2.3.8 Section Quiz

Question 1

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?

1. Segmentation
2. Encapsulation
3. Transformation
4. Sequencing

Answer 1

2. 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.

The Transport layer adds sequencing and control information.

The Internet layer converts the segments into packets.

Data flows down through the layers of the OSI model on the sending system and is transformed at each layer.

Question 2

What is the purpose of a frame check sequence (FCS) footer?

1. Contain logical network addresses
2. Checksum error detection
3. Hold segment data
4. Control information

Answer 2

2. 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.

Question 3

Which term does the OSI model use that’s different from the TCP/IP model in reference to the terms frame, packet, and segment?

1. Protocol data unit (PDU)
2. Session
3. Presentation
4. HTTP

Answer 3

1. Protocol data unit (PDU)

The OSI model uses the term protocol data unit (PDC) instead of the terms frame, packet, and segment.

The Presentation and Session layers are Layers 5 and 6 of the OSI model, respective y, and do not correspond to the use of frame, packet, and segment in the TCP/IP model.

Hyper Text Transfer Protocol (HTTP) is the protocol in the Application layer that supports web requests.

Question 4

What role does ARP play in the routing process?

1. If a router does not know a destination device’s MAC address, it sends an ARP broadcast containing the destination device’s
   address and requesting its MAC address.
2. ARP does not play any role in the routing process. Switches use ARP to map IP addresses to MAC addresses in collision
   domains.
3. If a router knows a destination host’s MAC and lP address, it sends an ARP request to update the other routers’ routing
   tables.
4. 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 it’s IP address

Answer 4

1. If a router does not know a destination device’s MAC address, it sends an ARP broadcast containing the destination device’s
   address and requesting its MAC address.

ARP (Address Resolution Protocol) resolves IP addresses into MAC addresses. Routers and other network devices use ARP when their routing tables don’t contain the MAC addresses of devices on the local LAN that they need to forward frames to.

Question 5

Routing data between computers on a network requires several mappings between different addresses. Which of the following statements is true?

1. Routers use ARP to resolve known IP addresses into MAC addresses.
2. ICMP lets routers bypass the general network broadcast by providing a dynamic table of IP-to-MAC address mappings.
3. Routers use DNS to resolve MAC addresses of diskless workstations into IP addresses based on the information contained in
   other routers routing tables.
4. Diskless workstations use ARP to ask a server for an address.

Answer 5

1. Routers use ARP to resolve known IP addresses into MAC addresses.

ARP lets routers resolve known IP addresses into MAC addresses by broadcasting requests to the network.

DNS is used to map hostnames to IP addresses. ARP is used to map IP addresses to MAC addresses.

Diskless workstations use BOOTP to discover their IP address, the servers IP address, and the boot files they should use.

CMP notifies routers of problems on the network and undeliverable packets.

Question 6

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?

1. UDP
2. HTTP GET
3. ARP
4. TCP

Answer 6

3. ARP

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

An HTTP GET requests web page information from a web server.

UDP and TCP are both Transport layer protocols.

Question 7

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?

1. SYN/RST
2. RST
3. SYN/ACK
4. ACK

Answer 7

3. 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.