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Layers of OSI Model

What does “OSI” stand for?

OSI Stands for Open Systems InterConnection. It is a model that explains the process of data transfer between Computers

List the 7 layers of the OSI model and what each one is responsible for.

1. Physical layer- physical connection between devices
2. Date Link Layer (DLL) - node to node- error free gaurantee between one node to another
3. Network Layer - sends packets from one host to another on a separate network
4. Transport Layer - handles end to end delivery of the complete packet/message/data. breaks down packet into segments, and reassembles at end delivery
5. Session Layer - Security layer, handles certificates, authentications, and establishment of a connection
6. Presentation Layer - the packet becomes translateable to the end user, for examplet, ciphering encrypted text, or formating code to be translateable on different system.
7. Application Layer - This layer exists on both the sender and end receiver, to produce and dispay the data tha in step 6 was translated to function with the step 7: application layer.

Distinguish which layers are the “hardware layers”, and which layers are the “software layers”. What does that even mean?

Layers 1-3 are the hardware layers, 4 can be both hardware and software, 5-7 is software layers. Meaning 1-3 is configured by a device that is used, for example starts with a cable connection, or satellite, etc, then uses layer 2- a switch connected to layer 3 - a router - to then layer 4 that can have a hardware piece offering a firewall, and also a software offering a firewall. To then layer 5- which is not a physical hardware piece, but a program programmed to open up the gateway/roadway for packets to be sent and received, that also authenticates through a program that was programmed to do just that, to then layer 6- that formats the packets/data into different readable puzzles that interact with the puzzle board, like .jpeg .gif.doc. txt, etc. To layer 7 that is the application that can read these puzzles pieces and show you the complete puzzle.

How can the OSI model be used in troubleshooting?

When Troubleshooting, you must first run checks on the obvious, like is the computer plugged in and has power, which would be layer 1, and working your way up the layers to save time from overlooking something so simple.

What Is Wireshark and How Is It Used?

WireShark is a program ran on the internet that can tap into the traffic between networks and computers. Feel free to stop at “How to Use Wireshark”

What is Wireshark?

a go-to network packet capture tool used by IT Professionals.

What is a packet?

A packet is the data, or what's behind the curtain of whatever you are sending on the internet etc. (it looks like code)

What 3 high-level things does Wireshark accomplish? How could these be used for nefarious purposes? For benevolent purposes?

1. Packet Capture - Someone cannot tap into what is being sent to and from you in real-time
2. Filtering - a person with mal intent can become faster at their objective by using filters instead of sifting through endless amounts of packets and data.
3. Visualization - A person with nefarious intent can after applying filters to the packets that are the target, can look into them and see entire network streams. But it can't do everything, like decypher encrypted packets, or tell if an IP address is spoofed or not.

Videos

Understanding the OSI Model Data Communication Packet, routers, and reliability