Module 2 Quiz Flashcards
Match the protocol data unit (PDU) to its associated layer.
- Data - The general term for the PDU used at the application layer.
- Segment - Transport layer PDU.
- Packet - Internetwork layer PDU.
- Frame - Network access layer PDU.
-
Bits - A PDU used when physically transmitting data over the medium.
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The unit of data passed down the protocol stack (between layers) is referred to as a Protocol Data Unit (PDU). Every subsequent layer encapsulates the PDU it receives from the preceding layer according to the specifications of the protocol in use. At every layer, the PDU is referred to by a different name to reflect its current structure or function. The names are dependent on the protocol in use, but are widely aligned with naming inspired by the TCP/IP model (since it is so widely adopted):
Which of the following is a valid MAC address?
a.AC9.9A0.72A
b.ac;91;9a;0b;72;ad
c. ac9.91a.0b7.2ad
d.AC-91-9A-0B-72-AG
Drag the labels to identify the various aspects of the cable.
Jacket
Foil sheild
Braided Shield
Twisted pairs
Which of the following are benefits of segmentation? Marks are deducted for incorrect selections.
a. Sending smaller pieces at a time allows different conversations to be interleaved.
b. The delay of the communication is increased.
c. Sending smaller pieces at a time allows ensures that different conversations are sent separately.
d. The reliability of the communication is improved.
e. Larger pieces create less overhead on the CPU.
A good example of how various protocols interact to ensure that messages are delivered is in the communication between a web browser and a web server. The interactions between these protocols take place on four levels. Match the name of the level with its definition.
The Transmission Control Protocol (TCP) manages the conversation between the web server and client. It is also responsible for dividing the HTTP message into smaller chunks, called segments, and controlling the rate of communication.
Answer 1
Transport level
Protocols on this level convert the packet into a format that may be transmitted onto the network medium. Network interface cards need to be able to act as senders and receivers (transceivers) and must implement the standards required for communication on the specific media type.
Answer 2
Network access level
The Hypertext Transfer Protocol (HTTP) defines how the web server and browser (client) interact and how content is requested and delivered. HTTP is unable to transport the messages between the server and the client. It relies on other protocols for that.
Answer 3
Application level
On this level, the Internet Protocol (IP) is responsible for encapsulating the TCP segments into packets, addressing them and finding the best path through the network.
Answer 4
Internetwork level
In the following image A represents a
Straight‑through cable and B represents a Crossover cable .
When a group of protocols work in conjunction to facilitate communication, they are referred to as a protocol suite. These protocols may be implemented in hardware or software. Which of the following are types of processes described by networking protocol suites? Marks are deducted for incorrect selections.
a. The format or structure of the message.
b. The methods through which switches share routing information with mobile devices.
c. How and when error and system messages are passed between devices.
d. The creation of router configuration files.
When a group of protocols work in conjunction to facilitate communication, they are referred to as a protocol suite. These protocols may be implemented on hardware or software. Networking protocol suites describe processes such as:
- The format or structure of the message.
- The method by which networking devices share information about pathways with other networks.
- How and when error and system messages are passed between devices.
- The setup and termination of data transfer sessions.
State whether the following is true or false:
The TCP/IP model is a protocol model.
True
False
A networking model is very helpful in structuring the functions and protocols within a network in a way that is easier to understand by dividing the model into several categories or layers. Each layer includes protocols or standards that relate to that layer. Whereas the OSI model is considered to be a reference or more theoretical model, the TCP/IP model is a protocol model. Whenever you think of modern networking, chances are it is based on an implementation of the TCP/IP model.
The following image demonstrates the protocol stack for TCP/IP communications. Drag the labels to their correct position in the image.
Hypertext Transfer Protocol (HTTP)
Transmission Control Protocol(TCP)
Internet Protocol (IP)
A good example of how various protocols interact to ensure that messages are delivered is in the communication between a web browser and a web server. The interactions between these protocols take place on four levels:
Application level: The Hypertext Transfer Protocol (HTTP) defines how the web server and browser (client) interact and how content is requested and delivered. HTTP is unable to transport the messages between the server and the client. It relies on other protocols for that.
Transport level: The Transmission Control Protocol (TCP) manages the conversation between the web server and client. It is also responsible for dividing the HTTP message into smaller chunks, called segments, and controlling the rate of communication.
Internetwork level: On this level, the Internet Protocol (IP) is responsible for encapsulating the TCP segments into packets, addressing them and finding the best path through the network.
Network access level: Protocols on this level convert the packet into a format that may be transmitted onto the network medium. Network interface cards need to be able to act as senders and receivers (transceivers) and must implement the standards required for communication on the specific media type.
Which of the following is seen as functionality provided by the physical layer? Marks are deducted for incorrect selections.
Select one or more:
a. Creation of frames
b. Encoding of data and control information
c. Routing IP packets
d. Physical media and associated connectors
State whether the following is true or false:
Rules that govern communication are commonly referred to as protocols.
Select one:
True
False
Most activities in the real and digital world are governed by rules; this includes the act of communication. These rules that govern communication are commonly referred to as protocols.
Match the MAC sublayer responsibility with its definition.
Because Ethernet is a shared media and all devices can transmit at any time, media access is controlled by a method called Carrier Sense Multiple Access with Collision Detection (CSMA/CD) when operating in half-duplex mode.
Answer 1
Media Access Control
Includes frame assembly before transmission, frame parsing upon reception of a frame, data link layer MAC addressing and error detection.
Answer 2
Data encapsulation
When focusing on Ethernet networks, the MAC sublayer has two primary responsibilities:
- Data encapsulation: Includes frame assembly before transmission, frame parsing upon reception of a frame, data link layer MAC addressing and error detection.
- Media Access Control: Because Ethernet is a shared media and all devices can transmit at any time, media access is controlled by a method called Carrier Sense Multiple Access with Collision Detection (CSMA/CD) when operating in half-duplex mode.
State whether the following is true or false:
Single mode fiber is capable of higher bandwidth and greater distances than multimode and is often used for campus backbones.
Select one:
True
False
Fiber optic cable is more expensive than coaxial or twisted-pair cable, but it supports higher rate line speeds. Since it is light-based, it is not susceptible to EMI. It is also more secure than other means of transmission since - unlike electrical signals - external devices cannot intercept the signal. Broadly speaking, two types of fiber optic cable exist:
- Single mode - allows only one mode (or wavelength) of light to propagate through the fiber. This type of cable is capable of higher bandwidth and greater distances than multimode and is often used for campus backbones. Single mode cable uses lasers as the light-generating method and is more expensive than multimode cable.
- Multimode - allows multiple modes of light to propagate through the fiber. Multimode cable is often used for workgroup applications, using light emitting diodes (LEDs) as light-generating devices.
State whether the following is true or false:
Network models are a means of ensuring that devices are able to interoperate, whereas standards create a shared vocabulary (or common language) to describe networking functions.
Select one:
True
False
Which of the following is not a benefit of using a layered model to describe networking?
Select one:
a.Networkers all over the world would have knowledge of the same layered models, which provides a shared vocabulary for discussion and troubleshooting.
b.It allows companies to devise their own proprietary implementations without having to adhere to interoperability standards.
c.Along with standards, it allows for products of different vendors to interact, so it fosters competition.
d.Changes are compartmentalised, so an update in one layer should not affect another.
Using a layered model to describe networking has the following benefits:
- It assists in protocol design, because the functioning of the protocol is devised specifically for the tasks required at the specific layer, and it allows for interfaces to be defined for connection (passing of information) between layers.
- Along with standards, it allows for products of different vendors to interact, so it fosters competition.
- Changes are compartmentalised, so an update in one layer should not affect another.
- Networkers all over the world would have knowledge of the same layered models, which provides a shared vocabulary for discussion and troubleshooting.
