Chapter1 Flashcards
Which of the following pairs of well-known ports are the default values you would use to configure a POP3 email client? 110 and 25 143 and 25 110 and 143 80 and 110 25 and 80
A. The default port for the Post Office Protocol (POP3) is 110. The default port for the Simple Mail Transfer Protocol (SMTP), the other protocol used by email clients, is 25. Port 143 is the default for the Internet Message Access Protocol (IMAP), a different email mailbox protocol that clients never use with POP3. Port 80 is the default for the Hypertext Transfer Protocol (HTTP), which is not used by email clients.
Which of the following server applications use two well-known port numbers during a typical transaction? NTP SNMP HTTP FTP
D. The File Transfer Protocol (FTP) uses two port numbers. It uses the first, port 21, for a control connection that remains open during the entire client/server session. The second port, 20, is for a data connection that opens only when the protocol is actually transferring a file between the client and the server. Network Time Protocol (NTP), Simple Network Management Protocol (SNMP), and Hypertext Transfer Protocol (HTTP) all use a single port on the server.
Which of the following protocols does the Ping utility use to exchange messages with another system? UDP TCP ICMP IGMP
. Ping uses the Internet Control Message Protocol (ICMP) to exchange messages with other systems. ICMP is also used to return error messages to sending systems. The User Datagram Protocol (UDP) and the Transmission Control Protocol (TCP) are both transport layer protocols that carry application layer data; Ping does not use either one. The Internet Group Management Protocol (IGMP) is used to create multicast groups; Ping does not use it.
Which of the following components does the port number in a transport layer protocol header identify? A transport layer protocol An application A gateway A proxy server
B. The port numbers specified in a transport layer protocol header identify the application that generated the data in the packet or the application that will receive the data. Port numbers do not identify transport layer protocols, gateways, or proxy servers.
Which of the following organizations is responsible for assigning the well-known port numbers used in transport layer protocol headers?
Institute for Electronic and Electrical Engineers (IEEE)
Internet Assigned Numbers Authority (IANA)
Internet Engineering Task Force (IETF)
International Organization for Standardization (ISO)
B. The IANA assigns values for well-known port numbers. The IEEE publishes Ethernet standards, among many others. The IETF develops standards for Internet technologies. The ISO developed the Open Systems Interconnection (OSI) model.
A client on a TCP/IP network is attempting to establish a session with a server. Which of the following correctly lists the order of Transmission Control Protocol (TCP) session establishment messages? SYN, ACK, SYN, ACK SYN, SYN, ACK, ACK SYN/ACK, SYN/ACK SYN, SYN/ACK, ACK
D. The TCP connection establishment exchange is a three-way handshake. The first frame contains a SYN message from the client, the second frame contains a SYN/ACK message from the server, and the last frame contains an ACK message from the client.
Which of the following is the default well-known port number for the Hypertext Transfer Protocol (HTTP) used for web client/server communications? 22 20 80 1720
C. Port 80 is the default well-known port for HTTP. Port 22 is for the Secure Shell (SSH) protocol, port 20 is for File Transfer Protocol (FTP), and 1720 is for the H.323 audio/video-conferencing protocol.
The secured version of the Hypertext Transfer Protocol (HTTPS) uses a different well-known port from the unsecured version. Which of the following ports is used by HTTPS by default? 25 80 110 443
D. The well-known port for HTTPS is 443. Port 25 is for the Simple Mail Transfer Protocol (SMTP), port 80 is for unsecured HTTP, and port 110 is for the Post Office Protocol (POP3).
Which of the following Transmission Control Protocol (TCP) control bits is set to 1 to initiate the termination of a session? SYN URG FIN END PSH
C. The termination phase of a TCP connection begins when either the client or the server sends a message containing the FIN control bit with a value of 1. The other control bits listed have nothing to do with the connection termination procedure, and there is no END bit.
What field in the Transmission Control Protocol (TCP) Option subheader specifies the size of the largest segment a system can receive? MSS Window MMS WinMS
A. The Maximum Segment Size (MSS) field in the TCP Options subheader specifies the size (in bytes) of the largest segment a system can receive. The Window field indicates the amount of data (in bytes) that the receiver can accept. There are no MMS or WinMS fields in a TCP header.
What is the term for the combination of an IPv4 address and a port number, as in the following example: 192.168.1.3:23? Socket OUI Well-known port Network address Domain
A. The term for an IPv4 address and port number in combination is socket. An organizationally unique identifier (OUI) identifies a manufacturer of networking hardware. A well-known port is a port number assigned to a specific application. A network address is the network identifier part of an IP address. A domain is a group of computers and other resources.
Which of the following protocols generate messages that are carried directly within Internet Protocol (IP) datagrams, with no intervening transport layer protocol? (Choose all correct answers.) ICMP IGMP SMTP SNMP
A and B. Internet Control Message Protocol (ICMP) and Internet Group Management Protocol (IGMP) are unusual in that they generate messages that are encapsulated directly within IP datagrams. Nearly all of the other TCP/IP protocols, including Simple Mail Transfer Protocol (SMTP) and Simple Network Management Protocol (SNMP), are encapsulated within one of the transport layer protocols—User Datagram Protocol (UDP) or Transmission Control Protocol (TCP)—which is encapsulated in turn within an IP datagram.
Which of the following protocols is used to exchange directory service information? RDP LDAP SNMP SMB
B. The Lightweight Directory Access Protocol (LDAP) is an application layer protocol used for managing and accessing information stored in directory services. Remote Desktop Protocol (RDP) is used to establish a graphical remote control session with another computer. Simple Network Management Protocol (SNMP) is used to carry information gathered by management agents distributed around a network to a central management server. Server Message Block (SMB) is the primary file sharing protocol used by Windows systems.
Which of the following is the primary application layer protocol used by web browsers to communicate with web servers? HTTP HTML SMTP FTP
A. The Hypertext Transfer Protocol (HTTP) is the primary protocol used for web client/server communications. Hypertext Markup Language is a coding language used to create web content. Simple Mail Transfer Protocol (SMTP) and File Transfer Protocol (FTP) can both be used in web communications, but neither is the primary protocol.
Which of the following protocols appears on the network as a service that client computers use to resolve names into IP addresses? DHCP BOOTP DNS SNMP
C. The Domain Name System (DNS) is a protocol that computers on a TCP/IP network use to resolve host and domain names into the IP addresses they need to communicate. Dynamic Host Configuration Protocol (DHCP) and Bootstrap Protocol (BOOTP) are both IP address allocation protocols, and Simple Network Management Protocol (SNMP) carries information gathered by agents to a central management console.
Which of the following protocols use(s) the term datagram to describe the data transfer unit it creates? (Choose all correct answers.) Ethernet IP TCP UDP
B and D. The term datagram is typically used by protocols offering connectionless delivery service. The two main connectionless protocols in the TCP/IP suite are the Internet Protocol (IP) and the User Datagram Protocol (UDP), both of which use the term datagram. Ethernet uses the term frame, and Transmission Control Protocol (TCP) uses segment.
What is the native file sharing protocol used on all Microsoft Windows operating systems?
Hypertext Transfer Protocol (HTTP)
Network File System (NFS)
File Transfer Protocol (FTP)
Server Message Block (SMB)
Lightweight Directory Access Protocol (LDAP)
D. The default file sharing protocol used on all Windows operating systems is SMB. HTTP is the native protocol used by web clients and servers. NFS is the native file sharing protocol used on Unix/Linux networks. FTP is a protocol used for transferring files from one system to another. LDAP is a protocol for transmitting directory service information.
When analyzing captured TCP/IP packets, which of the following control bits must you look for in the Transmission Control Protocol (TCP) header to determine whether the receiving host has successfully received the sending host’s data? ACK FIN PSH SYN URG
A. The receiving host uses the ACK bit to notify the sending host that it has successfully received data. The other control bits are not used to acknowledge receipt of information.
Which of the following terms describes the Transmission Control Protocol (TCP) exchange that establishes a connection prior to the transmission of any data? Synchronization Initialization exchange Connection establishment Three-way handshake
D. Two systems establishing a TCP connection exchange three messages before they begin transmitting data. The exchange of these synchronization messages is referred to as a three-way handshake. The other terms listed are not formally used to describe this exchange.
Alice has been instructed to install 100 Windows workstations, and she is working on automating the process by configuring the workstations to use PXE boots. Each workstation therefore must obtain an IP address from a DHCP server and download a boot image file from a TFTP server. Which of the following well-known ports must Alice open on the firewall separating the workstations from the servers? (Choose all correct answers.) 65 66 67 68 69
C, D, and E. Dynamic Host Configuration Protocol (DHCP) servers use port numbers 67 and 68. The Trivial File Transfer Protocol (TFTP) uses port number 69. Neither protocol uses port 65 or 66.
Which of the following explanations best describes the function of a Transmission Control Protocol (TCP) or User Datagram Protocol (UDP) port number?
The port number indicates to the receiver that the sender can activate a specific port only.
The port number is used by both the sender and the receiver to identify the application that generated the information in the datagram.
The port number is used only by the receiver to indicate the application process running on the sender.
The port number is used by both the sender and the receiver to negotiate a well-known server port for the communicating processes.
B. TCP ports and UDP ports identify the application protocol or process that generated the information in a datagram. Client ports are chosen randomly from the range 1024 through 65,534. Server ports are well-known and are chosen from the range 1 through 1023.
What is the valid range of numbers for the ephemeral client ports used by the Transmission Control Protocol (TCP) and User Datagram Protocol (UDP)? 1023 through 65534 1 through 1024 49152 through 65535 1024 to 49151
C. Ephemeral client ports fall in the range of 49152 through 65535. Well-known TCP and UDP server ports fall in the range of 1 through 1023. Registered port numbers fall in the range from 1024 to 49151.
Which of the following statements about the User Datagram Protocol (UDP) are true? (Choose all correct answers.)
UDP does not use packet sequencing and acknowledgments.
UDP uses packet sequencing and acknowledgments.
UDP is a connection-oriented protocol.
UDP is a connectionless protocol.
UDP has an 8-byte header.
UDP has a 20-byte header.
A, D, and E. UDP is a connectionless transport layer protocol. It has a small, 8-byte header and does not use packet sequencing or acknowledgments.
Which of the following port values are used by the File Transfer Protocol (FTP)? (Choose all correct answers.) 21 23 20 53 69
A and C. FTP uses two ports: one for control messages (port 21) and one for data transfers (port 20). Port 23 is used by Telnet. Port 53 is used by the Domain Name System (DNS). Port 69 is used by the Trivial File Transfer Protocol (TFTP).
Which of the following protocols provides connectionless delivery service at the transport layer of the Open Systems Interconnection (OSI) model? TCP HTTP UDP ARP
C. The User Datagram Protocol (UDP) provides connectionless service at the transport layer. TCP provides connection-oriented service at the transport layer. HTTP is an application layer protocol, and ARP is a data link layer protocol
What is the valid range of numbers for the well-known Transmission Control Protocol (TCP) and User Datagram Protocol (UDP) ports used by servers? 1024 through 49151 1 through 49151 49152 through 65534 1 through 1023
D. Well-known TCP and UDP server ports fall in the range of 1 through 1023. Registered port numbers fall in the range from 1024 to 49151. Ephemeral client ports fall in the range of 49152 through 65535.
Ralph is a network administrator who has just installed a new open source email server for the users at his company. The server is configured to send and receive Internet email and create a mailbox for each user that will permanently store the user’s mail on the server. Ralph next uses a protocol analyzer to examine the network traffic resulting from the new server installation. Which of the following new protocols should Ralph expect to see in his network traffic analysis? (Choose all correct answers.) SNMP SMTP POP3 IMAP RIP
B and D. Ralph’s traffic analysis should show the addition of the Simple Mail Transfer Protocol (SMTP), which handles incoming and outgoing Internet mail, and Internet Message Access Protocol (IMAP), which provides mailboxes for users who store their mail permanently on the server. POP3 is a mailbox protocol that enables users to download their messages and should therefore not be present on the network. SNMP is a network management protocol and RIP is a routing protocol; neither of them carries email traffic.
Which of the following values could a web client use as an ephemeral port number when communicating with a web server? 1 23 80 1024 1999 50134
F. An ephemeral port number is a temporary port supplied by a client to a server, for use during a single session or transaction. The allowed ephemeral port number values range from 49152 to 65535. The port values below 1024 are reserved for use as well-known ports, and the values from 1024 to 49151 are reserved for ports registered by specific manufacturers for their applications. Of these answers, 50134 is the only value that the client can use as an ephemeral port.
Which of the following protocols provides connection-oriented service with guaranteed delivery at the transport layer of the OSI model? TCP HTTP UDP IP
A. The Transmission Control Protocol (TCP) provides connection-oriented service at the transport layer, with guaranteed delivery. The User Datagram Protocol (UDP) provides connectionless service at the transport layer. Hypertext Transfer Protocol (HTTP) operates at the application layer, and Internet Protocol (IP) is a connectionless network layer protocol.
Which of the following protocols is limited to use on the local subnet only?
Address Resolution Protocol (ARP)
Dynamic Host Configuration Protocol (DHCP)
Domain Name System (DNS)
Simple Mail Transfer Protocol (SMTP)
A. ARP relies on broadcast transmissions, which are not routable. It is therefore limited to use on the local subnet. DHCP also relies on broadcasts, but the ability to create DHCP relay agents makes it usable on an entire internetwork. DNS and SMTP do not rely on broadcasts and are therefore not limited to the local subnet.
At which of the following layers of the Open Systems Interconnection (OSI) model do the protocols on a typical local area network use MAC addresses to identify other computers on the network? Physical Data link Network Transport
B. The Ethernet (or IEEE 802.3) protocol at the data link layer uses MAC addresses to identify computers on the local network. Media access control (MAC) addresses are coded into the firmware of physical network interface adapters by the manufacturer. The physical layer deals with signals and is not involved in addressing. The IP protocol at the network layer has its own addressing system. The transport layer protocols are not involved in addressing
Which of the following organizations developed the Open Systems Interconnection (OSI) model?
International Telecommunication Union (ITU-T)
Comité Consultatif International Télégraphique et Téléphonique (CCITT)
American National Standards Institute (ANSI)
Institute of Electrical and Electronics Engineers (IEEE)
International Organization for Standardization (ISO)
E. ISO developed and published the OSI model to serve as a conceptual model for software and hardware developers. The ITU-T, formerly known as the CCITT, coordinates the development and advancement of international telecommunication networks and services. ANSI is a private organization that administers and coordinates a United States–based standardization and conformity assessment system. The IEEE publishes standards that define data link and physical layer standards. These standards are referred to collectively as the 802 series.
Which layer of the Open Systems Interconnection (OSI) model is responsible for the logical addressing of end systems and the routing of datagrams on a network? Physical Data link Network Transport Session Presentation Application
C. Network layer protocols specify logical addresses for end system communication and route datagrams across a network. The physical layer defines standards for physical and mechanical characteristics of a network. The data link layer uses media access control (MAC) or hardware addresses, not logical addresses. The transport layer uses port numbers, not logical addresses. Session layer protocols create and maintain a dialogue between end systems. Presentation layer protocols are responsible for the formatting, translation, and presentation of information. The application layer provides an entry point for applications to access the protocol stack and prepare information for transmission across a network.
What layer of the Open Systems Interconnection (OSI) model is responsible for translating and formatting information? Physical Data link Network Transport Session Presentation Application
F. The presentation layer implements functions providing formatting, translation, and presentation of information. No other layers of the OSI model translate and format application data.
Which of the following devices typically operates at the network layer of the Open Systems Interconnection (OSI) model? Proxy server Hub Network interface adapter Router
D. A router connects networks together at the network layer of the OSI model. Proxy servers operate at the application layer. Network interface adapters operate at both the data link and the physical layers. Hubs are physical layer devices.
Which layer of the Open Systems Interconnection (OSI) model provides an entrance point to the protocol stack for applications? Physical Data link Network Transport Session Presentation Application
G. The application layer provides an entry point for applications to access the protocol stack and prepare information for transmission across a network. All other layers of the OSI model reside below this layer and rely on this entry point.
Which layer of the Open Systems Interconnection (OSI) model is responsible for dialogue control between two communicating end systems? Physical Data link Network Transport Session Presentation Application
E. The session layer is responsible for creating and maintaining a dialogue between end systems. This dialogue can be a two-way alternate dialogue that requires end systems to take turns transmitting, or it can be a two-way simultaneous dialogue in which either end system can transmit at will. No other layers of the OSI model perform dialogue control between communicating end systems.
Some switches can perform functions associated with two layers of the Open Systems Interconnection (OSI) model. Which two of the following layers are often associated with network switching? (Choose all correct answers.) Physical Data link Network Transport Session Presentation Application
B and C. The primary function of a switch is to process packets based on their media access control (MAC) addresses, which makes it a data link layer device. However, many switches can also perform routing functions based on IP addresses, which operate at the network layer.
At which layer of the Open Systems Interconnection (OSI) model are there TCP/IP protocols that can provide either connectionless or connection-oriented services to applications? Physical Data link Network Transport Session Presentation Application
D. There are two types of transport layer protocols: connection-oriented and connectionless. Connection-oriented protocols guarantee the delivery of data from source to destination by creating a connection between the sender and the receiver before any data is transmitted. Connectionless protocols do not require a connection between end systems in order to pass data. The physical layer does not use connectionless or connection-oriented protocols; it defines standards for transmitting and receiving information over a network. The data link layer provides physical addressing and final packaging of data for transmission. The network layer is responsible for logical addressing and routing. The session layer is responsible for creating and maintaining a dialogue between end systems. The presentation layer is responsible for the formatting, translation, and presentation of information. The application layer provides an entry point for applications to access the protocol stack and prepare information for transmission across a network.
Which of the following layers of the Open Systems Interconnection (OSI) model typically have dedicated physical hardware devices associated with them? (Choose all correct answers.) Physical Data link Network Transport Session Presentation Application
A, B, and C. The physical layer of the OSI model is associated with hubs, cables, and network interface adapters. The data link layer is associated with bridges and switches. The network layer is associated with routers. The transport, session, presentation, and application layers are typically not associated with dedicated hardware devices.
At which layer of the Open Systems Interconnection (OSI) model is there a protocol that adds both a header and footer to the information that is passed down from an upper layer, thus creating a frame? Physical Data link Network Transport Session Presentation Application
B. The only layer with a protocol (such as Ethernet) that adds both a header and a footer is the data link layer. The process of adding the headers and footers is known as data encapsulation. All other protocol layers that encapsulate data add just a header.
Identify the layer of the Open Systems Interconnection (OSI) model that controls the addressing, transmission, and reception of Ethernet frames, and also identify the media access control method that Ethernet uses.
Physical layer; Carrier Sense Multiple Access with Collision Detection (CSMA/CD)
Physical layer; Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA)
Data link layer; CSMA/CD
Data link layer; CSMA/CA
C. The Ethernet protocol that handles the addressing, transmission, and reception of frames operates at the data link layer. Each frame includes hardware addresses that identify the sending and receiving systems on the local network. Ethernet uses the CSMA/CD media access control method. Physical layer specifications include the transmission of signals in the form of electrical or light pulses to represent binary code, not frames. CSMA/CA is a data link layer media access control method used by wireless LAN protocols, but not Ethernet.
At which layer of the OSI model do you find the protocol responsible for the delivery of data to its ultimate destination on an internetwork? Data link Network Session Application
B. On a TCP/IP network, the Internet Protocol (IP) at the network layer is the protocol responsible for the delivery of data to its final destination. Data link layer protocols are only concerned with communication between devices on a local area network (LAN) or between two points connected by a wide area network (WAN). The session and application layers are not involved in the actual delivery of data.
Which of the following is not a protocol operating at the network layer of the OSI model? IP ICMP IGMP IMAP
D. Internet Protocol (IP), Internet Control Message Protocol (ICMP), and Internet Group Message Protocol (IGMP) are all network layer protocols. Internet Message Access Protocol (IMAP) is a mail protocol that operates at the application layer.
Ed is a software developer who has been given the task of creating an application that requires guaranteed delivery of information between end systems. At which layer of the Open Systems Interconnection (OSI) model does the protocol that provides the guaranteed delivery run, and what type of protocol must Ed use? Data link layer; connectionless Network layer; connection-oriented Transport layer; connection-oriented Application layer; connectionless
C. A connection-oriented transport layer protocol provides guaranteed delivery of data for upper layer applications. Connectionless protocols do not guarantee delivery of information and therefore are not a good choice. Guaranteed delivery of information is generally not a function of the data link, network, or application layer.
Which of the following devices operates only at the physical layer of the Open Systems Interconnection (OSI) model? Hub Bridge Switch Router
A. A hub functions only at the physical layer by forwarding all incoming signals out through all of its ports. Bridges and switches operate at the physical layer and the data link layer by selectively propagating incoming data. Routers operate at the network layer by connecting local area networks and propagating only the traffic intended for another network, based on IP addresses.
Alice is a network administrator designing a new local area network (LAN). She needs to determine the type of cabling and the network topology to implement. Which layers of the Open Systems Interconnection (OSI) model apply to cabling and topology elements? Physical and data link layers Data link and network layers Network and transport layers Transport and application layers
A. The physical layer defines the mechanical and electrical characteristics of the cables used to build a network. The data link layer defines specific network (LAN or WAN) topologies and their characteristics. The physical layer standard that Alice will implement is dependent on the data link layer protocol she selects. The network, transport, and application layers are not concerned with cables and topologies.
Which layers of the Open Systems Interconnection (OSI) model do not have protocols in the TCP/IP suite exclusively dedicated to them? (Choose all correct answers.) Physical Data link Network Transport Session Presentation Application
E and F. In the TCP/IP suite, the functions of the session layer are primarily implemented in the transport layer protocols: Transmission Control Protocol (TCP) and User Datagram Protocol (UDP). The presentation layer functions are often implemented in application layer protocols, although some functions, such as encryption, can also be performed by transport or network layer protocols.
The protocols at which layer of the Open Systems Interconnection (OSI) model use port numbers to identify the applications that are the source and the destination of the data in the packets? Application Presentation Transport Network
C. Transport layer protocols, such as Transmission Control Protocol (TCP) and User Datagram Protocol (UDP), have header fields that contain the port numbers of the applications that generated the data in the packet and that will receive it. The application, presentation, and network layers do not use port numbers.
Which of the following is a correct listing of the Open Systems Interconnection (OSI) model layers, in order, from top to bottom?
Physical, data link, transport, network, session presentation, application
Application, session, presentation, transport, network, data link, physical
Presentation, application, transport, session, network, physical, data link
Session, application, presentation, transport, data link, network, physical
Application, presentation, session, transport, network, data link, physical
E. The correct order of the OSI model layers, from top to bottom, is application, presentation, session, transport, network, data link, physical.
At which of the Open Systems Interconnection (OSI) model layers do switches and bridges perform their basic functions? Physical Data link Network Transport
B. Switches and bridges are involved in local area network (LAN) communications only and therefore operate at the data link layer.
Flow control is a function implemented in protocols operating at which layer of the Open Systems Interconnection (OSI) model? Presentation Session Transport Network
C. Flow control is a process that adjusts the transmission rate of a protocol based on the capability of the receiver. If the receiving system becomes overwhelmed by incoming data, the sender dynamically reduces the transmission rate. In the TCP/IP protocol suite, Transmission Control Protocol (TCP) is responsible for implementing flow control. TCP runs at the transport layer. None of the other layers listed have TCP/IP protocols that provide flow control.
Which layer of the Open Systems Interconnection (OSI) model defines the medium, network interfaces, connecting hardware, and signaling methods used on a network? Physical Data link Network Transport Session Presentation Application
A. The physical layer of the OSI model defines the standards for the physical and mechanical characteristics of a network, such as cabling (copper and fiber), connecting hardware (hubs and switches), and signaling methods (analog and digital). All of the other layers are not involved in the mechanical characteristics of the network.
Which of the OSI model layers is responsible for syntax translation and compression or encryption? Data link Network Session Presentation Application
D. The presentation layer provides a syntax translation service that enables two computers to communicate, despite their use of different bit-encoding methods. This translation service also enables systems using compressed or encrypted data to communicate with each other.
Which layer of the Open Systems Interconnection (OSI) model is responsible for transmitting signals over the network medium? Physical Data link Network Transport Session Presentation Application
A. The physical layer of the OSI model defines the functions specific to the network medium and the transmission and reception of signals. All of the other layers are implemented in software and do not physically send or receive signals.
Specify the layer of the Open Systems Interconnection (OSI) model at which the Internet Protocol (IP) operates and whether it is connection-oriented or connectionless. Network; connection-oriented Network; connectionless Transport; connection-oriented Transport; connectionless
B. IP is a connectionless protocol that operates at the network layer of the OSI model. There are no connection-oriented protocols at this layer. The protocols at the transport layer include Transmission Control Protocol (TCP), which is connection-oriented, and User Datagram Protocol (UDP), which is connectionless.
An Ethernet network interface adapter provides functions that span which two layers of the Open Systems Interconnection (OSI) model? Physical and data link Data link and network Network and transport Transport and application
A. A network interface adapter functions at the data link layer by encapsulating network layer data for transmission over the network. It provides physical layer functions by providing the connection to the network medium and generating the appropriate signals for transmission.
Which of the following protocols operate at the application layer of the Open Systems Interconnection (OSI) model? (Choose all correct answers.) HTTP SNMP ICMP IGMP UDP
A and B. Hypertext Transfer Protocol (HTTP) and Simple Network Management Protocol (SNMP) operate at the application layer. Internet Control Message Protocol (ICMP) and Internet Group Management Protocol (IGMP) both operate at the network layer. User Datagram Protocol (UDP) operates at the transport layer.
Which layer of the Open Systems Interconnection (OSI) model would be responsible for converting a text file encoded using EBCDIC on the sending system into ASCII code, when required by the receiving system? Application Presentation Session Physical
B. The presentation layer of the OSI model is responsible for translating different kinds of syntax, including text-encoding systems, such as EBCDIC and ASCII. The application, session, and physical layers do not perform this function.
Which of the following protocols operates at the network layer of the OSI model but does not encapsulate data generated by an upper layer protocol for transmission over the network? IP UDP ARP ICMP TCP
D. Internet Control Message Protocol (ICMP) operates at the network layer by sending operational and error messages. It does not encapsulate upper layer protocol data. Internet Protocol (IP) operates at the network layer, but it does encapsulate transport layer protocol data. Transmission Control Protocol (TCP) and User Datagram Protocol (UDP) are transport layer protocols that encapsulate upper layer protocol data. Address Resolution Protocol (ARP) does not encapsulate upper layer protocol data, but it is a data link layer protocol.
Which of the following could be a valid MAC address for a network interface adapter? 10.124.25.43 FF:FF:FF:FF:FF:FF 00:1A:6B:31:9A:4E 03:AE:16:3H:5B:11 fe80::89a5:9e4d:a9d0:9ed7
C. A media access control (MAC) address is a six-byte hexadecimal value, with the bytes separated by colons, as in 00:1A:6B:31:9A:4E. Option A, 10.124.25.43, is all decimals and uses periods; this is an IPv4 address. Option B, FF:FF:FF:FF:FF:FF, is a valid MAC address, but this value is reserved for use as a broadcast address. Option D, 03:AE:16:3H:5B:11, is not a valid hexadecimal address, which should contain only numerals and the letters A to F. Option E, fe80::89a5:9e4d:a9d0:9ed7, is too long for a MAC address; this is a valid IPv6 address.
Which of the following TCP/IP parameters, configured on an end system, specifies the Internet Protocol (IP) address of a router on the local network that provides access to other networks? WINS Server Addresses Default Gateway DNS Server Addresses Subnet Gateway
B. The Default Gateway parameter specifies the address of the local router that the end system should use to access other networks. The WINS Server Addresses and DNS Server Addresses parameters are used to resolve names to IP addresses. There is no such parameter as Subnet Gateway.
Which of the following services enables computers on a private IPv4 network to access the Internet using a registered IP address? DHCP NAT DNS NTP
B. Network Address Translation (NAT) is a service that enables computers with unregistered IP addresses to access the Internet by substituting a registered address in packets as they pass through a router. The Dynamic Host Configuration Protocol (DHCP) is an IP address allocation service. Domain Name System (DNS) resolves domain and hostnames into IP addresses, and Network Time Protocol (NTP) enables network devices to synchronize their time settings.
Which of the following protocols prevents network switching loops from occurring by shutting down redundant links until they are needed? RIP STP VLAN NAT
B. The Spanning Tree Protocol (STP) prevents packets from endlessly looping from switch to switch due to redundant links. Creating redundant links is a good preventive against switch failure, but packets transmitted over multiple links can circulate from switch to switch infinitely. STP creates a database of switching links and shuts down the redundant ones until they are needed. Routing Information Protocol (RIP) propagates routing table information. A virtual local area network (VLAN) is an organizational tool that operates within switches by creating multiple broadcast domains. Network Address Translation (NAT) is a routing method that enables private networks to share registered IP addresses.
Which of the following are techniques used in traffic shaping to prevent networks from being overwhelmed by data transmissions? (Choose all correct answers.) Bandwidth throttling Rate limiting Broadcast storming Network address translation
A and B. Bandwidth throttling is a traffic shaping technique that prevents specified data streams from transmitting too many packets. Rate limiting is a traffic shaping technique that controls the transmission rate of sending systems. A broadcast storm is a type of network switching loop. Network address translation is a method by which private networks can share registered IP addresses. Neither of these last two is a traffic shaping technique.
Which of the following best defines the concept of the dual stack?
A computer with two network interface adapters
A computer with two installed operating systems
A computer with two sets of networking protocols
A computer with connections to two different network segments
C. A dual stack is an IP implementation that includes both IPv4 and IPv6 protocol stacks, operating simultaneously. A computer with two network adapters or connections to two network segments is often called multihomed. A computer with two installed operating systems is called a dual-boot system.
An enterprise network has been designed with individual departmental switches because in most cases, the devices in a specific department exchange network traffic with other devices in the same department. Each of the departmental switches is also connected to a host switch, which enables devices to communicate with other departments. Which of the following terms describes this switching architecture? Distributed switching Port forwarding Traffic shaping Neighbor discovery
A. Distributed switching describes a hierarchical switching architecture in which remote switches (in this case departmental switches) handle most of the network traffic, with a host switch used only for traffic between the remote locations. Port forwarding is a routing method that redirects traffic intended for one IP address and port number to another. Traffic shaping is a series of techniques that optimize the allocation of network bandwidth. Neighbor discovery is an IPv6 technique used to find addresses of devices and services on the local network.
Which of the following terms refers to methods by which network traffic is prioritized to prevent applications from suffering faults due to network congestion? Port forwarding Dynamic routing VLANs QoS
D. Quality of service (QoS) is a general term that refers to various mechanisms for prioritizing network traffic so that applications or data streams requiring a certain level of performance are not negatively affected by lower-priority transmissions. Port forwarding is a routing method that redirects traffic intended for one IP address and port number to another. Dynamic routing is a method by which routing tables are automatically updated with new information as the routing fabric of an internetwork changes. Virtual local area networks (VLANs) are a means for partitioning a broadcast domain into discrete units that are functionally equivalent to physical LANs.
Which of the following statements about Routing Information Protocol version 1 (RIPv1) is true? (Choose all correct answers.)
RIPv1 broadcasts the entire contents of the routing table every 30 seconds.
RIPv1 advertises the subnet mask along with the destination network.
RIPv1 broadcasts only the elements in the routing table that have changed every 60 seconds.
RIPv1 does not include the subnet mask in its network advertisements.
A and D. Routers that are running the RIPv1 routing protocol broadcast their entire routing tables every 30 seconds, regardless of whether there has been a change in the network. RIP v1 does not include the subnet mask in its updates, so it does not support subnetting.
Which of the following is an example of a circuit-switched network connection, as opposed to a packet-switched network connection?
Two wireless computers using an ad hoc topology
A landline voice telephone call
A smartphone connecting to a cellular tower
Computers connected by a wired LAN
B. A circuit switched network connection requires a dedicated physical connection between the communicating devices. In a landline telephone call, a dedicated circuit is established between the two callers, which remains in place for the entire duration of the call. Wireless computers in an ad hoc topology and computers connected to a wired LAN use packet switching instead. A smartphone connection uses cell switching.
Which of the following mechanisms for prioritizing network traffic uses a 6-bit classification identifier in the Internet Protocol (IP) header? Diffserv CoS Traffic shaping QoS
A. Differentiated services (Diffserv) is a mechanism that provides quality of service on a network by classifying traffic types using a 6-bit value in the differentiated services (DS) field of the IP header. Class of Service (CoS) is a similar mechanism that operates at the data link layer by adding a 3-bit Priority Code Point (PCP) value to the Ethernet frame. Traffic shaping is a means of prioritizing network traffic that typically works by delaying packets at the application layer. Quality of service (QoS) is an umbrella term that encompasses a variety of network traffic prioritization mechanisms.
Which of the following is a network layer protocol that uses ICMPv6 messages to locate routers, DNS servers, and other nodes on an IPv6 network? BGP NDP OSPF PoE
B. The Neighbor Discovery Protocol (NDP) is a network layer protocol that defines five new Internet Control Message Protocol version 6 (ICMPv6) packet types, which enable IPv6 systems to locate resources on the network, such as routers and DNS servers, as well as autoconfigure and detect duplicate IPv6 addresses. Border Gateway Protocol (BGP) is an exterior gateway protocol that is designed to exchange routing information among autonomous systems. Open Shortest Path First (OSPF) is a link state routing protocol that enables routers to exchange routing table information. Power over Ethernet (PoE) is a general term for standards defining mechanisms for power delivery over Ethernet cables, along with data signals.
Which of the following is a protocol that identifies VLANs by inserting a 32-bit field in the Ethernet frame? IEEE 802.1P IEEE 802.1Q IEEE 802.1X IEEE 802.1AB
B. IEEE 802.1Q is a standard that defines a mechanism (called Ethernet trunking by some manufacturers) that identifies the virtual local area network (VLAN) to which a packet belongs by inserting an extra 32-bit field into its Ethernet frame. IEEE 802.1P is a standard that defines a mechanism for implementing quality of service (QoS) at the data link layer by adding a 3-bit field into Ethernet frames. IEEE 802.1X is a standard defining an authentication mechanism called port-based network access control (PNAC). IEEE 802.1AB is a standard defining the Link Layer Discovery Protocol (LLDP).
Which of the following is not an advantage of packet switching over circuit switching?
Packets can be transmitted out of order.
Packets can take different routes to the destination.
Packets can be stored temporarily in the event of network congestion.
Packets can be routed around areas of network congestion.
C. On a packet-switched network, packets can take different routes to the destination, can be transmitted out of order, and can be routed around network congestion. The packets are then reassembled into a complete message once all of them reach the destination. Temporary message storage is an advantage of circuit switching networks.
Which of the following statements about static routing are true? (Choose all correct answers.)
Static routes are manually configured routes that administrators must add, modify, or delete when a change in the network occurs.
Static routes are automatically added to the routing table by routing protocols when a new network path becomes available.
Static routes adapt to changes in the network infrastructure automatically.
Static routes are a recommended solution for large internetworks with redundant paths to each destination network.
Static routes are a recommended solution for small internetworks with a single path to each destination network.
A and E. Administrators must manually add, modify, or delete static routes when a change in a network occurs. For this reason, static routes are not recommended for use in large internetworks where there are multiple paths to each destination network. Static routes are not automatically added by routing protocols and do not adapt to changes in a network.
Which of the following TCP/IP routing protocols does not include the subnet mask within its route update messages, preventing it from supporting subnetting?
Routing Information Protocol, version 1 (RIPv1)
Routing Information Protocol, version 2 (RIPv2)
Border Gateway Protocol (BGP)
Open Shortest Path First (OSPF)
A. RIP v1 does not include the subnet mask in its updates. RIPv2 supports subnetting and includes the subnet mask of each network address in its updates. OSPF and BGP both include the subnet mask within their updates.
Which of the following terms refers to a routing protocol that does not rely on hop counts to measure the efficiency of routes? Interior gateway protocol Edge gateway protocol Distance vector protocol Link state protocol
D. Distance vector protocols rely on hop counts to evaluate the efficiency of routes. Link state protocols use a different type of calculation, usually based on Dijkstra’s algorithm. The terms interior gateway protocol and edge gateway protocol do not refer to the method of calculating routing efficiency.
What is the maximum number of routes that can be included in a single RIP broadcast packet? 20 25 32 Unlimited
B. A single RIP broadcast packet can include up to 25 routes. If there are more than 25 routes in the computer’s routing table, then RIP must generate additional packets.
Which of the following routing protocols can you use on a TCP/IP internetwork with segments running at different speeds, making hop counts an inaccurate measure of route efficiency? (Choose all correct answers.)
Enhanced Interior Gateway Routing Protocol (EIGRP)
Routing Information Protocol (RIP)
Open Shortest Path First (OSPF)
Border Gateway Protocol (BGP)
A and C. OSPF is a link state routing protocol, which means that it does not rely solely on hop counts to measure the relative efficiency of a route. EIGRP is a hybrid protocol that can use link state routing. RIP is a distance vector routing protocol, meaning that it uses hop counts to measure route efficiency. BGP is an exterior gateway protocol that exchanges routing information among autonomous systems using path vectors or distance vectors.
What is the term for the process by which dynamic routing protocols update other routers with routing table information? Convergence Distance vectoring Redistribution Dissemination
A. Convergence is the term for the process by which routers propagate information from their routing tables to other routers on the network using dynamic routing protocols. Distance vectoring, redistribution, and dissemination do not describe this process.
