CS402: Computer Communications and Networks Certification Final Exam Answers

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Question 1: The networking standards development process is documented by:

• ISO standards.
• a protocol.
• an RFC.
• a standar

Question 2: Which transmission mode should be used to send information from a single point to another point?

• Anycast
• Broadcast
• Multicast
• Unicast

Question 3: In a complete data transmission (request and response), the diagram would contain which of the following?

• Two layers
• Five layers
• Two columns with matching layers.
• Five columns with matching layers.

Question 4: A LAN typically interconnects devices located where?

• Anywhere on Earth
• In your city
• In your house
• Within 10 meters of one another

Question 5: What is the network that typically interconnects devices with network capabilities located anywhere on Earth?

• Internet
• LAN
• PAN
• WAN

Question 6: Which of the following network topologies would reduce network failure by connecting all the network nodes to a central node?

• Bus
• Ring
• Star
• Tree

Question 7: What is the RFC?

• A database of Internet services
• A numeric linking system used by your text
• A numeric listing of TCP/IP protocols
• A tracking system for network development requirements

Question 8: Which of the following layers is unique to the TCP/IP reference model?

• Application
• Internet
• Transport
• VoIP

Question 9: The protocols for email and web file access are described in which layer of the Internet protocol?

• Network
• Presentation
• Session
• Transport

Question 10: Which of the following is a characteristic of the TCP service?

• It is authenticate
• It is bidirectional.
• It is connectionless.
• It is unreliable.

Question 11: An element of the WWW protocol is:

• HTML.
• JavaScript.
• Jav
• XML.

Question 12: The ______ access layer in the TCP/IP reference model is the combination of the Application, Presentation, and Session layers in the OSI reference model.

• Application
• Internet
• Network
• Transport

Question 13: The application layer in the TCP/IP reference model is different from which layer in the OSI model?

• Application
• Communication
• Presentation
• Session

Question 14: Which of the following layers is a combination of the Application, Presentation, and Session layer in the TCP/IP reference model?

• Application
• Internet
• Network Interface
• Transport

Question 15: The OSI Reference Model layers, in order from top to bottom, are:

• Application, physical, session, transport, network, data link, presentation.
• Application, presentation, network, session, transport, data link, physical.
• Application, presentation, session, transport, network, data link, physical.
• Physical, data link, network, transport, session, presentation, application.

Question 16: Which of the following is a protocol used to retrieve email messages?

• MTP
• POP
• SMTP
• SNMP

Question 17: The most widely used application/programming interface for UDP is the:

• ADU.
• layer.
• socket.
• telnet.

Question 18: A MIME message must:

• identify spam.
• be in binary format.
• allow audio/video transmissions.
• support only one format in a single message.

Question 19: Which of the following describes SMTP?

• It utilizes UDP.
• It allows web access.
• It answers with multi-line replies.
• It relies on the client-server model.

Question 20: PPP utilizes which of the following?

• Bit stuffing for asynchronous lines
• Character stuffing for synchronous lines
• CRC for error detection
• CRC for error ion

Question 21: What is the unit of information exchanged between two entities in the application layer?

• An ADU
• A bit
• A datagram
• A packet

Question 22: As a network engineer, you are required to write a simple socket program. What are the parameters you need to specify while creating a socket?

• Socket address and socket family
• Socket message and socket header
• Socket stream and datagram socket
• Socket type and address domain

Question 23: The HTTP request header:

• contains no-cache.
• contains no-transform.
• allows client information.
• contains the date, server, and content information.

Question 24: The HTTP response header:

• allows client information.
• contains the data file content information.
• contains the status and content information.
• contains the date, server, and content information.

Question 25: The function of Domain Name System is to:

• route the IP packet to the destination.
• translate computer hostnames to IP addresses.
• translate IP addresses to computer hostnames.
• automatically assign IP address to network device.

Question 26: Which of the following best describes the Stream Control Transmission Protocol (SCTP)?

• Reliable, message-oriented
• Reliable, character-oriented
• Unreliable, message-oriented
• Unreliable, character-oriented

Question 27: A connectionless service can be modeled by using just two primitives containing the SDU parameter. What information is contained in the SDU?

• The message
• The source address
• The address of the sender
• The address of the recipient

Question 28: A connection-oriented transport protocol is:

• Frame Relay.
• ICMP.
• IPX.
• TIP

Question 29: What is the unit of exchange in the transport layer?

• Bits
• Data
• Packets
• Segments

Question 30: A random isolated error in a segment in the transport layer occurs when:

• one bit flips.
• a group of bits flip.
• two consecutive bits flip.
• most bits in the segment flip.

Question 31: How many bits are needed for the Alternating Bit Protocol?

• 1
• 3
• 5
• 7

Question 32: The ___ layer is responsible for ensuring that messages are delivered in sequence and with no duplication.

• Application
• Network
• Physical
• Transport

Question 33: The network layer allows your LAN to exchange information with other networks through an intermediate system called a:

• datagram.
• frame.
• packet.
• router.

Question 34: All client computers are configured to receive IP addresses from the DHCP server. However, clients on Subnet B cannot access clients on Subnet  What is the most likely cause of this problem?

• IPv6 is disable
• Server option is disable
• The IP address is not available in DHCP scope.
• The IP address for the DNS Server is not available in scope option.

Question 35: For the subnet mask bits /31, what is the number of /24 subnets?

• 2
• 8
• 64
• 128

Question 36: For the subnet mask bits /24, what is the number of /25 subnets?

• 1
• 2
• 4
• 8

Question 37: The EGP protocol exchanges routing information between autonomous systems. Which of the following is an exterior gateway protocol?

• BGP.
• EIGRP.
• OSPF.
• RIP.

Question 38: Which of the following statements best describes middlebox devices?

• A firewall is a type of middlebox device.
• Middlebox devices operate only in the network layer.
• Middlebox devices are routers that process, modify, and forward IP packets.
• Middlebox devices act as network hubs that forward data to multiple devices.

Question 39: The purpose of the ICMPv4 is to do which of the following?

• Calculate MTU
• Determine protocol
• Determine destination
• Generate an error message

Question 40: Most data link protocols use:

• a checksum.
• traffic control.
• a port number.
• a user passwor

Question 41: Which type of cable is found in a public network?

• Coaxial
• Optical fiber
• Plenum cable
• Twisted pair

Question 42: What might you use to describe the interactions between the users and the provider of a computer network?

• Algorithms
• Hashing
• Primitives
• Time-sequence diagrams

Question 43: Which of the following protocol is designed to improve CSMA performance by terminating transmission as soon as a collision occurs?

• ALOH
• CSMA/C
• CSMA/C
• VTCSM

Question 44: Which of the following is one of the CSMA access modes that supports an aggressive transmission algorithm?

• 1-persistent.
• 2-persistent.
• 3-persistent.
• 4-persistent.

Question 45: Which of the following statement about the physical layer protocol is true?

• The physical layer uses the port number to deliver traffi
• The physical layer changes the value of a bit being transmitted due to electromagnetic interference.
• The physical specifies the shared protocols and interface methods used by hosts in a communications network.
• The physical layer provides the mechanism for opening, closing, and managing a session between end-user application processes.

Question 46: The unit of information for transfer between two entities of the data link layer is a:

• bit.
• channel.
• frame.
• packet.

Question 47: Which OSI layer breaks data up into individual frames to prepare it for transfer across a network?

• Data link
• Network
• Session
• Transport

Question 48: Which transmission mode is used to send a video or radio signal in a TV transmission over your LAN?

• Anycast
• Broadcast
• Multicast
• Point-to-point transport

Question 49: ___ is a cloud computing solution that is implemented outside the company’s firewall and is under the control of a third party.

• Public cloud
• Private cloud
• Platform as a service
• Software as a service

Question 50: ___ allows developers to develop and test an application without worrying about the underlying infrastructure and ___ provides storage, infrastructure, and connectivity to a consumer.

• IaaS, SaaS
• PaaS, IaaS
• SaaS, PaaS
• SaaS, IaaS

Question 51: How are the interactions between a user and a service provider expressed as an abstract representation?

• Checksum
• Hashing
• Parity
• Primitive

Question 52: The networking process for review and revision is documented by a:

• protocol.
• RFC.
• standard.
• W3C publication.

Question 53: The data link layer provides reliable delivery of information due to its _____.

• connection-oriented characteristics
• error detection
• fixed-length frames
• media access control

Question 54: What is the network topology typically used by cable TV networks?

• Bus
• Ring
• Star
• Tree

Question 55: Throughout this course, you have been asked to understand a number of concepts underlying the computer networks. Which of the following statements best sums up these concepts?

• Different types of devices enable all hosts to exchange information.
• Information sent on computer networks always reaches its destination.
• Protocols are the processes that occur in the computer networks.
• Protocols are used to make phone calls over computer networks.

Question 56: The physical layer delivers 1000 bits to the receiver. However, the receiver only receives 900 bits. Which of the following characteristics describes the behavior of the physical layer?

• Compressed
• Error-free
• Reliable
• Unreliable

Question 57: A service provided by the physical layer is:

• user authorization.
• transmission of long messages.
• the transfer of data frames from one node to another.
• bit transmission between nodes attached to the same physical transmission channel.

Question 58: How many layers comprise the OSI Model?

• 3
• 5
• 7
• 9

Question 59: The session layer in the OSI reference model is similar to which layer in the TCP/IP model?

• Application
• Internet
• Routing
• Session

Question 60: A manager is a host that runs which of the following SNMP processes?

• Client
• Server
• TCP
• UDP

Question 61: A(n) _____ query is defined as a query for the domain name that corresponds to a given IP address.

• Reverse
• Resource
• Robust
• Zone

Question 62: The most widely used application/programming interface for TCP is the:

• ADU.
• layer.
• socket.
• telnet.

Question 63: The syntax used in the URL requires the:

• IP address.
• HTTP protocol.
• document location.
• web server details.

Question 64: Which of the following is a main entity in the client-server environment?

• Network
• Peer-to-peer
• Routing
• Switching

Question 65: Which of the following does SNMP define to be sent from a manager to an agent and vice versa?

• Username
• Number of packets
• Format of the packets
• Encoding of the packets

Question 66: Select the correct order of mail transfer phases in SMTP protocol.

• Authorization, establish a connection, mail transfer
• Mail transfer, authorization, connection termination
• Authentication, mail transfer, connection termination
• Establish a connection, mail transfer, connection termination

Question 67: Which of the following describe the features that are supported by the transport layer?

• Connection-oriented, flow control, and multiplexing
• Data encoding, frame error checking, and session support
• Frame fragmentation, file sharing, and network management
• Remote file access, data encryption, and media access control

Question 68: A complex solution to detect transmission errors is:

• even parity.
• Internet checksums.
• error-correcting codes.
• cyclical redundancy check.

Question 69: The IP subnet address can be represented as a(n):

• address.
• CIDR.
• interface.
• netmask.

Question 70: How does CSMA/CD react to collisions?

• Collisions do not occur on CSMA/CD.
• All systems jam the network, and then all begin transmitting again.
• Hosts involved in a collision send an RTS signal indicating a time frame in which to retransmit.
• Hosts involved in the collision send a jam signal, and then run an algorithm before retransmitting.

Question 71: Which of the following is a communication protocol that uses a three-byte frame that travels around a logical ring of workstations or servers?

• CSMA/CA
• CSMA/CD
• Frame ring
• Token ring

Question 72: What is the size of a MAC address?

• 16 bits
• 32 bits
• 48 bits
• 64 bits

Question 73: All client computers are configured to receive IP addresses from the DHCP server. However, clients on Subnet B cannot access clients on Subnet A. What is the most likely cause of this problem?

• IPv6 is disabled.
• Server option is disabled.
• The IP address is not available in DHCP scope.
• The IP address for the DNS Server is not available in scope option.

Question 74: For the subnet mask bits /28, what is the number of addresses?

• 12
• 14
• 16
• 28

Question 75: Which of the following networking protocols is used to transfer files between a client and server on a computer network and secured with SSL or SSH authentication?

• ICMP
• FTP
• TCP
• UDP

Question 76: What is the unit of information transferred in the physical layer?

• Bit
• Datagram
• Fragment
• Packet

Question 77: Which of the following is a connectionless transport protocol?

• SCTP
• TCP
• Telnet
• UDP

Question 78: The UDP service is characterized by:

• its reliability.
• being connectionless.
• its unlimited message size.
• its user authentication method.

Question 79: The ICMPv6 is used by the data link layer to:

• autoconfigure addresses.
• determine the packet is too big.
• determine the address is unreachable.
• determine transmission time is exceeded.

Question 80: Select the network service that allows a host to retrieve its assigned IPv4 address automatically.

• ARP
• DHCP
• DNS
• RARP

Question 81: A security issue in the transport layer occurs when:

• a virus is spread.
• the packet is lost in transmission.
• the checksum algorithm detects an error.
• the information becomes corrupted by a non-transmission error.

Question 82: Which statement best describes a host name?

• It replaces the IP address.
• t is assigned by the IETF.
• It is composed of two parts.
• It does not have to be unique

Question 83: In a reliable connectionless service, packets:

• cannot be lost.
• can be modified.
• can be duplicated.
• can suffer transmission errors.

Question 84: Which of the following fields is found in an IPv4 header but not in an IPv6 header?

• IHL.
• Source address.
• Destination address.
• TTL or Hop Limit.

Question 85: Your LAN is running a Voice over IP application that is processing slowly, or not at all. You have determined that it is due to the IPv6 header overhead. Which of the following techniques/services will best resolve the issue?

• Data compression
• Data fragmentation
• Data reassembly
• Data reorganization

Question 86: Which of the following belongs to the link layer?

• LAN devices
• MAC addresses
• NBMA networks
• Point-to-point links

Question 87: A distributed algorithm can be used for:

• concurrent processing.
• preventing packet loss.
• delaying transmissions.
• creating recovery messages.

Question 88: Which layer from OSI layer model facilitates the creation, sending, and receiving of bits?

• Data link
• Physical
• Session
• Transport

Question 89: The ICMPv6 protocol is configured in your network but is giving destination unreachable ICMP messages. Which of the following

• could be responsible for destination unreachable error messages?
• hop limit exceeded in transit
• beyond the scope of source address
• erroneous header field encountered
• fragment reassembly time exceeded

Question 90: Each end of the TCP connection uses a buffer to speed up data flow when the network is busy. Which of the following processes manages the flow controls?

• Buffer control
• Sliding window
• Traffic avoidance
• Congestion control

Question 91: What does the receiver use to extract frames from the bit stream?

• Big endian
• Character stuffing
• MAC padding
• Reverse lookup

Question 92: Amazon provides ___ cloud computing and Microsoft supports the ___ cloud computing model.

• Azure, EC2
• EC2, Azure
• Deep Blue, EC2
• Deep Blue, Azure

Question 93: Select the correct architecture in which each host can simultaneously act as both a client and a server.

• Client-server
• Client-queue-client
• Client-server three-tier model
• Peer-to-Peer

Question 94: Which of the following is an example of a client-server protocol?

• IP
• LCP
• NCP
• SIP

Question 95: A reliable transport layer includes:

• DNS lookup.
• user authentication.
• IP packet forwarding.
• connection establishment.

Question 96: When a router receives a packet, the router does which of the following?

• Checks the digital signature
• Performs network address translation
• Store the state information about the packet
• Forwards the data packets between computer networks

Question 97: A radio signal can be sent using which of the following?

• Bluetooth
• Coaxial cable
• Optical fiber
• Wireless network

Question 98: A MAC address is an example of the:

• application layer.
• data link layer.
• physical layer.
• transport layer

Question 99: Which of the following is a phase of the POP protocol?

• Authorization
• Closure
• Handshaking
• Transmission

Question 100: The language used to encode documents on the web is:

• HTML.
• HTTP.
• Unicode.
• XML.

Question 101: A deadlock occurs in the transport layer when the:

• segment is lost.
• checksum result is invalid.
• transmission error is random.
• data transmission is bidirectional.

Question 102: A random burst error in a segment of the transport layer occurs when:

• one bit flips.
• a group of bits flip.
• using UDP instead of TCP.
• most bits in the segment flip

Question 103: A _____ cable has an insulator that minimizes the emission of dangerous fumes in the event of fire.

• coaxial
• plastic
• STP twisted pair
• UTP twisted pair

Question 104: A great resource used by network maintenance/support personnel when researching the evolution of a protocol is/are the:

• Cisco standards.
• IEEE.
• RFC.
• vendor device manual.

Question 105: The presentation layer in the OSI reference model is similar to which layer in the TCP/IP model?

• Application
• Internet
• Presentation
• Session

Question 106: The hop limit field in IPv6 has the same purpose as which field in the IPv4 header?

• Extension header
• MTU
• TTL
• UDP

Question 107: The Internet layer in the TCP/IP reference model is the equivalent to which layer in the OSI model?

• Application
• Data link
• Network
• Transport

Question 108: Which of the following protocols runs on TCP port 22 and operates network services securely over an unsecured network?

• CyberGate
• SGMP
• SSH
• TACACS+

Question 109: It is often necessary to exchange information between hosts that are not attached to the same physical medium. Which layer’s basic function is to facilitate this exchange?

• Data link
• Network
• Physical
• Transport

Question 110: Your LAN is running a Voice over IP application that is processing slowly, or not at all. You have determined that it is due to the IPv6 header overhead. Which of the following techniques/services will best resolve the issue?

• Data compression
• Data fragmentation
• Data reassembly
• Data reorganization

Question 111: Which of the data link layer protocols supports retransmission of lost or corrupted messages?

• Token ring
• Alternating bit protocol
• Address routing protocol
• Asynchronous transport mode

Question 112: Which of the following is an element of the WWW protocol?

• DHCP
• DNS
• HTML
• XML

Question 113: The layer that builds on the service provided by the underlying physical layer is the:

• data link layer.
• network layer.
• transport layer.
• physical layer.

Question 114: The TCP/IP reference model combines the data link and another layer in its link layer. What is the second layer?

Select one:

• Application
• Network
• Physical
• Transport

Question 115: he ICMPv6 protocol is configured in your network but is giving destination unreachable ICMP messages. Which of the following could be responsible for destination unreachable error messages?

Select one:

• hop limit exceeded in transit
• beyond the scope of source address
• erroneous header field encountered
• fragment reassembly time exceeded

Question 116: An address is considered CIDR if the address or routing prefix is written with a suffix indicating the number of bits of the prefix. Select the correct CIDR notation from the following list.

Select one:

• 192.168.0.1
• 192.168.1.1/24
• 192.168.1.1 255.255.255.0
• 255.255.255.0