COMPTIA NETWORK+ N10-009 EXAM
2025 QUESTIONS AND ANSWERS
What does the OSI model stand for and what are the seven layers? - ANS Open Systems
Interconnection Reference Model
Layer 7 = Application
Layer 6 = Presentation
Layer 5 = Session
Layer 4 = Transport
Layer 3 = Network
Layer 2 = Data Link
Layer 1 = Physical
Describe layer 1 of the OSI model - ANS Physical layer -- signaling, cabling, connections
No protocols
Examples of layer 1 issues and solutions - ANS Fix cabling, punch-downs, etc.
Run loopback tests, test/replace cables, swap adapter cards
Loopback test - ANS A diagnostic procedure that verifies the integrity of a communication
pathway by sending a signal from a device and returning it to the same device
1 @COPYRIGHT THEBRIGHT 2025/2026
,Describe layer 2 of the OSI model - ANS Data Link layer, the basic network "language", the
foundation of communication
* MAC address on Ethernet
The "switching" layer
Describe layer 3 of the OSI model - ANS Network layer, the "routing layer"
* Internet Protocol (IP)
* Fragments frames to traverse different networks
Describe layer 4 of the OSI model - ANS Transport layer, the "post office" layer, parcels and
lettings from one side of the network to the other
* TCP & UDP
Describe layer 5 of the OSI model - ANS Session layer, communication between devices
(start, stop, restart)
* Control protocols, tunneling protocols
Describe layer 6 of the OSI model - ANS Presentation layer
* Character encoding
* Application encryption
* Often combined with layer 7, the application layer
Describe layer 7 of the OSI model - ANS Application layer, the layer we see
* HTTP, FTP, DNS, POP3
OSI model mapped to real-world - ANS Layer 7 = Your eyes
Layer 6 = Application encryption (SSL/TLS)
Layer 5 = Control protocols, tunneling protocols
2 @COPYRIGHT THEBRIGHT 2025/2026
,Layer 4 = TCP segment, UDP datagram
Layer 3 = IP Address, Router, Packet
Layer 2 = Frame, MAC address, Extended Unique Identifier (EUI-48, EUI-64), Switch
Layer 1 = Cables, fiber, and the signal itself
Real-world example of the OSI model - ANS Application: https://mail.google.com
Presentation: SSL encryption
Session: Link the presentation to the transport
Transport: TCP encapsulation
Network: IP encapsulation
Data Link: Ethernet
Physical: Electrical signals
Router - ANS - Routes traffic between IP subnets
- OSI layer 3 devices
- Routers inside of switches sometimes called "layer 3 switches"
- Often connects diverse network types
* LAN, WAN, copper, fiber
Switch - ANS - Forwards traffic based on data link address
- May provide PoE (Power over Ethernet)
Multilayer switch - ANS includes layer 3 (routing) functionality
Application-specific integrated circuit (ASIC) - ANS Type of processor designed to perform a
specific function, such as switching.
3 @COPYRIGHT THEBRIGHT 2025/2026
, Firewall - ANS - Filters traffic by port number or application
- Encrypts traffic, VPN between sites
- Most firewalls can be layer 3 devices (routers)
* Network Address Translation (NAT)
* Dynamic routing
Where does a firewall sit on the network? - ANS Often in the ingress/egress
What is the difference between a traditional firewall and NGFW? (new generation firewall) -
ANS A NGFW can manage applications
What is the difference between an IDS (Intrusion Detection System) and an IPS (Intrusion
Prevention system)? - ANS An IDS is worse because it can only detect and alert for traffic
while IPS can alert and stop the malicious traffic
Intrusions - ANS Exploits against operating systems, applications, etc
* Examples: buffer overflows, cross-site scripting, etc.
Load Balancer - ANS Hardware or software that balances the load between two or more
servers.
TCP offloading - ANS a technique that moves some TCP functions from software to
hardware, which reduces the CPU's workload and frees up resources for other tasks
SSL offload - ANS A device that can provide encryption/decryption capabilities instead of the
servers themselves
Content switching - ANS Application-centric balancing, a method where all requests for a
web page would go only to that server for faster speeds
4 @COPYRIGHT THEBRIGHT 2025/2026
2025 QUESTIONS AND ANSWERS
What does the OSI model stand for and what are the seven layers? - ANS Open Systems
Interconnection Reference Model
Layer 7 = Application
Layer 6 = Presentation
Layer 5 = Session
Layer 4 = Transport
Layer 3 = Network
Layer 2 = Data Link
Layer 1 = Physical
Describe layer 1 of the OSI model - ANS Physical layer -- signaling, cabling, connections
No protocols
Examples of layer 1 issues and solutions - ANS Fix cabling, punch-downs, etc.
Run loopback tests, test/replace cables, swap adapter cards
Loopback test - ANS A diagnostic procedure that verifies the integrity of a communication
pathway by sending a signal from a device and returning it to the same device
1 @COPYRIGHT THEBRIGHT 2025/2026
,Describe layer 2 of the OSI model - ANS Data Link layer, the basic network "language", the
foundation of communication
* MAC address on Ethernet
The "switching" layer
Describe layer 3 of the OSI model - ANS Network layer, the "routing layer"
* Internet Protocol (IP)
* Fragments frames to traverse different networks
Describe layer 4 of the OSI model - ANS Transport layer, the "post office" layer, parcels and
lettings from one side of the network to the other
* TCP & UDP
Describe layer 5 of the OSI model - ANS Session layer, communication between devices
(start, stop, restart)
* Control protocols, tunneling protocols
Describe layer 6 of the OSI model - ANS Presentation layer
* Character encoding
* Application encryption
* Often combined with layer 7, the application layer
Describe layer 7 of the OSI model - ANS Application layer, the layer we see
* HTTP, FTP, DNS, POP3
OSI model mapped to real-world - ANS Layer 7 = Your eyes
Layer 6 = Application encryption (SSL/TLS)
Layer 5 = Control protocols, tunneling protocols
2 @COPYRIGHT THEBRIGHT 2025/2026
,Layer 4 = TCP segment, UDP datagram
Layer 3 = IP Address, Router, Packet
Layer 2 = Frame, MAC address, Extended Unique Identifier (EUI-48, EUI-64), Switch
Layer 1 = Cables, fiber, and the signal itself
Real-world example of the OSI model - ANS Application: https://mail.google.com
Presentation: SSL encryption
Session: Link the presentation to the transport
Transport: TCP encapsulation
Network: IP encapsulation
Data Link: Ethernet
Physical: Electrical signals
Router - ANS - Routes traffic between IP subnets
- OSI layer 3 devices
- Routers inside of switches sometimes called "layer 3 switches"
- Often connects diverse network types
* LAN, WAN, copper, fiber
Switch - ANS - Forwards traffic based on data link address
- May provide PoE (Power over Ethernet)
Multilayer switch - ANS includes layer 3 (routing) functionality
Application-specific integrated circuit (ASIC) - ANS Type of processor designed to perform a
specific function, such as switching.
3 @COPYRIGHT THEBRIGHT 2025/2026
, Firewall - ANS - Filters traffic by port number or application
- Encrypts traffic, VPN between sites
- Most firewalls can be layer 3 devices (routers)
* Network Address Translation (NAT)
* Dynamic routing
Where does a firewall sit on the network? - ANS Often in the ingress/egress
What is the difference between a traditional firewall and NGFW? (new generation firewall) -
ANS A NGFW can manage applications
What is the difference between an IDS (Intrusion Detection System) and an IPS (Intrusion
Prevention system)? - ANS An IDS is worse because it can only detect and alert for traffic
while IPS can alert and stop the malicious traffic
Intrusions - ANS Exploits against operating systems, applications, etc
* Examples: buffer overflows, cross-site scripting, etc.
Load Balancer - ANS Hardware or software that balances the load between two or more
servers.
TCP offloading - ANS a technique that moves some TCP functions from software to
hardware, which reduces the CPU's workload and frees up resources for other tasks
SSL offload - ANS A device that can provide encryption/decryption capabilities instead of the
servers themselves
Content switching - ANS Application-centric balancing, a method where all requests for a
web page would go only to that server for faster speeds
4 @COPYRIGHT THEBRIGHT 2025/2026
