COMPTIA Network+ N10-009 Exam Questions and Correct Answers
What does the OSI model stand for and what are the seven layers?
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
Physical layer -- signaling, cabling, connections
No protocols
Examples of layer 1 issues and solutions
Fix cabling, punch-downs, etc.
Run loopback tests, test/replace cables, swap adapter cards
Loopback test
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
Describe layer 2 of the OSI model
Data Link layer, the basic network "language", the foundation of
communication
* MAC address on Ethernet
The "switching" layer
,COMPTIA Network+ N10-009 Exam Questions and Correct Answers
Describe layer 3 of the OSI model
Network layer, the "routing layer"
* Internet Protocol (IP)
* Fragments frames to traverse different networks
Describe layer 4 of the OSI model
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
Session layer, communication between devices (start, stop, restart)
* Control protocols, tunneling protocols
Describe layer 6 of the OSI model
Presentation layer
* Character encoding
* Application encryption
* Often combined with layer 7, the application layer
Describe layer 7 of the OSI model
Application layer, the layer we see
* HTTP, FTP, DNS, POP3
OSI model mapped to real-world
Layer 7 = Your eyes
Layer 6 = Application encryption (SSL/TLS)
Layer 5 = Control protocols, tunneling protocols
Layer 4 = TCP segment, UDP datagram
Layer 3 = IP Address, Router, Packet
,COMPTIA Network+ N10-009 Exam Questions and Correct Answers
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
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
- 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
- Forwards traffic based on data link address
- May provide PoE (Power over Ethernet)
Multilayer switch
includes layer 3 (routing) functionality
Application-specific integrated circuit (ASIC)
Type of processor designed to perform a specific function, such as
switching.
, COMPTIA Network+ N10-009 Exam Questions and Correct Answers
Firewall
- 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?
Often in the ingress/egress
What is the difference between a traditional firewall and NGFW? (new
generation firewall)
A NGFW can manage applications
What is the difference between an IDS (Intrusion Detection System) and an
IPS (Intrusion Prevention system)?
An IDS is worse because it can only detect and alert for traffic while IPS
can alert and stop the malicious traffic
Intrusions
Exploits against operating systems, applications, etc
* Examples: buffer overflows, cross-site scripting, etc.
Load Balancer
Hardware or software that balances the load between two or more servers.
What does the OSI model stand for and what are the seven layers?
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
Physical layer -- signaling, cabling, connections
No protocols
Examples of layer 1 issues and solutions
Fix cabling, punch-downs, etc.
Run loopback tests, test/replace cables, swap adapter cards
Loopback test
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
Describe layer 2 of the OSI model
Data Link layer, the basic network "language", the foundation of
communication
* MAC address on Ethernet
The "switching" layer
,COMPTIA Network+ N10-009 Exam Questions and Correct Answers
Describe layer 3 of the OSI model
Network layer, the "routing layer"
* Internet Protocol (IP)
* Fragments frames to traverse different networks
Describe layer 4 of the OSI model
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
Session layer, communication between devices (start, stop, restart)
* Control protocols, tunneling protocols
Describe layer 6 of the OSI model
Presentation layer
* Character encoding
* Application encryption
* Often combined with layer 7, the application layer
Describe layer 7 of the OSI model
Application layer, the layer we see
* HTTP, FTP, DNS, POP3
OSI model mapped to real-world
Layer 7 = Your eyes
Layer 6 = Application encryption (SSL/TLS)
Layer 5 = Control protocols, tunneling protocols
Layer 4 = TCP segment, UDP datagram
Layer 3 = IP Address, Router, Packet
,COMPTIA Network+ N10-009 Exam Questions and Correct Answers
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
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
- 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
- Forwards traffic based on data link address
- May provide PoE (Power over Ethernet)
Multilayer switch
includes layer 3 (routing) functionality
Application-specific integrated circuit (ASIC)
Type of processor designed to perform a specific function, such as
switching.
, COMPTIA Network+ N10-009 Exam Questions and Correct Answers
Firewall
- 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?
Often in the ingress/egress
What is the difference between a traditional firewall and NGFW? (new
generation firewall)
A NGFW can manage applications
What is the difference between an IDS (Intrusion Detection System) and an
IPS (Intrusion Prevention system)?
An IDS is worse because it can only detect and alert for traffic while IPS
can alert and stop the malicious traffic
Intrusions
Exploits against operating systems, applications, etc
* Examples: buffer overflows, cross-site scripting, etc.
Load Balancer
Hardware or software that balances the load between two or more servers.
