6. • Network Layer: This layer is responsible for the transmission of data between hosts in different
networks as well as routing of data packets. This layer is implemented through the use of devices
such as routers and some switches.
• Data Link Layer: This layer is responsible for the error-free delivery of data to the receiving device or
node. This layer is implemented through the use of devices such as switches and bridge devices as
well as anything with a network interface, like wireless or wired network cards.
• Physical Layer: This layer is responsible for the physical connections of the devices in the network.
This layer is implemented through the use of devices such as hubs, repeaters, modem devices, and
physical cabling.
■ The OSI model is widely used throughout networking documentation and discussions. Layers are
often referred to by number, not name, so memorizing the numbers and having a good
understanding of each layer’s uses are essential for success in the IT community.
7. OSI Model
The OSI (Open System Interconnection) model consists of
a seven-layer architecture that organizes the sending
of data from hosts across a network.
The OSI model was developed by the International
Standards Organization (ISO) after the TCP/IP model
to provide greater granularity of networking
assignments within the model.
8. Let's compare these two models, see how they work, and why you might choose one over the other from a
conceptual framework.
9. We'll start at the lowest layer and work our way up to the higher layers. So, in the TCP/IP model,
we begin at the bottom with the network interface layer.
This would be the physical cabling, the wireless spectrum in the case of wireless.
This would be your actual network cards.
10.
11.
12.
13.
14.
15.
16. 1. Application Layer: This layer is responsible for network applications (like HTTP or FTP) and their
production of data to be transferred over the network.
2. Presentation Layer: This layer 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.
3. Session Layer: This layer is responsible for connection establishment, session maintenance, and
authentication.
4. Transport Layer: This layer provides services to the application layer and receives services from the
network layer. It is responsible for the reliable delivery of data. It segments and reassembles data
in the correct order for it to be sent to 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 OSI.
5. Network Layer: This layer is responsible for the transmission of data between hosts in different
networks as well as routing of data packets. This layer is implemented through the use of devices
such as routers and some switches.
6. Data Link Layer: This layer is responsible for the error-free delivery of data to the receiving device
or node. This layer is implemented through the use of devices such as switches and bridge devices
as well as anything with a network interface, like wireless or wired network cards.
7. Physical Layer: This layer is responsible for the physical connections of the devices in the network.
This layer is implemented through the use of devices such as hubs, repeaters, modem devices,
and physical cabling.
17.
18. TCP/IP Model
TCP/IP model shades of blue
boxes with text, application,
transport, network, network
interface
TCP/IP stands for Transmission
Control Protocol/Internet
Protocol and is a set of protocols
used to connect network devices
to each other.
The TCP/IP networking model is
made up of four layers:
19. 1. Application Layer: This 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.
2. Transport Layer: This layer is responsible for the end-to-end transport of data. The protocols
that live in this layer are Transmission Control Protocol (TCP) and User Datagram Protocol
(UDP).
3. Network Layer: This layer defines the logical transmission protocols for the whole network.
The main protocols that live in this layer are Internet Protocol (IP), Internet Control Message
Protocol (ICMP), and Address Resolution Protocol (ARP).
4. Network Interface Layer: This layer establishes how data should be physically sent through
the network.
➢ The TCP/IP model is used for practical application when locating specific protocol. It covers
the same topics that will be found in the OSI model but in fewer layers.
20. Which Transmission Control Protocol/Internet Protocol (TCP/IP) layer performs addressing and routing?
Transport
Application
Presentation
Network (The Network layer handles addressing and routing to different networks.)
Which layer of the OSI Model does a bridge use to make decisions about forwarding data packets?
Physical
Data Link (The data link layer (layer 2) represents network communication at a MAC-address level and forwards packets on layer 2 devices, like a bridge)
Network
Transport
Which layer of the OSI model establishes, manages, and terminates connections?
Presentation
Session (The session layer establishes, manages, and terminates connections)
Network
Application
