Chapter 2

Which of the following tasks is associated with the Session layer? Answer Data block breakdown IP address assignment Port number assignment Connection establishment

Connection establishment Connection establishment is controlled through Session layer protocols.

You're configuring a network firewall to allow SMTP outbound email traffic and POP3 inbound email traffic. Which of the following TCP/IP ports should you open on the firewall? (Select two.) Answer 21 110 25 443 143

110 25 Simple Mail Transfer Protocol (SMTP) uses TCP/IP port 25. Post Office Protocol version 3 (POP3) uses TCP/IP port 110. File Transfer Protocol (FTP) uses TCP/IP port 21. Internet Message Access Protocol version 4 (IMAP4) uses TCP/IP port 143. Secure Sockets Layer (SSL) uses TCP/IP port 443.

You've recently installed a new Windows server. To ensure system time accuracy, you've loaded an application that synchronizes the hardware clock on the server with an external time source on the internet. Now you must configure your network firewall to allow time synchronization traffic through. Which of the following ports are you MOST LIKELY to open on the firewall? Answer 80 119 123 110

123 TCP/IP port 123 is assigned to Network Time Protocol (NTP). NTP is used to communicate time synchronization information between systems on a network.

Which port number is used by SNMP? Answer 25 110 119 161

161 Simple Network Management Protocol (SNMP) uses port 161. The other listed ports are used by the following protocols: SMTP uses port 25. POP3 uses port 110. NNTP uses port 119.

Which port does Telnet use? Answer 25 53 80 23

23 Telnet uses port 23. HyperText Transfer Protocol (HTTP) uses port 80. Simple Mail Transfer Protocol (SMTP) uses port 25. Domain Name System (DNS) uses port 53.

During network transmission, data is transferred to various routers, which forward the data to the appropriate network. If the source and destination network addresses reside on the same network, which protocol is used to determine the destination IP's MAC address? Answer UDP HTTP GET ARP TCP

ARP Address Resolution Protocol (ARP) is used to determine the host's MAC address using the destination IP address.

Match each networking function or device on the left with its associated OSI model layer on the right.

Application layer - HTTP Presentation layer - Translates data Session layer - Session ID number Transport layer - Port number Network layer - Router Data Link layer - Switch Physical layer - Modem

Which of the following topologies connects all devices to a trunk cable? Answer Bus Mesh Star Ring

Bus A bus topology connects all devices to a trunk cable.

What is the purpose of a frame check sequence (FCS) footer? Answer Contain logical network addresses Hold segment data Control information Checksum error detection

Checksum error detection The Link layer converts packets into frames, adding physical device addressing information and a frame check sequence footer for error detection. It also converts the frames into bits (0s and 1s) for transmission across the transmission media. Control information is added at the Transport layer. The Transport layer breaks the data into pieces called segments. The Internet layer converts the segments into packets, adding logical network and device addresses.

You've implemented a network where hosts are assigned specific roles, such as file sharing and printing roles. Other hosts access those resources, but they don't host services of their own. Which type of network do you have? Answer Peer-to-peer Extranet Client-server Intranet

Client Server In a client-server network, hosts have specific roles. For example, some hosts are assigned server roles, which allow them to provide network resources to other hosts. Other hosts are assigned client roles, which allow them to consume network resources.

Which of the following features does UDP provide? (Select two.) Answer Data packet sequencing Packet acknowledgement Connectionless datagram services Lost packet retransmission Low overhead

Connectionless datagram services Low overhead UDP is a connectionless protocol used by applications that need low overhead and don't require guaranteed delivery. TCP provides data packet sequencing, packet acknowledgement, and lost packet retransmission.

What is the basic purpose of the OSI Physical layer? Answer Coordinate rules for sending and receiving electrical signals. Define how physical network devices are identified on a network. Maintain a list of known networks and neighboring routers. Define when devices have access to the LAN

Coordinate rules for sending and receiving electrical signals. The OSI Physical layer sets standards for sending and receiving electrical signals between devices. The Data Link layer defines how physical network devices are identified on a network and when devices have access to the LAN. The Network layer maintains a list of known networks and neighboring routers.

In the OSI model, which of the following functions are performed at the Presentation layer? (Select two.) Answer Network services Data encryption and compression Data frame transmission Data format specifications End-to-end flow control

Data encryption and compression Data format specifications The Presentation layer encrypts data, changes and converts character sets, and compresses data. File formats (such as .jpg, .wmv, and .wav) are part of the Presentation layer.

Which of the following functions are performed by the OSI Transport layer? (Select three.) Answer Data segmentation and reassembly Path identification and selection Media access control, logical topology, and device identification Reliable message delivery Packet formatting for delivery through the medium Consistent data formatting between dissimilar systems End-to-end flow control

Data segmentation and reassembly Reliable message delivery End-to-end flow control

In the OSI model, which of the following functions are performed at the Application layer? (Select two.) Answer Communication setup, maintenance, and teardown. Enabling of communication between network clients and services. Standard setting for sending and receiving signals. Device control for data transmission rates. Integration of network functionality into the host operating system.

Enabling of communication between network clients and services Integration of network functionality into the host operating system.

Which of the following is the process of breaking a message into packets, adding controls and other information, and then transmitting the message through the transmission medium? Answer Transformation Sequencing Encapsulation Segmentation

Encapsulation Encapsulation is the process of breaking a message into packets, adding controls and other information, and then transmitting the message through the transmission medium.

Routing data between computers on a network requires several mappings between different addresses. Which of the following statements is true? Answer ICMP lets routers bypass the general network broadcast by providing a dynamic table of IP-to-MAC address mappings. Hosts use ARP to resolve known IP addresses into MAC addresses. Routers use DNS to resolve MAC addresses of diskless workstations into IP addresses based on the information contained in other routers' routing tables. Diskless workstations use ARP to ask a server for an IP address.

Hosts use ARP to resolve known IP addresses into MAC addresses.

Which of the following protocols allows hosts to exchange messages to indicate problems with packet delivery? Answer TFTP IGMP DHCP ICMP

ICMP Internet Control Message Protocol (ICMP) allows hosts to exchange messages to indicate a packet's status as it travels through a network.

Your manager has asked you to implement a network infrastructure that will accommodate failed connections. Which of the following network topologies provides redundancy for a failed link? Answer Star Ring Bus Mesh

Mesh In a mesh topology, each network device is interconnected with all other network nodes. This creates multiple data paths. If a link fails, the data has an alternate route to its destination

You have a network that uses a logical bus topology. How do messages travel through the network? Answer Messages are broadcast to all devices connected to the network. Messages travel from one device to the next until they reach the destination device. Messages are sent directly to the correct destination device. Messages are sent to a central device that forwards them to the destination devices.

Messages are broadcast to all devices connected to the network. Messages sent using a physical bus topology are broadcast to all devices on the network

You have a network that uses a logical ring topology. How do messages travel through the network? Answer Messages travel from one device to the next until they reach the destination device. Messages are sent directly to the destination device only. Messages are sent to all devices connected to the network. Messages are sent to a central device that forwards them to the destination devices.

Messages travel from one device to the next until they reach the destination device In a logical ring topology, messages travel to each device in turn. If the message isn't intended for that device, the message is forwarded to the next device on the network.

Which of the following geographic network types is typically managed by a city as a public utility? Answer Wide area network (WAN) Personal area network (PAN) Local area network (LAN) Metropolitan area network (MAN)

Metropolitan area network (MAN) A metropolitan area network (MAN) is a network that can cover an entire city. A city typically owns and manages a MAN as a public utility.

You have a large TCP/IP network and want to keep a host's real-time clock synchronized. Which protocol should you use? Answer FTP SNMP NTP SMTP

NTP Network Time Protocol (NTP) keeps computers' clocks synchronized.

You've implemented a network where each device provides all other devices on the network with access to shared files. Which type of network do you have? Answer Polling Multiple access Peer-to-peer Client-server

Peer-to-peer In a peer-to-peer network, each host can provide network resources to other hosts or access resources located on other hosts, and each host is in charge of controlling access to those resources.

Your manager has asked you to implement a wired network infrastructure that will accommodate failed connections. You don't have a large budget, so you decide to provide redundancy for only a handful of critical devices. Which of the following network topologies should you implement? Answer Star Bus Full mesh Partial mesh

Partial mesh In a partial mesh topology, only some redundant paths exist. A partial mesh topology is more practical and less expensive than a full mesh topology.

Which of the following are included as part of the Data Link layer specifications? (Select two.) Answer Physical topology Physical network device identification Digital data conversion Data transmission between hosts Cable and connector specifications

Physical network device identification Data transmission between hosts

Match each layer of the TCP/IP model on the left with the corresponding layer of the OSI model on the right. Each option on the left can be used more than once.

Presentation layer - Application Data Link layer - Network Application layer - Application Session layer - Application Network layer - Internetwork Transport layer - Transport

Which term does the OSI model use that's different from the TCP/IP model in reference to the terms frame, packet, and segment? Answer Presentation Protocol data unit (PDU) Session HTTP

Protocol data unit (PDU)

Which of the following topologies connects each device to a neighboring device? Answer Mesh Ring Star Bus

Ring In ring topologies, each device connects to a neighboring device so that a ring is formed.

In the OSI model, what is the primary function of the Network layer? Answer Route messages between networks. Transmit data frames. Enable communication between network clients and services. Ensure that packets are delivered with no loss or duplication.

Route messages between networks The Network layer is responsible for routing messages between networks. The Transport layer provides a transition between the upper and lower layers of the OSI model. The Data Link layer defines how to verify that data received from the Physical layer is error free (using parity and cyclic redundancy check [CRC]).

Your company has just acquired another company in the same city. You need to integrate the two email systems so that messages can be exchanged between email servers. Currently, each network uses an email package from a different vendor. Which TCP/IP protocol enables message exchange between systems? Answer POP3 IMAP4 ICMP SMTP

SMTP Simple Mail Transfer Protocol (SMTP) specifies how messages are exchanged between email servers. Email clients use POP3 and IMAP4 to download email messages from email servers.

TCP is a connection-oriented protocol that uses a three-way handshake to establish a connection to a system port. Computer 1 sends a SYN packet to Computer 2. Which packet does Computer 2 send back? Answer SYN/ACK SYN/RST ACK RST

SYN/ACK If Computer 1 sends a SYN packet to Computer 2, Computer 2 receives the packet and sends a SYN/ACK packet to Computer 1. Computer 1 receives the SYN/ACK packet and replies back with an ACK packet, and the connection is complete. A SYN flag is used to start a connection between hosts. An ACK acknowledges the receipt of a packet. An RST resets a connection.

You have a small network that uses a switch to connect multiple devices. Which physical topology are you using? Answer Star Ring Mesh Bus

Star A switch creates a network with a physical star topology. The physical star topology uses a logical bus topology and sends messages to all the devices connected to the hub.

You're an application developer, and you're writing a program for exchanging video files through a TCP/IP network. You need to select a transport protocol that will guarantee delivery. Which TCP/IP protocol provides this capability? Answer TCP FTP SIP UDP

TCP In this scenario, you should write the application to use Transmission Control Protocol (TCP). TCP guarantees delivery through error checking and acknowledgments.

Which of the following network services or protocols uses TCP/IP port 69? Answer POP3 NNTP SMTP TFTP

TFTP Trivial File Transfer Protocol (TFTP) uses TCP/IP port 69. TFTP is a connectionless service for downloading files from a remote system. It's often used for downloading firmware to networking devices.

During TCP/IP communication between two network hosts, information is encapsulated on the sending host and decapsulated on the receiving host using the OSI model. Match the information format on the left with the appropriate layer of the OSI model on the right. Transport layer Segments Network layer Packets Data Link layer Frames Physical layer Bits

Transport layer - Segments Network layer - Packets Data Link layer - Frames Physical layer - Bits

When does a router use ARP? Answer When the router's routing table doesn't contain the MAC addresses of devices on the local LAN that they need to forward frames to. If a router does not know a destination device's IP address, it sends an ARP broadcast containing the destination device's MAC address and requesting its IP address. If a router knows a destination host's MAC and IP address, it sends an ARP request to update the other routers' routing tables. ARP does not play any role in the routing process. Switches use ARP to map IP addresses to MAC addresses in collision domains.

When the router's routing table doesn't contain the MAC addresses of devices on the local LAN that they need to forward frames to.