Layer 1 - Physical:
Receives the frames and data and sends them via the local media (copper wires, fiber-optic cables, etc.)
to the switches, routers, etc., along the network path.
Layer 2 - Data link:
- Receives the packets and adds physical addressing by adding sender and receiver MAC addresses to
each data packet.
- This information forms a unit called a frame.
Layer 3 - Network:
The routing layer (IP addresses, routers, packets).
Layer 4 - Transport:
The functions defined in this layer provide for the reliable transmission of data segments, as well as
the disassembly and assembly of the data before and after transmission.
,Layer 5 - Session:
- Establishes, manages, and terminates sessions between two communicating hosts.
- Synchronizes dialog between the presentation layers of the two hosts and manages their data
exchange.
Layer 6 - Presentation:
- Ensures that info sent at application layer of one system is readable by the application layer of
another system.
- May translate between multiple data formats by using a common format.
Layer 7 - Application:
- Closest to the user.
- Provides network services to the applications of the user, such as email, file transfer, and terminal
emulation.
,Router:
A device that forwards data packets between computer networks.
Switch:
A computer networking device that connects network segments.
Firewall:
A part of a computer system or network that is designed to block unauthorized access while
permitting outward communication.
Intrusion detection system (IDS):
Monitors network traffic to identify possible malicious activity and log information about it.
Intrusion prevention system (IPS):
Sits behind the firewall and uses anomaly detection or signature-based detection to identify and
respond to network threats.
Load Balancer:
Hardware or software that balances the load between two or more servers.
, Proxy:
A system or router that provides a gateway between users and the internet.
Network-attached storage (NAS):
A server that is placed on a network with the sole purpose of providing storage to users, computers,
and devices attached to the network.
Storage area network (SAN):
A high-speed network with the sole purpose of providing storage to other attached servers.
Wireless Access point (AP):
A device that enables wireless systems to communicate with each other, provided that they are on the
same network.
Wireless Controller:
A central management console for all of the APs on a network.
Content delivery network (CDN):
Receives the frames and data and sends them via the local media (copper wires, fiber-optic cables, etc.)
to the switches, routers, etc., along the network path.
Layer 2 - Data link:
- Receives the packets and adds physical addressing by adding sender and receiver MAC addresses to
each data packet.
- This information forms a unit called a frame.
Layer 3 - Network:
The routing layer (IP addresses, routers, packets).
Layer 4 - Transport:
The functions defined in this layer provide for the reliable transmission of data segments, as well as
the disassembly and assembly of the data before and after transmission.
,Layer 5 - Session:
- Establishes, manages, and terminates sessions between two communicating hosts.
- Synchronizes dialog between the presentation layers of the two hosts and manages their data
exchange.
Layer 6 - Presentation:
- Ensures that info sent at application layer of one system is readable by the application layer of
another system.
- May translate between multiple data formats by using a common format.
Layer 7 - Application:
- Closest to the user.
- Provides network services to the applications of the user, such as email, file transfer, and terminal
emulation.
,Router:
A device that forwards data packets between computer networks.
Switch:
A computer networking device that connects network segments.
Firewall:
A part of a computer system or network that is designed to block unauthorized access while
permitting outward communication.
Intrusion detection system (IDS):
Monitors network traffic to identify possible malicious activity and log information about it.
Intrusion prevention system (IPS):
Sits behind the firewall and uses anomaly detection or signature-based detection to identify and
respond to network threats.
Load Balancer:
Hardware or software that balances the load between two or more servers.
, Proxy:
A system or router that provides a gateway between users and the internet.
Network-attached storage (NAS):
A server that is placed on a network with the sole purpose of providing storage to users, computers,
and devices attached to the network.
Storage area network (SAN):
A high-speed network with the sole purpose of providing storage to other attached servers.
Wireless Access point (AP):
A device that enables wireless systems to communicate with each other, provided that they are on the
same network.
Wireless Controller:
A central management console for all of the APs on a network.
Content delivery network (CDN):
