Network and Security - Foundations -
D315 with complete solutions 2025.
What are the two primary protocols used in networking? - ANSWER: TCP and IP
What are the four layers of the TCP/IP model in descending order? - ANSWER: 1. Application
(top)
2. Transport
3. Network
4. Network Interface (bottom)
What are the seven layers of the OSI model in ascending order? - ANSWER: 1. Physical
(bottom)
2. Data link
3. Network
4. Transport
5. Session
6. Presentation
7. Application
What are basic characteristics of the Transmission Control Protocol (TCP)? - ANSWER: TCP is
reliable in terms of delivery as it verifies the data and resends it if not delivered.
What are some characteristics of User Datagram Protocol (UDP) - ANSWER: UDP is unreliable
as it doesn't guarantee redelivery of the data?
What is a brief synopsis of the Application layer in the TCP/IP model for networks? - ANSWER:
The Application layer is responsible for the communication protocols between nodes. The
protocols in this layer include Hypertext Transfer Protocol (HTTP and HTTPS), Secure Shell
(SSH), and Network Time Protocol (NTP), among many others.
What is a brief synopsis of the Transport layer in the TCP/IP Protocol? - ANSWER: The
Transport layer is responsible for the end-to-end transport of data. The protocols that live in this
layer are the Transmission Control Protocol (TCP) and User Datagram Protocol (UDP)
,What is a brief synopsis of the Network layer in the TCP/IP Protocol? - ANSWER: The Network
layer defines the logical transmission protocols for the whole network. The main protocols that
live in this layer are the Internet Protocol (IP), Internet Control Message Protocol (ICMP), and
the Address Resolution Protocol (ARP).
What is a brief synopsis of the Network Interface Protocol? - ANSWER: The Network Interface
layer establishes how data should be physically sent through the network.
What is a quick synopsis of Layer 7 in the Open Systems Interconnection (OSI) model? -
ANSWER: The Application layer is Layer 7. It is responsible for network applications (like HTTP
or FTP) and their production of data to be transferred over the network.
What is a quick synopsis of Layer 6 in the Open Systems Interconnection (OSI) model? -
ANSWER: The Presentation layer is Layer 6. It is responsible for translating data from the
application layer into the format required to transmit the data over the network as well as
encrypting the data for security if encryption is used.
What is a quick synopsis of Layer 5 in the Open Systems Interconnection (OSI) model? -
ANSWER: The session layer is Layer 5. It is responsible for connection establishment, session
maintenance, and authentication.
What is a quick synopsis of Layer 4 in the Open Systems Interconnection (OSI) model? -
ANSWER: The Transport layer is Layer 4. It provides services to the application layer and
receives services from the network layer. It is responsible for reliable delivery of data. It
segments and reassembles data in the correct order for the receiving device. It may also handle
the reliable delivery of data and any retries of data that are lost or corrupted (for example, TCP
does this). This layer is often called the heart of the OSI.
What is a quick synopsis of Layer 3 in the Open Systems Interconnection (OSI) model? -
ANSWER: The Network Layer is Layer 3. It is responsible for the transmission of data between
hosts in different networks as well as the routing of data packets. This layer is implemented in
routers and some switches.
What is a quick synopsis of Layer 2 in the Open Systems Interconnection (OSI) model? -
ANSWER: The Data Link is layer 2. That Data Link layer is responsible for the delivery of data
to the receiving device or node. This layer is implemented in switch and bridge devices as well
as anything with a network interface, like a wireless or wired network card.
What is a quick synopsis of Layer 1 in the Open Systems Interconnection (OSI) model? -
ANSWER: The Physical is layer 1. It is responsible for the physical connections of the devices
in the network. This layer is implemented in hub, repeater, modem devices, and physical
cabling.
,Which transmission control protocol/internet protocol (TCP/IP) layer performs addressing and
routing? - ANSWER: The correct answer is The Network layer. It handles addressing and
routing to different networks.
Which layer of the OSI model does a bridge to make decisions about forwarding packets? -
ANSWER: The correct answer is the Data Link layer. It represents network communication at a
MAC-address level and forwards packers to Layer 2 devices, like a bridge.
Which layer of the OSI model establishes, manages, and terminates connections? - ANSWER:
The correct answer is the Session layer. It establishes, manages, and terminates connections.
What is a modem? - ANSWER: A modem is a device necessary for sending and receiving data.
Modems allow computers to transport digital information over analogue lines, such as phone or
cable lines. Types of modems include cable modems, DSL modems, and satellite modems.
What is a router? - ANSWER: A router is a point of connection between two or more networks
that forwards data packets between the networks. To have internet in your home, you need an
internet router that connects the networks on the internet to the network of your home.
You can access the internet's network either through a wired Ethernet port or via Wi-Fi.
What is a switch? - ANSWER: A switch is used to connect devices in a specific network and
allows them to communicate efficiently within the network. A switch is a more complex version
of a hub, in that switches have the capability to add security measures and function far more
intelligently, sending traffic directly from the sender to the receiver without other devices being
aware of the communication.
Thus, a switch is less chatty and allows for more simultaneous conversations between devices.
Most internet routers include a switch in the form of wired and wireless Ethernet connections.
What is bridge, in an IT context? - ANSWER: A bridge is similar to a router in that it connects
two or more networks. The difference is that a router analyzes data packets to determine where
to send the packet next, whereas a bridge simply forwards the data to the next network without
analysis.
This makes for fast data transfer that lacks versatility. Bridges are not widely used in modern
networks, as routers and switches are the favored devices.
What is a repeater? - ANSWER: A repeater is a device used to strengthen, replicate, and
regenerate signals that are weakened (for example, because of distance) during transmission.
In many large homes, the Wi-FI signal does not extend to the end of the house farthest from the
router.
, A range extender is a form of repeater that takes the distorted Wi-Fi signal and transmits it to
the formerly dead zone.
What is a hub? - ANSWER: A hub connects the router to the network, takes the data packets
from the router, and sends them to all the devices connected to the network. An example is a
USB hub.
By connecting a USB hub to your computer, data packets are able to be transferred to multiple
devices connected to your computer; each device then looks at only the traffic destined for it
and ignores the rest.
Which device is used to connect host devices within a local area network? - ANSWER: The
correct answer is a switch. The switch is the best choice for managing traffic that connects
devices locally since one would not need to route or direct traffic outside of the local area
network.
Which device operates at layer 2 of the OSI model?
- Hub
- Repeater
- Switch
- Router - ANSWER: The correct answer is a switch.
A switch operates at the data link layer (layer 2) of the network and uses physical hardware
(MAC) addresses to identify host devices.
What are some characteristics of Cat3 UTP cables? - ANSWER: Cat3 supports up to 10 Mbps
for up to 100 meters and is commonly used for phone lines today.
What are some charactersitics of Cat4 UTP cables? - ANSWER: Cat4 supports 16 Mbps for up
to 100 meters and is not commonly used today.
What are some characteristics of Cat5 UTP cables? - ANSWER: Cat5 is used in Ethernet LANs
containing two twisted pairs allowing for up to 100 Mbps up to 100 meters between the device
and the switch, hub, or router. This has been practically replaced by the Cat5e specification.
What are some characteristics of the Cat 5e UTP cables? - ANSWER: Cat5e doubles the
number of twisted pairs to four up to 1 Gbps over up to 100 meters.
What are some characteristics of the Cat6 UTP cables? - ANSWER: Cat6 is also used in
Ethernet LANs and data centers. Cat6 is made up of four tightly woven twisted pairs (more
twists per linear foot) and supports 1 Gbps for up to 100 meters or 10 Gbps for up to 55 meters.
What are some characteristics of the Cat6a UTP cables? - ANSWER: Cat6a is an improvement
of the Cat6 standard, supporting the same standards and lengths (with the ability to run 10
D315 with complete solutions 2025.
What are the two primary protocols used in networking? - ANSWER: TCP and IP
What are the four layers of the TCP/IP model in descending order? - ANSWER: 1. Application
(top)
2. Transport
3. Network
4. Network Interface (bottom)
What are the seven layers of the OSI model in ascending order? - ANSWER: 1. Physical
(bottom)
2. Data link
3. Network
4. Transport
5. Session
6. Presentation
7. Application
What are basic characteristics of the Transmission Control Protocol (TCP)? - ANSWER: TCP is
reliable in terms of delivery as it verifies the data and resends it if not delivered.
What are some characteristics of User Datagram Protocol (UDP) - ANSWER: UDP is unreliable
as it doesn't guarantee redelivery of the data?
What is a brief synopsis of the Application layer in the TCP/IP model for networks? - ANSWER:
The Application layer is responsible for the communication protocols between nodes. The
protocols in this layer include Hypertext Transfer Protocol (HTTP and HTTPS), Secure Shell
(SSH), and Network Time Protocol (NTP), among many others.
What is a brief synopsis of the Transport layer in the TCP/IP Protocol? - ANSWER: The
Transport layer is responsible for the end-to-end transport of data. The protocols that live in this
layer are the Transmission Control Protocol (TCP) and User Datagram Protocol (UDP)
,What is a brief synopsis of the Network layer in the TCP/IP Protocol? - ANSWER: The Network
layer defines the logical transmission protocols for the whole network. The main protocols that
live in this layer are the Internet Protocol (IP), Internet Control Message Protocol (ICMP), and
the Address Resolution Protocol (ARP).
What is a brief synopsis of the Network Interface Protocol? - ANSWER: The Network Interface
layer establishes how data should be physically sent through the network.
What is a quick synopsis of Layer 7 in the Open Systems Interconnection (OSI) model? -
ANSWER: The Application layer is Layer 7. It is responsible for network applications (like HTTP
or FTP) and their production of data to be transferred over the network.
What is a quick synopsis of Layer 6 in the Open Systems Interconnection (OSI) model? -
ANSWER: The Presentation layer is Layer 6. It is responsible for translating data from the
application layer into the format required to transmit the data over the network as well as
encrypting the data for security if encryption is used.
What is a quick synopsis of Layer 5 in the Open Systems Interconnection (OSI) model? -
ANSWER: The session layer is Layer 5. It is responsible for connection establishment, session
maintenance, and authentication.
What is a quick synopsis of Layer 4 in the Open Systems Interconnection (OSI) model? -
ANSWER: The Transport layer is Layer 4. It provides services to the application layer and
receives services from the network layer. It is responsible for reliable delivery of data. It
segments and reassembles data in the correct order for the receiving device. It may also handle
the reliable delivery of data and any retries of data that are lost or corrupted (for example, TCP
does this). This layer is often called the heart of the OSI.
What is a quick synopsis of Layer 3 in the Open Systems Interconnection (OSI) model? -
ANSWER: The Network Layer is Layer 3. It is responsible for the transmission of data between
hosts in different networks as well as the routing of data packets. This layer is implemented in
routers and some switches.
What is a quick synopsis of Layer 2 in the Open Systems Interconnection (OSI) model? -
ANSWER: The Data Link is layer 2. That Data Link layer is responsible for the delivery of data
to the receiving device or node. This layer is implemented in switch and bridge devices as well
as anything with a network interface, like a wireless or wired network card.
What is a quick synopsis of Layer 1 in the Open Systems Interconnection (OSI) model? -
ANSWER: The Physical is layer 1. It is responsible for the physical connections of the devices
in the network. This layer is implemented in hub, repeater, modem devices, and physical
cabling.
,Which transmission control protocol/internet protocol (TCP/IP) layer performs addressing and
routing? - ANSWER: The correct answer is The Network layer. It handles addressing and
routing to different networks.
Which layer of the OSI model does a bridge to make decisions about forwarding packets? -
ANSWER: The correct answer is the Data Link layer. It represents network communication at a
MAC-address level and forwards packers to Layer 2 devices, like a bridge.
Which layer of the OSI model establishes, manages, and terminates connections? - ANSWER:
The correct answer is the Session layer. It establishes, manages, and terminates connections.
What is a modem? - ANSWER: A modem is a device necessary for sending and receiving data.
Modems allow computers to transport digital information over analogue lines, such as phone or
cable lines. Types of modems include cable modems, DSL modems, and satellite modems.
What is a router? - ANSWER: A router is a point of connection between two or more networks
that forwards data packets between the networks. To have internet in your home, you need an
internet router that connects the networks on the internet to the network of your home.
You can access the internet's network either through a wired Ethernet port or via Wi-Fi.
What is a switch? - ANSWER: A switch is used to connect devices in a specific network and
allows them to communicate efficiently within the network. A switch is a more complex version
of a hub, in that switches have the capability to add security measures and function far more
intelligently, sending traffic directly from the sender to the receiver without other devices being
aware of the communication.
Thus, a switch is less chatty and allows for more simultaneous conversations between devices.
Most internet routers include a switch in the form of wired and wireless Ethernet connections.
What is bridge, in an IT context? - ANSWER: A bridge is similar to a router in that it connects
two or more networks. The difference is that a router analyzes data packets to determine where
to send the packet next, whereas a bridge simply forwards the data to the next network without
analysis.
This makes for fast data transfer that lacks versatility. Bridges are not widely used in modern
networks, as routers and switches are the favored devices.
What is a repeater? - ANSWER: A repeater is a device used to strengthen, replicate, and
regenerate signals that are weakened (for example, because of distance) during transmission.
In many large homes, the Wi-FI signal does not extend to the end of the house farthest from the
router.
, A range extender is a form of repeater that takes the distorted Wi-Fi signal and transmits it to
the formerly dead zone.
What is a hub? - ANSWER: A hub connects the router to the network, takes the data packets
from the router, and sends them to all the devices connected to the network. An example is a
USB hub.
By connecting a USB hub to your computer, data packets are able to be transferred to multiple
devices connected to your computer; each device then looks at only the traffic destined for it
and ignores the rest.
Which device is used to connect host devices within a local area network? - ANSWER: The
correct answer is a switch. The switch is the best choice for managing traffic that connects
devices locally since one would not need to route or direct traffic outside of the local area
network.
Which device operates at layer 2 of the OSI model?
- Hub
- Repeater
- Switch
- Router - ANSWER: The correct answer is a switch.
A switch operates at the data link layer (layer 2) of the network and uses physical hardware
(MAC) addresses to identify host devices.
What are some characteristics of Cat3 UTP cables? - ANSWER: Cat3 supports up to 10 Mbps
for up to 100 meters and is commonly used for phone lines today.
What are some charactersitics of Cat4 UTP cables? - ANSWER: Cat4 supports 16 Mbps for up
to 100 meters and is not commonly used today.
What are some characteristics of Cat5 UTP cables? - ANSWER: Cat5 is used in Ethernet LANs
containing two twisted pairs allowing for up to 100 Mbps up to 100 meters between the device
and the switch, hub, or router. This has been practically replaced by the Cat5e specification.
What are some characteristics of the Cat 5e UTP cables? - ANSWER: Cat5e doubles the
number of twisted pairs to four up to 1 Gbps over up to 100 meters.
What are some characteristics of the Cat6 UTP cables? - ANSWER: Cat6 is also used in
Ethernet LANs and data centers. Cat6 is made up of four tightly woven twisted pairs (more
twists per linear foot) and supports 1 Gbps for up to 100 meters or 10 Gbps for up to 55 meters.
What are some characteristics of the Cat6a UTP cables? - ANSWER: Cat6a is an improvement
of the Cat6 standard, supporting the same standards and lengths (with the ability to run 10
