NT 1210 Lab 3.1.1, 3.2.1, 3.3.1
The Purpose of Reference Models
Exercise 3.1.1
What would happen if wireless devices were not governed by the Wi-Fi Alliance and each vendor had its own standards and protocols? What impact would this have on your personal life or business communications?
The process of marketing the wireless devices would be much slower than if the Wi-Fi Alliance wasn’t governing them. This would impact my personal life or business communications in a big way. The reason is Wi-Fi Alliance certifies the products through pre-standard rules thus insuring the speed of product market and quality.

The OSI Reference Model
Exercise 3.2.1
Define each layer of the OSI Model and state what each layer provides.
Physical – transmission and reception of the unstructured raw bit stream over a physical medium. Carries signals for higher layers and describes the electrical /optical , mechanical and functional interfaces.
Data link – Error free transfer of data frames from node to node over the physical layer , allowing the higher layers to assume virtually error –free transmission over the link.
Network - is the third layer, which controls the subnet operation by deciding which physical path data should take based on network conditions and priority of service with other factors.
Transport - is the fourth layer, which ensures the error-free delivery of messages in sequence and with no losses or duplications. Higher layer protocols are relieved from concerns with data transfer between them and their peers.
Session - which allows session establishment between application processes running processes running on different stations. Maintenance , termination, or session establishment consist of what is called the session.
Presentation - is the sixth layer, which provides the formatted data to be presented to the application layer. It may also translate data from a format being used by the application layer into a common format at the sending station. Afterwards, it translates the common format to a format known to the application layer at the receiving station.
Application - is the seventh layer, which provides the access of network services by serving as a window for users and application processes. They layer contains functions such as, resource sharing, device redirecting, remote file access, remote printer access, inter-process communication, network management, directory services, electronic messaging and network virtual terminals.
The TCP/IP Network Model
Exercise 3.2.1
Create a mapping between the TCP/IP model and OSI reference model.
TCP/IP
Application Layer…………………………………………Application layer
Presentation layer
Session layer ↓
Transport layer…………………………………………….Transport layer
Network layer……………………………………………..Network layer
Data link layer……………………………………………..Data link layer
Physical layer………………………………………………Physical layer

The biggest differences between the two are in the top layer, with the TCIP/IP model defining many functions as part of the application layer, while the OSI model split those functions into multiple layers.