. Even though a device can serve as a client and a server at times, the device requesting a service is defined as the client and the device providing the service is defined as the server.

47. HTTP is referred to as a request/response protocol. What are three typical message formats?
GET, PUT, and POST. GET is a request; PUT and POST provide uploading.
48. DHCP allows the automation of what?
Assignment of IP addresses, subnet masks, and default gateway. The protocol automates the assignment of IP addresses, subnet masks, gateway, and other IP networking parameters.
49. What does FTP stand for, and what is it used for?
FTP stands for File Transfer Protocol. It is used to move files on the network. FTP was developed to allow file transfers between a client and a server. An FTP client is an application that runs on a computer that is used to push and pull files from a server.

50. List the six-step process for converting human communications to data.
1. The user inputs data using a hardware interface.
2. The application layer prepares human communication for transmission over the data network.
3. Software and hardware convert data to a digital format.
4. Application services initiate the data transfer.
5. Each layer plays its role, and the OSI layers encapsulate data down the stack. Encapsulated data travels across the media to the destination. OSI layers at the destination decapsulate the data up the stack.
6. Data is ready to be processed by the end device.
51. Describe the two forms of application software and the purpose of each.
Application software has two forms: applications and services:
■ Applications are designed to interact with us. Application is software for the user. If the device is a computer, the application is typically initiated by the user. Although there can be many layers of support underneath, application software provides an interface between humans and the hardware. The application will initiate the data transfer process when the user clicks the Send button or performs a similar action.
■ Services are background programs that perform a particular function in the data network. Services are invoked by a device connecting to the network or by an application. For example, a network service can provide functions that transmit data or provide conversion of data in a network. In general, services are not directly accessible or seen by the end user. They provide the connection between an application and the network.
52. Elaborate on the meaning of the terms server and client in the context of data networks.

The source end of data communication is referred to as the server, and the receiving end is called the client. The client and server processes are application layer services that provide the foundation for data network connectivity.
In some cases, the servers and clients are devices that perform that role specifically and exclusively. For example:
■ A central file server can contain an organization’s business data files that employees access using their client-only workstation.
■ Internet-based examples include web servers and mail servers, where many users access a centrally provided service.
■ In other situations, such as file sharing over a home network, individual devices can perform both server and client roles at different times.
Servers are both a repository and a source of information such as text files, databases, pictures, video, or audio files that have been previously recorded.
Client processes at the other end of the communication across the data network allow the user to make requests to obtain the data from a server. The client software typically uses a program initiated by a user. The client initiates communication data flow from the server by sending requests for the data to the server. The server responds by starting to send one or more streams of data to the client. In addition to the actual data transfer, this exchange can include user authentication and identification of the data file to be transferred.
Examples of common client/server services include the following:
■ DNS (Domain Name Service)
■ FTP
■ HTTP
■ Telnet (Teletype Network Service)
53. Compare and contrast client/server with peer-to-peer data transfer over networks.

Client/server data transfer specifically refers to the centralized source end of data communication as the server and the receiving end as the client.
With peer-to-peer data transfer, both client and server services are used within the same conversation. Either end of the communication can initiate the exchange, and both devices are considered equal in the communication process. The devices on either end of the communication are called peers.
In contrast to a client/server model, where a server is typically a centralized repository and responds to requests from many clients, peer-to-peer networking has distributed data. Furthermore, after the communication is established, the peers communicated directly; the data is not processed at the application layer by a third device on the network.
54. Functions specified by application layer protocols include
■ The processes that are to occur at either end of the communication. This includes what has to happen to the data and how the data is to be structured.
■ The types of messages. These can include requests, acknowledgments, data messages, status messages, and error messages.
■ The syntax of the message. This gives the expected order of information (fields) in a message.
■ The meaning of the fields within specific message types. The meaning has to be constant so that the services can correctly act in accordance with the information.
■ The message dialogs. This determines which messages elicit which responses so that the correct services are invoked and the data transfer occurs.
55. DNS, HTTP, SMB, and SMTP/POP use a client/server process.
■ Domain Name System (DNS) provides users with an automated service that matches or resolves resource names and e-mail domains with the required numeric device network addresses. This service is available to any user connected to the Internet and running an application layer application such as a web browser or e-mail client program.
■ HTTP was originally developed to publish and retrieve HTML pages and is now used for distributed, collaborative, hypermedia information systems. HTTP is used by the World Wide Web (WWW) to transfer data from web servers to web clients.
■ Server Message Block (SMB) describes the structure of sharing network resources, such as directories, files, printers, and serial ports, between computers.
■ Simple Mail Transport Protocol (SMTP) transfers outbound e-mails from the e-mail client to the e-mail server and transports e-mail between e-mail servers and so enables e-mail to be exchanged over the Internet.
■ POP, or POP3 (Post Office Protocol version 3), delivers e-mail from the e-mail server to the client.
56. DNS includes standard queries, responses, and data formats. DNS protocol communications are carried in a single format called a message. This message format is used for all types of client queries and server responses, for error messages, and for the transfer of resource record information between servers.
HTTP is a request/response protocol:
■ A client application layer application, typically a web browser, sends a request message to the server.
■ The server responds with the appropriate message.
HTTP also includes messages to upload data to the server, such as when completing an online form.
SMB messages use a common format to
■ Start, authenticate, and terminate sessions
■ Control file and printer access
■ Allow an application to send or receive messages to or from another device
SMTP specifies commands and replies that relate to session initiation, mail transaction, forwarding mail, verifying mailbox names, expanding mailing lists, and the opening and closing exchanges.
POP is a typical client/server protocol, with the server listening for client connections and the client initiating the connection to the server. The server can then transfer the e-mail.
DNS, HTTP, SMB, and SMTP/POP use client/server, request/response messages. Whereas users see the applications that use HTTP (a web browser), SMB (file manager), and SMTP/POP (e-mail client), a DNS operation underlies these applications and is truly transparent to the user.
57. Which port number is used by HTTP?
A. 23
B. 80
C. 53
D. 110

B. Port 80 is the standard port number used with HTTP. Port 23 is Telnet, port 20 is FTP, and port 110 is POP3.
58. Which port number is used with SMTP?
A. 20
B. 23
C. 25
D. 143

C. Port number 25 is used for SMTP.
59. Which characteristics are part of TCP? (Choose two.)
A. Reliable
B. Connectionless
C. No flow control
D. Resends anything not received

A, D. TCP is a reliable, connection-oriented protocol.
60. At the transport layer, which of the following controls is used to keep a transmitting host from overflowing the buffers of a receiving host?
A. Best effort
B. Encryption
C. Flow control
D. Congestion avoidance

C. TCP uses flow control to avoid buffer overflows.
61. End systems use port numbers to select the proper application. What is the lowest port number that can be dynamically assigned by the host system?
A. 1
B. 128
C. 256
D. 1024

D. Port numbers 0 to 1023 are the well-known () ports. Port numbers 1024 to 49151 are the registered ports and are used by the host for dynamic port allocation. Port numbers 49152 to 65535 are the private and dynamic ports.
62. During data transfer, what is the receiving host responsible for? (Choose the best two answers.)
A. Encapsulation
B. Bandwidth
C. Segmentation
D. Acknowledgment
E. Reassembly

D, E. The receiving host has to acknowledge receipt of the packets and then reassemble them in the right order.
63. What are the transport layer’s responsibilities?

Answers could vary and could include (a) keeping track of the individual conversations taking place between applications on the source and destination hosts, (b) segmenting data and adding a header to identify and manage each segment, (c) using the header information to reassemble the segments into application data, and (d) passing the assembled data to the correct application.
64. Why does TCP use a sequence number in the header?
A. To reassemble the segments into data B. To identify the application layer protocol
C. To indicate the number of the next expected byte
D. To show the maximum number of bytes allowed during a session

A. Sequence numbers are used in the TCP headers because segments could arrive at their destination in a different order than when they were sent. The numbers allow the receiving host to reassemble them in the proper order.
65. Which of the following determines how much data a sending host running TCP/IP can transmit before it must receive an acknowledgment?
A. Segment size
B. Transmission rate
C. Bandwidth
D. Window size

D.In TCP, window size is used to manage flow control.
66. What is the purpose of TCP/UDP port numbers?
A. To indicate the beginning of a three-way handshake
B. To reassemble the segments into the correct order
C. To identify the number of data packets that can be sent without acknowledgment
D. To track the different conversations crossing the network at the same time D. Port numbers allow you to track multiple conversations generated by the same host using the same IP address
67. What does segmentation provide to communications?

Segmentation of the data, in accordance with transport layer protocols, provides the means to both send and receive data when running multiple applications concurrently on a computer.

68. In networking terms, what is reliability? Reliability means ensuring that each segment that the source sends arrives at the destination. 69. List three network applications that use TCP. Web browsing, e-mail, file transfer.
70. List three network applications that use UDP
DNS, video streaming, Voice over IP (VoIP).

71. What is contained in the header of each segment or datagram?
The source and destination port number.
72. What is the purpose of sequence numbers?
A sequence number allows the transport layer function on the destination host to reassemble segments in the order in which they were transmitted.
73. Which acknowledgment number should be sent by the receiver shown in Figure 4-18?

7. The acknowledgment number is always one more than the last segment received.
74. What is the protocol number for UDP?
A. 1
B. 3
C. 6
D. 17

D. A flag is set in the segment header. If this flag actually reads 17, it is identified as a UDP header.
75. What is the default DNS port number?
A. 1025
B. 53
C. 110
D. 143

B. Port 53 is used for DNS.
76. What is the netstat utility used for on a host?
Netstat lists the protocol in use, the local address and port number, the foreign address and port number, and the state of the connection. Netstat also displays active TCP connections, ports on which the computer is listening, Ethernet statistics, the IP routing table, IPv4 statistics (for IP, ICMP, TCP, and UDP), and IPv6 statistics (for IPv6, ICMPv6, TCP over IPv6, and UDP over IPv6). Used without parameters, the netstat command displays active TCP connections.
77. Explain an expectational acknowledgment.

TCP uses the acknowledgment number in segments sent back to the source to indicate the next byte in this session that the receiver expects to receive.
78. Which protocol provides connectionless network layer services?
A. IP
B. TCP
C. UDB
D. OSI

A. IP provides connectionless network layer services. TCP is connection oriented. UDP is connectionless, but it works at the transport layer.
79. What two commands can be used to view a host’s routing table?

netstat -r and route print.
80. Select three pieces of information about a route that a routing table contains.
A. Next-hop
B. Source address
C. Metric
D. Destination network address
A, C, D. A routing table contains the next-hop, metric, and destination network address. Routers do not need the source address, last hop, or default gateway to find a path to a network.
81. What kinds of problems are caused by excessive broadcast traffic on a network segment? (Choose three.)
A. Consumes network bandwidth
B. Increases overhead on network
C. Requires complex address schemes
D. Interrupts other host functions
E. Divides networks based on ownership
F. Advanced hardware required

A, B, D. Reduced network bandwidth, increased overhead, and reduced host functions are three potential results of excessive broadcasts. The other answers can be part of a solution to the problem of excessive broadcasts.
82. What are three key factors to consider when grouping hosts into a common network?

Purpose, ownership, and geographic location are three key ways to divide a network.
83. Which of the following are not functions of the network layer? (Choose two.)
A. Routing
B. Addressing packets with an IP address
C. Delivery reliability
D. Application data analysis
E. Encapsulation
F. Decapsulation

C, D. Delivery reliability is a transport layer concern. Application data analysis is a concern of the presentation layer. Routing, addressing packets with an IP address, encapsulation, and decapsulation are functions of the network layer.
84. Which of the following are true about IP? (Choose two.)
A. IP stands for International Protocol.
B. It is the most common network layer protocol.
C. It analyzes presentation layer data.
D. It operates at OSI Layer 2.
E. It encapsulates transport layer segments.

B, E. IP stands for the Internet Protocol, which operates at OSI Layer 3 (the network layer). IP encapsulates transport layer segments. IP does not look inside the upper-level PDU, so it has no knowledge of the presentation layer data.
85. What is the name of the process of removing the OSI Layer 2 information from an IP packet?

Decapsulation.
86. Which of the following is true about IP?
A. It is connection oriented.
B. It uses application data to determine the best path.
C. It is used by both routers and hosts.
D. It is reliable.

C. Routers and hosts use IP. B is incorrect because IP uses addressing information in the header to determine the best path for a packet. D is incorrect because IP is a “best effort” unreliable protocol.
87. Which of the following are true about network layer encapsulation? (Choose two.)
A. It adds a header to a segment.
B. It can happen many times on the path to the destination host.
C. It is performed by the last router on the path.
D. Both source and destination IP addresses are added.
E. It converts transport layer information into a frame.

A, D. Network layer encapsulation adds a header to a segment and adds both source and destination IP addresses. Network layer encapsulation happens only on the original host; other devices can read the data, but they do not remove or alter it until the destination network is reached. The network layer converts transport layer segments into packets.
88. Which of the following are true about TCP and IP? (Choose two.)
A. TCP is connectionless and IP is connection oriented.
B. TCP is reliable and IP is unreliable.
C. IP is connectionless and TCP is connection oriented.
D. TCP is unreliable and IP is reliable.
E. IP operates at the transport layer.

B, C. TCP is reliable and connection oriented. IP is unreliable and connectionless. IP operates at the network layer.
89. Why is IP “media independent”?
A. It encapsulates Layer 1 instructions.
B. It works the same on all Layer 1 media.
C. It carries both video and voice data.
D. It works without Layer 1 media.

B. IP encapsulates OSI Layer 4 data. IP can carry voice, video, and other types of data, but “media independent” refers to the OSI Layer 1 medium that carries the data across the networks. IP, or any other communication, can occur without a physical (OSI Layer 1) medium.
90. TCP is a transport layer protocol.

91. How many bits are in an IPv4 address?
32. There are four octets (8 bits each) in an IPv4 address.
92. Which of the following are true about static and dynamic routing? (Choose two.)
A. Static routing requires a routing protocol such as RIP.
B. A default route is a dynamic route.
C. Dynamic routing adds packet-processing overhead.
D. Administrative overhead is reduced with static routing.
E. Routers can use static and dynamic routing simultaneously.

C, E. Dynamic routing adds packet-processing overhead, and routers can use static and dynamic routing simultaneously. Static routing does not require a routing protocol. A default route is an example of a static route. Because static routes must be manually configured and updated, they add to administrative overhead.
93. What can happen when the TTL is 1? (Choose two.)
A. The packet can be successfully delivered if it is destined for a directly connected network.
B. TCP controls in the packet will add hops to the TTL.
C. The packet will be dropped by the next router unless that router has an interface on the destination network.
D. The packet will be returned to the source host.
E. The packet will be returned to the previous router.

A, C. When the TTL is 1, it has one hop remaining to be either delivered or discarded. IP does not provide return notification of dropped packets. TCP controls at the destination will request a packet retransmission, but the TCP PDU is never accessed en route.
94. IP is connectionless and will occasionally drop a packet en route to a destination IP address. If packets are dropped, how will messages be completed?
A. Only the IP portion of the packet is dropped, but the TCP portion continues to the last router.
B. The routing protocols will carry the TCP information to the previous-hop router, which sends a reverse notification to the source.
C. The routing protocols, such as RIP, are connection oriented and will contact the source host.
D. The destination host is expecting the packet and will send a request if it does not arrive.
E. The IP header contains the source address so that the packet can be returned by the router that receives the packet when the TTL is 0.

D. The destination host will send a request if the packet does not arrive. IP is connectionless, so there is no reliability built into the protocol. Previous packets with TCP information have arrived at the destination host with “expectational” information. Routing protocols, such as RIP, are used by routers to share route information; they are not involved in TCP/IP reliability.
95. Which IP addresses are network addresses? (Choose two.)
A. 64.104.3.7 /28
B. 192.168.12.64 /26
C. 192.135.12.191 /26
D. 198.18.12.16 /28
E. 209.165.200.254 /27
F. 220.12.12.33/27

B, D. 192.168.12.64 /26 and 198.18.12.16 /28 are network addresses.
96. A network administrator is building a network for a small business that has 22 hosts. The ISP has assigned only one Internet routable IP address. Which IP address block can the network administrator use to address the network?
A. 10.11.12.16 /28
B. 172.31.255.128 /27
C. 192.168.1.0 /28
D. 209.165.202.128 /27

B. 172.31.255.128 /27
97. What subnet mask would be used with the hosts in the 128.107.176.0 /22 network?
A. 255.0.0.0
B. 255.248.0.0
C. 255.255.252.0
D. 255.255.255.0
E. 255.255.255.252

C. 255.255.252.0
98. You have been assigned the address block 10.255.255.224 /28 to create the network addresses for point-to-point WAN links. How many of these WANs can you support with this address block?
A. 1
B. 4
C. 7
D. 14

B. The four networks are .224, .228, .232, and .236.
99. What defines an IPv4 logical network?

Hosts with the same network portion of their IPv4 address.
100. Name and state the purpose of the three types of IPv4 addresses.

The three types of IPv4 addresses are
■ Network address: The address by which you refer to the network
■ Broadcast address: A special address used to send data to all hosts in the network
■ Host addresses: The addresses assigned to the end devices in the network
101. A network administrator needs to create a new network that has 14 computers and two router interfaces. What subnet mask will provide the appropriate number of IPv4 addresses for this network with minimal wasted addresses?
A. 255.255.255.128
B. 255.255.255.192
C. 255.255.255.224
D. 255.255.255.240
E. 255.255.255.248
F. 255.255.255.252

C. 255.255.255.224 provides the 16 addresses required. .224 will provide 30. .240 will provide only 14.

102. What distinguishes each of the three types of IPv4 addresses?

The three types of IPv4 addresses are
■ Network address: Lowest address in the network 0 for each host bit in the host portion of the address.
■ Host address: Host bits are a unique mix of 1s and 0s within a network.
■ Broadcast address: Uses the highest address in the network range. The host portion is all 1s.
103. List the three forms of IPv4 communication.
Following are the three forms of IPv4 communication:
■ Unicast: The process of sending a packet from one host to an individual host
■ Broadcast: The process of sending a packet from one host to all hosts in the network
■ Multicast: The process of sending a packet from one host to a selected group of hosts
104. List the purpose of having specified ranges of IPv4 addresses for public and private use.

Specified private addresses allow network administrators to allocate addresses to those hosts that do not need to access the Internet.
105. A host in the south branch cannot access the server with the address 192.168.254.222 /224. While examining the host, you determine that its IPv4 address is 169.254.11.15 /16. What is the apparent problem?
A. The host is using a link-local address.
B. The server is using an invalid subnet mask.
C. The host has been assigned a broadcast address.
D. The server thinks that the host is on the logical network with the server.

A. The host is using a link-local address. Link-local addresses should not be routed.
106. List three reasons for planning and documenting IPv4 addresses.

The allocation of addresses inside the networks should be planned and documented for the following purposes:
■ Preventing duplication of addresses
■ Providing and controlling access
■ Monitoring security and performance
107. Cite examples where network administrators should statically assign IPv4 addresses.

Administrators should statically assign addresses to servers, printers, LAN gateway addresses on routers, management addresses on network devices such as switches, and wireless access points.
108. What was the primary motivation for the development of IPv6?

Running out of IPv4 addresses is the primary motivation for developing IPv6.
109. What is the purpose of the subnet mask in IPv4 addressing?

Network devices use the subnet mask to determine the network or subnet address of an IP address that the device is processing. 110. List factors to consider when planning an IPv4 addressing scheme.
Networks are subnetted to overcome issues with location, size, and control. In designing the addressing, consider these factors for grouping the hosts:
■ Grouping based on common geographic location
■ Grouping hosts used for specific purposes
■ Grouping based on ownership
111. What are three tests that use the ping utility to test and verify the operation of a host?

Three tests that use the ping utility are
■ Ping 127.0.0.1: Loopback test to test IP operation
■ Ping the host gateway address or another host on the same network: To determine communication over the local network
■ Ping a host on a remote network: Test device default gateway and beyond
Challenge Questions and Activities
112. What are the reserved and special IPv4 addresses, and how are they used?

The reserved and special IPv4 addresses are
■ Multicast addresses: Reserved for special purposes is the IPv4 multicast address range 224.0.0.0 to 239.255.255.255.
■ Private addresses: The private address blocks are
■ 10.0.0.0 to 10.255.255.255 (10.0.0.0 /8)
■ 172.16.0.0 to 172.31.255.255 (172.16.0.0 /12)
■ 192.168.0.0 to 192.168.255.255 (192.168.0.0 /16)
Private space address blocks are set aside for use in private networks. Packets using these addresses as the source or destination should not appear on the public Internet. The router or firewall device at the perimeter of these private networks must block or translate these addresses.
■ Default route: The IPv4 default route is 0.0.0.0. The use of this address reserves all addresses in the 0.0.0.0 to 0.255.255.255 (0.0.0.0 /8) address block.
■ Loopback: The IPv4 loopback address 127.0.0.1 is a reserved address. Addresses 127.0.0.0 to 127.255.255.255 are reserved for loopback, where hosts direct traffic to themselves.
■ Link-local addresses: IPv4 addresses in the address block 169.254.0.0 to 169.254.255.255 (169.254.0.0 /16) are designated as link-local addresses. These addresses can be automatically assigned to the local host by the operating system in environments where no IP configuration is available. These might be used in a small peer-to-peer network or for a host that could not automatically obtain an address from a Dynamic Host Configuration Protocol (DHCP) server.
■ Test-net addresses: The address block 192.0.2.0 to 192.0.2.255 (192.0.2.0 /24) is set aside for teaching and learning purposes. These addresses can be used in documentation and network examples. Unlike the experimental addresses, network devices will accept these addresses in their configurations.
113. Why is ICMPv4 an important protocol to have operating with IPv4? What are the ICMP message types?

IPv4 is an unreliable best-effort protocol. ICMPv4 provides a means for network problems such as dropped packets or congestion to be reported to the source network or host. Messages include
■ Host Conformation
■ Unreachable Destination or Service
■ Time Exceeded
■ Route Redirection
■ Source Quench
114. How does the data link layer prepare packets for transmission?
The data link layer prepares a packet for transport across the local media by encapsulating it with a header and a trailer to create a frame.
115. Describe four general data link layer media access methods. Suggest data communications environments in which these access methods can be appropriately implemented.
MAC methods for shared media are as follows:
■ Controlled: Each node has its own time to use the medium, a ring topology
■ Contention-based: All nodes compete for the use of the medium, a bus topology
Media access control in point-to-point connections can be one of the following:
■ Half duplex: A node can only transmit or receive at one time.
■ Full duplex: A node can both transmit and receive at the same time.
116. Describe the features of a logical ring topology.
In a logical ring topology, each node in turn receives a frame. If the frame is not addressed to a node, the frame is passed to the next node. If there is no data being transmitted, a signal (known as a token) can be placed on the media. A node can place a frame on the media only when it has the token. This is a controlled media access control technique called token passing.
117. Name five Layer 2 protocols.
Layer 2 protocols include
■ Ethernet
■ PPP
■ High-Level Data Link Control (HDLC)
■ Frame Relay
■ ATM
118. List five header field types in data link frames.
Typical frame header fields include
■ Start Frame field: Indicates the beginning of the frame
■ Source and Destination address fields: Indicate the source and destination nodes on the media
■ Priority/Quality of Service field: Indicates a particular type of communication service for processing
■ Type field: Indicates the upper-layer service contained in the frame
■ Logical connection control field: Used to establish a logical connection between nodes
■ Physical link control field: Used to establish the media link
■ Flow control field: Used to start and stop traffic over the media
■ Congestion control field: Indicates congestion in the media
119. If a node receives a frame and the calculated CRC does not match the CRC in the FCS, what action will the node take?
A. Drop the frame
B. Reconstruct the frame from the CRC
C. Forward the frame as it is to the next host
D. Disable the interface on which the frame arrives
A. The node drops the frame. The CRC provides error detection, not error correction, so B is incorrect. C is incorrect because the frame is not forwarded. The interface is not disabled, so D is incorrect.
120. If a node receives a frame and the calculated CRC does not match the CRC in the FCS, what action will the node take?
A. Drop the frame
B. Reconstruct the frame from the CRC
C. Forward the frame as it is to the next host
D. Disable the interface on which the frame arrives
C, D. PPP and HDLC are designed as WAN protocols. 802.11 and Ethernet are LAN protocols, so A and B are incorrect.
121.What are the contents of the data field in a frame?
A. 64 bytes
B. The network layer PDU
C. The Layer 2 source address
D. The data directly from the application that generated the data
B. The network layer PDU is encapsulated in the frame. The number of bytes in the payload is variable, so A is incorrect. C is incorrect because the Layer 2 source address is in the address field of the frame header. The data from the application undergoes encapsulation before being passed down to the data link layer, so D is incorrect.
122. Which of the following is a characteristic of contention-based MAC?
A. Used on nonshared media.
B. Nodes compete for the use of the medium.
C. Leaves MAC to the upper layer.
D. Each node has a specific time to use the medium.
B. Nodes compete for the media. Option A is incorrect because contention-based is used on shared media. C is incorrect because one of the primary purposes of Layer 2 is MAC. D is incorrect because taking turns is a function of controlled access.
123. Which of the following are common data link sublayers used in LANs? (Choose two.)
A. Protocol data unit
B. Logic Link Control
C. MAC
D. Network interface card
E. Carrier access multiaccess
B, C. LLC is the upper sublayer, and MAC is the lower sublayer.
124. Which of the following describes a virtual circuit?
A. Is an error-detection technique
B. Provides an encapsulation technique
C. Is used only with point-to-point physical topologies
D. Establishes a logical connection between two network devices
D. Virtual circuits establish a logical connection between two devices to provide a logical point-to-point topology. Option A is incorrect because CRC is an error-detection technique. Virtual circuits do not provide an encapsulation technique, so B is incorrect. C is incorrect because virtual circuits can be used over multiple types of physical topologies.
125. Name three basic parts that are common to all data link layer frames.
Header, data, and trailer.
126. Which of the following functions does the data link layer perform?
A. Provides user interfaces
B. Ensures end-to-end delivery of data between hosts
C. Connects the network software to the network hardware
D. Establishes and maintains sessions between applications
C. The data link layer provides the connection between hardware and software. A is incorrect; this is a role of the application layer. B is incorrect; this is a function of the network layer. D is incorrect; this is a function of the transport layer.
127. Which of the following is true about the logical topology of a network?
A. Is always multiaccess
B. Provides the physical addressing
C. Is determined by how the nodes in the network are connected
D. Influences the type of MAC used in the network
D. The logical topology influences MAC. The logical topology can be many types of MAC, so A is incorrect. The MAC sublayer provides the physical address, so B is incorrect. The logical and physical topologies are not always the same, so C is incorrect.
128. Explain the purpose of the Frame Check Sequence field in a data link frame trailer.
The media is a potentially unsafe environment for data. The signals on the media could be subject to interference, distortion, or loss that would substantially change the bit values that those signals represent. To ensure that the content of the received frame at the destination matches that of the frame that left the source node, a transmitting node creates a logical summary of the contents of the frame. This is known as the Frame Check Sequence (FCS) and is placed in the trailer to represent the contents of the frame.
When the frame arrives at the destination node, the receiving node calculates its own logical summary, or FCS, of the frame. The receiving node compares the two FCS values. If the two values are the same, the frame is considered to have arrived as transmitted. If the FCS values differ, the frame is discarded.
There is always the small possibility that a frame with a good FCS result is actually corrupt. Errors in bits can cancel each other out when the FCS is calculated. Upper-layer protocols would then be required to detect and correct this data loss.
129. How do data link layer addresses differ from network layer addresses?
Unlike Layer 3 logical addresses that are hierarchical, physical addresses do not indicate on what network the device is located. If the device is moved to another network or subnet, it will still function with the same Layer 2 physical address.
Because the frame is only used to transport data between nodes across the local media, the data link layer address is only used for local delivery. Addresses at this layer have no meaning beyond the local network. Compare this to Layer 3, where addresses in the packet header are carried from source host to destination host, regardless of the number of network hops along the route.
130. Compare and contrast the logical point-to-point and logical multiaccess topologies.
A logical point-to-point topology connects two nodes directly. In data networks with point-to-point topologies, the MAC protocol can be very simple. All frames on the media can only travel to or from the two nodes. The frames are placed on the media by the node at one end and taken off the media by the node at the other end. In point-to-point networks, if data can only flow in one direction at a time, it is operating as a half-duplex link. If data can successfully flow across the link from each node simultaneously, it is a full-duplex service.
A logical multiaccess topology enables a number of nodes to communicate by using the same shared media. Data from only one node can be placed on the medium at any one time. Every node sees all the frames that are on the medium, but only the node to which the frame is addressed processes the contents of the frame. Having many nodes share access to the medium requires a data link MAC method to regulate the transmission of data and thereby reduce collisions between different signals.
131. Describe the issues in a router when it is interconnecting interfaces of different speeds, such as connecting an Ethernet network to a WAN on a serial interface.
If a router is interfacing media of different speeds, the router will have to buffer the frames for transmission. If not enough buffers are available, the packets can be lost.
132. Discuss the purpose of including a source address in the frame header. Could just one Layer 2 address be used? If so, how? Are there any data link layer protocols that use a single address?
The source addresses are used to identify the source node. In most cases, Layer 2 source addresses are not used. The most common use of source addresses is for security or by switches learning where the host exists. The source address is also used in the creation of dynamic maps such as ARP.
Both ATM and Frame Relay use a single address in the frame header. These technologies use a single number that represents a connection.
133. Discuss the possible effect on throughput if a communication is operating in full duplex. Compare full duplex to multiaccess and half duplex.
The full-duplex communication between the two nodes could have twice the throughput of half-duplex and more than twice the throughput of multiaccess. If the underlying physical media can support it, the two nodes might be able to transmit and receive at full media bandwidth at the same time. This would be twice that of half duplex. Because multiaccess has overhead to control media access, the throughput is less than the bandwidth and, in many cases, much less. This would allow full duplex to have more than twice the throughput of multiaccess.
134.Describe how the router can use different frame formats to forward an IP packet. As the router receives a frame on one interface, it decapsulates the frame down to a packet. It then refers to the routing table to determine out which interface the packet should be forwarded. The router then will encapsulate the packet into a frame of the appropriate size for the segment connected to the outbound interface.
135. Copper cable and fiber-optic cable are examples of physical media, which is used to carry the communication signal.

136. What is the purpose of encoding?
A. To identify the start and stop bits in a frame
B. To denote the physical layer’s connectors of computers in relation to the way they connect to network media
C. To control the way frames are placed on the media at the data link layer
D. To represent the data bits by using different voltages, light patterns, or electromagnetic waves as they are placed onto the physical media
D. Encoding represents the data bits by using different voltages, light patterns, or electromagnetic waves as they are placed onto the physical media.
137. What two signaling methods use voltage to encode bits?
NRZ (nonreturn to zero) and Manchester
138. What best describes the purpose of the physical layer?
A. Ensures reliable transmission of data across a physical link
B. Determines connectivity and path selection between two end systems
C. Establishes the physical addressing, networking topology, and media access
D. Defines the functional specifications for links between end systems and the electrical, optical, and radio signals
D. The chief purpose of the physical layer is to define the functional specifications for links between end systems and the electrical, optical, and radio signals that carry data. Reliability, path selection, and media access are the tasks of other layers.
139.What is the most common UTP connector type?
RJ-45
140. Through what process does UTP cable help to avoid crosstalk?
A. Shielding of cable
B. Twisting of pairs
C. Grounding the endpoints
D. Cladding in cable
B. Crosstalk is reduced by the twisting of cables in the UTP (unshielded twisted-pair) cable. UTP has no cladding, shielding, or grounding points.
151. What is the required order of wires in a connector called? pinout
152. What are the advantages of using fiber-optic cable over copper cable? (Choose three.)
A. Copper is more expensive
B. Immunity to electromagnetic interference
C. Careful cable handling
D. Longer maximum cable length
E. Efficient electrical current transfer
F. Greater bandwidth potential
B, D, F. The advantages of using fiber-optic cabling include immunity to electromagnetic interference, longer maximum cable length, greater bandwidth reception and decoding requirements, and antenna design.
153. The physical media most susceptible to security breaches is wireless. Because wireless is open to anyone with a wireless receiver, it is more susceptible to security breaches than copper or fiber-optic media.
154. What is the purpose of cladding in fiber-optic cables?
A. Cable grounding
B. Noise cancellation
C. Prevention of light loss
D. EMI protection
C. Cladding helps prevent light loss. No other listed functions pertain to fiber-optic cable.
155. Which two of the following are true about straight-through cables?
A. They work in Cisco console ports.
B. They can be either 568A or 568B.
C. They can connect a host to a switch.
D. They can connect two switches. B, C. Rollovers work in Cisco console ports, and crossovers would connect two switches.
156. A rollover cable is also known as a Cisco cable because it is generally used as a connection to Cisco equipment.
157. Which of the following measures the actual data transfer rate over a medium?
A. Bandwidth
B. Output
C. Throughput
D. Goodput
C. Throughput measures actual data rates. Bandwidth is the line capacity, and goodput measures only the rate of usable application layer data bits that arrive.
158. Which of the following is NOT true?
A. 1 Gbps = 1,000,000,000 bits per second
B. 1 kbps = 1000 bits per second
C. 1 Mbps = 100,000 bits per second
D. 1 Tbps = 1,000,000,000,000 bits per second
C. 1 Mbps = 1,000,000 (106) bps
159. What is synchronization?
A. Keeping the correct time of day on all network machines
B. The timing mechanism devices use when transmitting data
C. Devices processing bits to the data link layer at the same speed
D. Constant bit times throughout the network
B. Synchronization between devices allows them to know when frames begin and end.
160. What is true about “bit time”?
A. It is the time it takes to encapsulate application data into a bit segment.
B. It is the time it takes for a NIC to move a bit from the data link layer to the Layer 1 media.
C. IEEE standards require it to be the same on all NICs.
D. It is the time it takes for a byte to traverse the copper or fiber cable.
B. Bit time changes depending on the speed of the NIC. The time it takes a bit to traverse the network is slot time (which counts bits, not bytes).
161. A user has a peer-to-peer network with two directly connected hosts. To add a third host, the user installs a hub and adds two straight-through cables so that each computer has its own connection to the hub. What will be the result of this network upgrade?
A. All three hosts will link to the hub.
B. Two hosts will link to the hub.
C. One host will link to the hub.
D. None of the hosts will link to the hub.
B. The two hosts with straight-through cables will link to the hub. The third host is using the original cable, which is a crossover cable appropriate for peer-to-peer connections, but will not link to a hub from a host.
162. A network administrator for a small wood products manufacturing company has throughput issues in the A wing of her building. The network devices are the same for all wings, and all appear to be performing normally, but the throughput has become consistently significantly lower in the A wing. Sales orders are up, and the machines on the production floor are working to full capacity. The administrator is under pressure to get throughput up to acceptable speed. In researching the problem, she determines the following list of facts. Which three of them are most likely to be contributing factors to the poor network performance?
A. The A wing has the largest number of hosts connected to the network.
B. The janitor buffs the floor of that wing at 4:00 p.m. Wednesdays. The other wings are buffed at night.
C. Some employees in the A wing have added refrigerators and microwave ovens close to their workstations.
D. The A wing has had a computer network for three years; the other wings have had a network for four years.
E. Hosts in the A wing are located next to the manufacturing shop.
F. The A wing has Cat 5 cable throughout, while the other wings have wireless and Cat 5.
A, C, E. A: The A wing, having the most connected workers, can have too much traffic on the cable and packets can be getting dropped. C: Refrigerator compressors and microwave ovens can cause interference on a network. E: Because orders are up, the wing’s proximity to the manufacturing shed could be because of electromagnetic interference from the machines on the production line.
Incorrect answers: B: The janitor’s actions are intermittent, and the network problems are consistent. D and F: These differences should provide more reliability, not less.
163. Name the two data link sublayers, and list their purposes
The two data link sublayers are as follows:
■ Logical Link Control (LLC): Handles the communication between the upper layers and the lower layers, typically hardware.
■ MAC: The Ethernet MAC sublayer has the following responsibilities:
■ Data encapsulation
■ Media access control
■ Addressing
164. Which of the following describes a limitation of legacy Ethernet technologies?
A. Poor scalability
B. Expensive media
C. No collisions
D. Frame format incompatible with current Ethernet
A. Poor scalability
165. Which field of an Ethernet frame is used for error detection?
A. Type
B. Preamble
C. Frame Check Sequence
D. Destination MAC Address C. Frame Check Sequence. The FCS (4 bytes in length) field is used to detect errors in a frame.
166. How many bits are in an Ethernet MAC address?
A. 12
B. 32
C. 48
D. 256
C. An Ethernet MAC address is a 48-bit binary value expressed as 12 hexadecimal digits.
167. Why are Layer 2 MAC addresses necessary?
An Ethernet MAC address is used to transport the frame across the local media.
168. Which of the following addresses is used as a destination address for an Ethernet broadcast frame?
A. 0.0.0.0
B. 255.255.255.255
C. FF-FF-FF-FF-FF-FF
D. 0C-FA-94-24-EF-00
C. The Ethernet broadcast MAC address is FF-FF-FF-FF-FF-FF. Frames with this destination address are delivered to and processed by all the devices on that LAN segment.
169. What is the purpose of the jam signal in CSMA/CD?
A. To allow the media to recover
B. To make sure that all sending nodes see the collision
C. To notify other nodes that a node is about to send
D. To identify the length of a frame B. The jam signal in CSMA/CD makes sure that all sending nodes see the collision.
170. Describe an Ethernet collision domain
The group of connected devices that can cause collisions to occur with each other is known as a collision domain. Collision domains occur at Layer 1 of the networking reference model.
171. What Ethernet characteristic is shared by historic Ethernet and legacy Ethernet?
A. Same cable type
B. Same segment lengths
C. Same logical topology
D. Same installation cost C. Historic Ethernet and legacy Ethernet both use logical bus topology.
172. Which of the following describes a connection to a switch port?
A. Isolates broadcasts
B. Is a separate collision domain
C. Uses the MAC address of the switch port as the destination
D. Regenerates every bit that arrives out every port on the switch
B. Is a separate collision domain
173. What is the stage of operation of an Ethernet switch that creates MAC table entries?
A. Aging
B. Filtering
C. Flooding
D. Learning
D. Learning. When a frame of data is received from a node, the switch reads the source MAC address and saves the address to the lookup table against the incoming interface. The switch now knows out which interface to forward frames with this address.
174. If a frame arrives at a switch that contains a source MAC address that is not listed in the MAC table, what process will occur?
A. Aging
B. Filtering
C. Flooding
D. Learning
D. Learning. When a frame of data is received from a node, the switch reads the source MAC address and saves the address to the lookup table against the incoming interface. The switch now knows out which interface to forward frames with this address.
175. When does a network host need to broadcast an ARP request?
When a host has a packet to send to an IP address that does not have a map in the ARP cache.
176. If a frame arrives at a switch that contains a destination MAC address that is not listed in the MAC table, what process will occur?
A. Aging
B. Filtering
C. Flooding
D. Learning
C. Flooding. When the switch does not have a destination MAC address in its lookup table, it sends (floods) the frame out all interfaces except the one on which the frame arrived.
177. Why are higher-speed Ethernet implementations more susceptible to noise?
A. More collisions
B. Shorter bit times
C. Full-duplex operation
D. UTP cables are required instead of fiber
B. Timing can be more easily distorted with the shorter bit times.
178. (Discuss why Ethernet has maintained the same frame format and what might have resulted from changing the frame format.
Can vary.) With the same frame format, different implementations of Ethernet (PHY) maintain compatibility. Changing the frame format would have resulted in different “Ethernets” that were not compatible.
179. (Discuss the reasons why using LAN switches improves the security of a network.
Can vary.) The primary reason is that the frames are not sent to every device. If a device receives a frame, it can be examined to obtain the sensitive information.

180 .Which function is a unique responsibility of the DCE devices shown in Figure 10-25?
A. Transmission of data
B. Reception of data
C. Clocking for the synchronous link
D. Noise cancellation in transmitted data
C. One of the primary responsibilities of a DCE device is to provide clocking to the routers for synchronization.
181. You have been given the 178.5.0.0/16 network and are assigned to create as many possible subnets with at least 100 hosts. What subnet mask will you use?
A. 255.255.255.128
B. 255.255.255.192
C. 255.255.255.0
D. 255.255.254.0
A. To have at least 100 hosts, your networks must go up by 128. So, you would have to subnet 178.5.0.0/16 to 178.5.0.0/25. This would make your first network 178.5.0.0, your second network 178.5.0.128, your third network 178.5.1.0, your fourth network 178.5.1.128, your fifth network 178.5.2.0, and so on.
182. What would be the most efficient subnet mask to use if you needed as many subnets as possible with 32 hosts each?
A. 255.255.255.240
B. 255.255.255.0
C. 255.255.255.224
D. 255.255.255.192
D. If you increment your network by 32, you lose two (the network and broadcast address), so you must jump up to 64, which equals 128 + 64 = 192.
183. What is the valid host range for the subnet 154.65.128.0 255.255.248.0?
A. 154.65.128.1–154.65.128.255
B. 154.65.128.1–154.65.135.254
C. 154.65.120.1–154.65.135.255
D. 154.65.0.0–154.65.255.254
B. A 248 means that you are incrementing your network in steps of 8 (128 + 64 = 192 + 32 = 224 + 16 = 240 + 8 = 248). If you increment in steps of 8, your networks would be 154.65.128.0 to 154.65.136.0, the next network. That would mean 154.65.128.0 would be the network address, 154.65.128.1 to 154.65.128.254 would be the hosts, and 154.65.128.255 would be the broadcast address.
184. 100BASE-FX uses fiber cabling and supports full duplex up to a distance of ________ meters?
A. 100
B. 1000
C. 200
D. 2000
D. 100BASE-FX uses fiber cabling and supports full duplex up to a distance of 2000 meters.
185. True or false: A T568A cabling code states that pin 1 and pin 2 would be a green pair of wires.
True.
186. List where a straight-through UTP cable would be used in connecting network devices.
A straight-through UTP cable would be used to connect these devices:
■ Switch to router
■ PC to switch
■ PC to hub (if used)
187.A crossover UTP cable would be used to connect these devices:
■ Switch to switch
■ Switch to hub (if used)
■ Hub to hub (if used)
■ PC to PC
■ PC to router
188.Describe the purposes of and differences between DCE and DTE WAN serial cables and devices
The terms DCE and DTE are described as follows:
■ Data communication equipment (DCE): A device that supplies the clocking to another device. It is typically a device at the WAN access provider end of the link.
■ Data terminal equipment (DTE): A device that receives clocking from another device and adjusts accordingly. Typically this device is at the WAN customer or user end of the link.
In a lab environment, generally connect two routers with a serial cable, providing a point-to-point WAN link. In this case, decide which router is going to be the one in control of the clocking. Cisco routers are DTE devices by default but can be configured to act as DCE devices.
189. List criteria that should be considered when selecting a switch for a LAN.
The following criteria should be considered:
■ Cost
■ Cable/wireless
■ Speed
■ Ports
■ Expandability
■ Manageability
■ Features
190. Give examples of the different types of hosts and network devices that require IP addresses.
End devices requiring IP addresses include
■ User computers
■ Servers
■ Other end devices such as printers, IP phones, and IP cameras
Network devices requiring IP addresses include
■ Router LAN gateway interfaces
■ Router WAN (serial) interfaces
200. List three reasons for subnetting a network.
Reasons for subnetting a network include
■ Manage broadcast traffic
■ Similar network requirements
■ Security
201. List the five factors to consider when selecting the type of physical media to deploy in the LAN.
The five factors to consider are as follows:
■ Cable length
■ Cost
■ Bandwidth
■ Ease of installation
■ Susceptibility to EMI/RFI

202. Which addresses are valid host IP addresses, given the subnet mask 255.255.255.248? (Choose three.)
A. 192.168.200.87
B. 194.10.10.104
C. 223.168.210.100
D. 220.100.100.154
E. 200.152.2.160
F. 196.123.142.190
C, D, F. A 255.255.255.248 mask would mean that the networks would increment in steps of 8. In other words, the network addresses would be 0, 8, 16, 24, 32, 40, 48, 56, 64, 72, 80, 88, 96, 104, 112, 120, 128, 136, 144, 152, 160, 168, 176, 184, 192, 200, 208, 216, 224, 232, 240, and 248. Hence:
A. would not be correct. 192.168.200.87 would be the broadcast address for the network 192.168.200.80.
B. would not be correct. 194.10.10.104 would be a network address.
C. 223.168.210.100 is correct, a host on the 223.168.210.96 network.
D. 220.100.100.154 is correct, a host on the 220.100.100.152 network.
E. 200.152.2.160 is not correct. It is a network address.
F. 196.123.142.190 is correct, a host on the 196.123.142.184 network.
203. Host A in Figure 10-26 is assigned the IP address 10.118.197.55/20. How many more network devices can be added to this same subnetwork?
A. 253
B. 509
C. 1021
D. 2045
E. 4093
E. A /20 would yield 4096 possible IP addresses, minus 1 for the network address, minus 1 for the broadcast address, and minus 1 for the host address already used. That would provide you with 4093 IP addresses left for network devices.
204. The devices in Figure 10-27 have been configured with a static IP address from the network 192.168.102.0. All hosts can communicate with each other but cannot communicate with the server. What is causing this problem?

A. The IP address assigned to the server is outside the subnet.
B. The IP address assigned to the server is a broadcast address.
C. The IP address assigned to the server is a network address.
D. The switch that the server is connected to has not been assigned an IP address.
E. The route connected to the 192.168.102.96 network is configured for the 192.168.102.64 network.

A. Using the fact that a /27 would increment the networks by 32, you have the following networks, per Figure 10-27: 192.168.102.0, 192.168.102.32, 192.168.102.64, 192.168.102.96, 192.168.102.128, 192.168.102.160, 192.168.102.192, and 192.168.102.224. Option A is correct because the server address of 192.168.102.147 falls out of the 192.168.102.96 network.
205. A contractor is installing cable for a new hospital network. The cable specifications require that the network be protected from EMI and have a supported bandwidth of 1000 Mbps. Which cable type would meet both specifications?
A. Thinnet coaxial cable
B. Thicknet coaxial cable
C. Category 5 UTP cable
D. Category 5 STP cable
E. Fiber-optic cable
E. The only option is to use fiber-optic cable. Thinnet and Thicknet would provide EMI protection but could not provide the bandwidth.
206. Which two items are required for initial configuration of Cisco routers?
A. Crossover cable
B. Rollover cable
C. RJ-15–to–DB-9 adapter
D. Terminal emulation software
E. Router VTY port
B, D. Initial configuration of a Cisco router must be accomplished through the console port, and that requires a rollover cable and terminal emulation software.
207. List four types of interfaces found on Cisco routers and switches, and give the function of eachThe four types of interfaces are as follows:
■ Ethernet: This interface is used for connection of the LAN device, which includes computers and switches. This interface can also be used to connect routers.
■ Serial: This interface is used for connection of the WAN devices to the CSU/DSU. Clock rate and addressing are assigned to these interfaces.
■ Console: This is the primary interface for gaining initial access to and configuration of a Cisco router or switch and is the primary means of troubleshooting. It is important to note that through physical access to the console interface router, an unauthorized person can interrupt or compromise network traffic. Physical security is extremely important.
■ Auxiliary (AUX): This interface is used for remote, out-of-band management of the router. Typically a modem is connected to the AUX interface for dialup access. From a security standpoint, having the ability to remotely dial in to a network device also requires vigilant management.

208. Which command turns on a router interface?
A. Router(config-if)#enable
B. Router(config-if)#no down
C. Router(config-if)#s0 active
D. Router(config-if)#interface up
E. Router(config-if)#no shutdown
E. The no shutdown command, given at the interface prompt, will bring the interface up. The enable command moves you from operating at the user mode to the privileged mode. S0 active and interface up are not legal IOS commands.
209. What is the purpose of the IOS enable secret command?
A. To set password protection on incoming Telnet sessions
B. To set password protection on the console terminal
C. To allow a user access to user mode
D. To allow a user to enter a password that will be encrypted.
D. The enable secret command allows you to input a password that will be used to get you from the user to the privilege mode. This password will be encrypted.
210. Which command will display statistics for all interfaces configured on a router?
A. list interfaces
B. show interfaces
C. show processes D. show statistics
B. The show interfaces command will display statistics for all interfaces configured on a router. It is the only legal command listed.
211. What command will display a list of commands available for viewing the status of the router?
A. Router #?show
B. Router# sh?
C. Router# show?
D. Router# help
E. Router# status?
C. The show command will provide you with numerous commands that can be used for viewing router status. The ? will list those commands.
212. An administrator configures a new router and names it SanJose. The administrator needs to set a password that will be required to establish a console session with the router. What command should be issued by the administrator to set the console password to CISCO?
A. SanJose(config)#enable password CISCO
B. SanJose(config)#line con 0
SanJose(config-line)#login
SanJose(config-line)#enable password CISCO
C. SanJose(config)#enable console password CISCO
D. SanJose(config)#line con 0
SanJose(config-line)#login
SanJose(config-line)#password CISCO
D. The administrator should issue the following commands, which are presented in the correct sequence, and the proper format:
SanJose(config)#line con 0
SanJose(config-line)#login
SanJose(config-line)#password CISCO
213. What type of cable is used to initially configure a router?
A rollover cable connected to the serial port of a computer is used.
214. The console port can be used for which of the following? (Choose three.)
A. Debugging
B. Password recovery
C. Routing data between networks
D. Troubleshooting
E. Connecting one router to another
A, B, D. The console port is used strictly to access the configuration of the router; it cannot be used for data routing or for connecting one router to another.
215. What do routers use to select best paths for outgoing data packets?
A. ARP tables
B. Bridging tables
C. Routing tables
D. Switching tables
C. Routers store routing tables that basically match network addresses to the best exit interface.
216. What is setup mode? Setup mode allows you to configure a router by answering a series of questions posed to you.

Terminal emulation software, such as HyperTerminal, can be used to configure a router. Which of the following HyperTerminal options, shown in Figure 11-16, are correctly set to allow configuration of a Cisco router. (Choose three.)
A. Bits per second
B. Data bits
C. Parity
D. Stop bits
E. Flow control

B, C, D. Bits per second would have to be set to 9600 to be correct, and Flow control would have to be set to None to be correct.
217. A router is composed of many internal components. Where are the main configuration files of the router stored?
The router stores the running-configuration file in RAM. The router stores the start-up configuration file, the file created when you save the running-configuration file, in NVRAM.
218. Select the statement that correctly describes flash memory in a router.
A. Holds the startup configuration by default
B. Stores Cisco IOS Software images
C. Stores routing table information by default
D. Maintains the only copy of an IOS image after the router is booted B. The IOS is stored in flash and then run and/or uncompressed in RAM. All other choices are stored either in RAM or NVRAM.