• Protocols and models
Protocols and models

Protocols and models


 

PROTOCOLS INTRODUCTION

In this post I will be discussing about protocols and how they operate on different levels within different types of devices, a protocol is a type of rule that certain devices must follow. The different types of protocols are endless but each one has its own use and purpose for different tasks that may need to be performed. Each protocol was created with a use in mind, this even includes computer networking

OSI LAYERS

The OSI is a list of different sections that contain protocols which are used for different ways of communicating between different devices. Each layer contains different protocols for the many different tasks they may encounter, for example within the transport section there will be a number of protocols stored so that the protocol can be changed depending on the situation.

  1. PHYSICAL: this layer will be used to communicate with hardware such as keyboards that are used for typing , this layer converts the physical action the user has performed and will convert it to binary so that the machine can identify the action performed
  2. DATA LINK: this layer of OSI manages the DATA and information through different wires and hardware, its responsible for getting the information physically from one place to another, an example of this could be a router, a router is used to send and receive DATA through a wireless signal or wired so that the machine can connect to either the internet or a network.

 

  1. NETWORKING: this layer is used to allow the OSI to communicate to other machines and networks to allow file sharing; it does this by allowing the different nodes to communicate even if there different types of devices, this layer is important because without it a computer may not be able to communicate with other systems.

 

  1. TRANSPORT: the transport layer is used to transport different information between computers and networks , this is similar to the networking layer however , the transport layer works out which way is the best to transport that device between different devices, it is also used to send errors and detect issues , if this occurs it will try to re-send the data.

 

  1. SESSION: the session layer manages the different connections that machines have. It does this by establishing, terminating and sometimes restarting procedures, all these are required for a session to work correctly.

 

  1. PRESENTATION: the presentation layer is used to package data in a way that the information can be understood by cross platforms (other devices); this is not used as often as it used to anymore, but was still useful when it was required, and it is no longer used because most devices are already compatible.

 

  1. APPLICATION: the application layer is used to interact with the software and programs like a user, this is used on all programs that require communication between devices, this is because it reads what the software wants to communicate to.

Bluetooth: Bluetooth is used over short areas which can vary from 10m – 100m, this all depends on the type of class the Bluetooth is in, and for example mobile devices are class 2 meaning 10m on average. Bluetooth is useful because it can send the signal through walls, and also allow connections between devices with little effort; this can be found in almost all mobile devices as well as speakers etc.

WIFI: Wi-Fi is based on Bluetooth however it gives an improvement; WIFI has 7 standards which all have different features, such as speed etc. WIFI is mainly used to give a wireless internet connection that can be received by anything with a WIFI receiver; most modern phones come with this as well as laptops. However because of WIFI’s features, it requires 5 time the amount of power than Bluetooth.

protocol Frequency signal Max data rate
Legacy 802.11 2.4GHz FHSS or DSSS 2mbps
802.11a 5GHz OFDM 54mbps
802.11b 2.4GHz HR-DSSS 11mbps
802.11g 2.4GHz OFDM 54mbps
802.11n 2.4 or 5GHz OFDM 600mbps(theoretical)

 

WIRELESS SECURITY PROTOCOLS: these types of protocols are set in place to protect a wireless network from being connected to without permission; this is because if a network has a wide area in range, people may connect to it if it remains unprotected.

CELLULAR RADIO: mobile devices all contain this feature, this is because for the device to be able to give out and receive signals it needs to act like a radio that relay the messages, these messages are relayed between different cells that are in different locations, each cell can be a maximum of 5 miles away before the signal starts to fade.

GSM (2G): this type of communications uses different digital signals to communicate with other devices, because of this it has been set as the standard for all mobile devices to have.

UMTS (3G): this type of communication allows more data to be transferred at higher speeds compared to 2G, by this it allows broadband to be used on the go as well as streaming music, videos and much more. However this is just an extension of GSM.

TCP/IP Model

Application
 Transport
Internet
Network interface

 

TCP/IP (internet protocol suite) is very similar to the OSI as they both do a similar job; in fact the TCP/IP model is based on the OSI model. The reason they are different is because the creators so the TCP/IP model thought there was too many layers in the OSI model, so in the TCP/IP model they shortened the layers into 4 layers, they did this by taking the OSI layers and putting them into 4 different categories’ based on their job.

TCP transmission control protocol

The TCP’s main job is to detect any errors that may occur during files being sent and received; it does this by performing a number of different tests. One of the tests it preforms is a checksum.  A checksum checks the binary code that is being received to see if has the same amount of data as when it left the other machine.

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