what Is Networking and ISO-OSI Model

what Is Networking: 

Networking is the exchange of data between one or more systems that are interconnected to each other. Or in other words the exchange of information or services among individuals, groups or institutions.
                  



Before the coming of iso-osi model exchange of data is done only two same companies.. In 1984 international standard organization developed an architecture of seven layers known as OSI (open system interconnection) it is also known as reference model as discussed below:
Fig(a)layers of iso-osi reference model.

     
 Mandatory functions of osi layer:
i)Error Control.
ii)Flow control.
iii)access control.
iv)Multiplexing and de-multiplexing.
v)addressing.
layers of iso-osi model:
1)Application layer:it is the top most layer of the osi reference model.this layer serves as a window for the application services to access the network and for displaying the received information to the user.example browsers,Skype messenger etc.
2)Presentation Layer:the data from application layer is extracted here and manipulated as per the required format to transmit over the network.also this layer contains the extensions.
3)Session Layer:this layer is responsible for establishment of connection,maintenance of session,authentication and also ensures security.
4)Transport Layer:transport layer provides services to application layer and takes services from network layer.the data in the transport layer is referred to as segements.it is responsible for the end to end delivery of the complete message.the transport layer also provides the acknowledgement of the successful data transmission and re-transmits the data if an error is found.in this layer two main protocols are used ( TCP AND UDP).
5)Network layer:this layer works for the transmission of data from one host to the other located in different networks. The sender and receiver’s ip address are placed in the header by the network layer.
6)Data Link Layer:the data link layer is responsible for the node to node delivery of the message.it is the responsibility of DLL to transmit it to the host using its mac address.Data Link Layer is divided into two sub layers: 1)logical link control(LLC) and 2)Media Access Control(MAC).
7) Physical Layer: this layer is responsible for the actual physical connection between the devices.the physical Layer contains information in the form of bits.(0 and 1)

Comments

Post a Comment

Popular posts from this blog

Virtual Private Network - VPN

Image
VPN  stands for   Virtual Private Network. It is a technology that creates a safe and encrypted tunnel over a less secure network, such as the public internet. A VPN allows you to securely access a private network and share data remotely. In simple terms, a Virtual Private Network gives you online privacy and anonymity by creating a private network from a public internet connection. It hides your Internet Protocol (IP) address, making your online actions virtually untraceable.
Read more

Windows Registry Forensics: Detecting Malware Persistence with Process Monitor

Image
In the world of cybercrime investigation, the Windows Registry isn't just a database—it’s a digital diary . The Registry keeps track of nearly everything that occurs on a computer, including user behavior and system configurations . Two methods become essential for an investigator when a system is suspected of being infected: Boot Time Logging and Registry Analysis . In this guide, we will explore how to use Process Monitor (ProcMon) to look inside a Windows system and find malicious activity that may be hidden.
Read more

Mastering Incident Response: Complete Guide to CrowdResponse Forensic Tool

Image
When a security incident occurs, time is critical. Responders must collect volatile evidence —running processes, network connections, registry data—before it is lost or altered. However, installing complex forensic software on a compromised system can be slow and may contaminate evidence. CrowdResponse  offers a practical solution. Developed by CrowdStrike and available as a free,  CrowdResponse tool is  a  lightweight, portable tool allows incident responders to gather key system artifacts quickly without installation. It runs directly from a USB drive or local directory, making it ideal for live triage investigations on Windows systems. In this article, we will learn how to deploy CrowdResponse on Windows systems, master all 16 modules with practical examples, and analyze collected data to identify security threats.
Read more