Question 1

One of the problems that can occur in the Network layer is the incorrect configuration of a host's IP address.

Accepted Answer

If a host has an incorrect IP address configured, it may not be able to communicate with other hosts on the network or correctly route its packets to the correct destination. This can cause connectivity problems and network issues.

Question 2

What does the Transport layer use to make sure that a message is reassembled correctly on the receiving device?

Accepted Answer

The Transport layer uses sequence numbers to make sure that a message is reassembled correctly on the receiving device. Sequence numbers ensure that all segments are put back in the correct order, and any missing or duplicate segments can be identified and dealt with appropriately. Source port number, destination port number, and window size are important for other aspects of Transport layer communication, but do not directly contribute to message reassembly.

Question 3

The maximum transmission unit for Ethernet is 1518 bytes.

Accepted Answer

This is true, the maximum transmission unit (MTU) for Ethernet is 1518 bytes.

Question 4

One job that a router performs is that of gatekeeper, which means that it can be configured to only allow certain packets access into the network based on a list of rules. What is that process called?

Accepted Answer

The process of allowing certain packets access into the network based on a list of rules is called access control. Option A, media control, refers to the regulation of the flow of media, such as audio or video. Option B, packet forwarding, is the process of transferring data packets from one network to another. Option D, signal bounce, does not relate to the given question at all.

Question 5

The Network layer communicates with the Data Link layer and the Session layer.

Accepted Answer

The Network layer communicates directly with the Data Link layer below it and the Transport layer above it, not the Session layer.

Question 6

What information would you find in the header of a Transport layer PDU?

Accepted Answer

The Transport layer PDU (Protocol Data Unit), specifically in protocols like TCP (Transmission Control Protocol), includes control information such as window size. The window size is used for flow control, indicating how much data the receiver is willing to accept.

Question 7

You are working at the help desk and you get a message that a user cannot access the Internet. You open a command prompt, ping the workstation's IP address, and get a response. You ask the user to try the Internet again. He does so with the same result-no connection. Which type of device is most likely to be the problem?

Accepted Answer

Since the workstation's IP address responded to the ping request, it indicates that the physical layer and data link layer devices (such as the network interface card and switch) are functioning properly. The issue is likely at the network layer, which could include the router or firewall preventing the user from accessing the Internet. The presentation layer is responsible for formatting data and is not involved in network connectivity issues.

Question 8

At each layer of the OSI model, data is appended to the original message and then sent on to the next lower layer. What is this process called?

Accepted Answer

The process of appending data to the original message at each layer of the OSI model is called encapsulation. This process helps to add the necessary information to the data so that it can be transmitted across the network.

Question 9

Which layer is responsible for establishing communication setup between the source and destination computers?

Accepted Answer

The session layer is responsible for establishing communication setup between the source and destination computers.

Question 10

At what layer do NICs operate?

Accepted Answer

NICs (Network Interface Controllers) operate at the Data Link layer of the OSI model. This layer is responsible for providing error-free transfer of data between two devices on the same network. NICs use MAC addresses to uniquely identify devices on a network and ensure data is sent to the correct destination.

Question 11

You are using tracert to determine the path a packet takes across your internetwork. Which OSI Model layer are you examining?

Accepted Answer

Tracert is a tool that helps to trace the path of a packet by sending ICMP (Internet Control Message Protocol) packets with increasing TTL (Time to Live) values. This allows us to examine the routers and their interfaces that a packet passes through to reach its destination. As this involves examining the routing table and forwarding decisions made by the routers, it falls under the Network layer of the OSI model.

Question 12

What is the IEEE standard that governs all forms of Ethernet media and interfaces?

Accepted Answer

IEEE 802.3 standard governs all forms of Ethernet media and interfaces, including copper wires, coaxial cables, and fiber optic cabling.

Question 13

What is a PDU?

Accepted Answer

PDU stands for Protocol Data Unit, which is the unit of information used by each layer in the OSI model to communicate with the layer above or below it. Each layer adds its own header to the PDU received from the layer above it, forming a new PDU that gets passed down to the next layer. Therefore, the term PDU is not specific to any particular layer but rather a general term that refers to the unit of information used by each layer.

Question 14

The IEEE separated the OSI model Physical layer into the LLC sublayer and the MAC sublayer.

Accepted Answer

The IEEE separated the OSI model Data Link layer into the LLC sublayer and the MAC sublayer, not the Physical layer.

Question 15

Which layer of the OSI model is responsible for protocol conversion, if necessary?

Accepted Answer

The Presentation layer in the OSI model is responsible for protocol conversion, if necessary. This layer is responsible for translating data into a form that can be understood by the application layer. It also handles encryption, compression, and formatting of data, as well as managing data syntax and semantics. Therefore, option B is the best choice as it specifically mentions the layer responsible for protocol conversion.

Question 16

Which of the following is the correct order of the layers of the OSI model from layer 1 to layer 7?

Accepted Answer

The correct order of the layers of the OSI model is from bottom to top: Physical, Data Link, Network, Transport, Session, Presentation, Application.

Question 17

The Transport layer is the same in both the OSI model and the TCP/IP model.

Accepted Answer

The Transport layer (layer 4) operates in the same way in both the OSI model and the TCP/IP model. It is responsible for ensuring reliable data transmission between end-to-end hosts and providing flow control, error correction, and congestion control mechanisms. However, the protocol names and specifications at this layer differ in the two models, with TCP (Transmission Control Protocol) and UDP (User Datagram Protocol) being the most commonly used protocols in the TCP/IP model, while the OSI model specifies protocols such as TP0, TP1, TP2, and TP3 for this layer.

Question 18

What layer is responsible for making sure that the data that it sends and receives is in a format that the receiving and sending computers can understand?

Accepted Answer

The answer of What layer is responsible for making sure...

Question 19

What is the IEEE standard that sets the standards for wireless networking?

Accepted Answer

IEEE standard 802.11 sets the standards for wireless networking, including Wi-Fi.

Question 20

What function does the Logical Link Control sublayer of the Data Link layer provide?

Accepted Answer

The Logical Link Control (LLC) sublayer is responsible for error recovery and flow control. It ensures that data is transmitted correctly and in the right order. The other options are functions of other layers or sublayers within the network stack.

Quiz 7: Network Reference Models and Standards