[MrSecurity]

today we will be covering ,network Topologies,OSI model ,Tcp suite

Network topologies

Network topologies represent the physical side of the network, and they form part of the foundation of our overall system the first thing you need to understand is that you must consider two opposing yet related concepts

physical and logical what's that? . The physical layout
of a network relates directly to the wiring and cabling that connects devices. Some of the
common layouts we’ll cover are the bus, ring, star, mesh, and hybrid. the logical layout of the network is the methodology to access a network the things you can't see or touch it's the flow of information and data.
ok Here we go

bus: connecting all the network nodes into one run that works as the main connection for all connected devices.
bus-downside: any damage that may occur to the backbone connection could result in network connectivity lost.

ring: the connection backbone is looped into a ring layout some ring layouts use a concentric circle design to provide redundancy if one ring fails. each client or node will carry the connection and deliver the packets to it's destination
- a second ring is not required for the network to function properly.the redundant ring architecture is typically seen in installation that includes (FDDI) fiber Distributed data interface

star: A star topology attaches multiple nodes to a centralized network device that ties the network together like (hub or switch),

mesh:essentially a web of cabling that attaches a group of clients or nodes to each other it can look little messy.and it can also make troubleshooting a bear. however this setup is often used for mission-critial-services because of its high level  redundancy and resistance to outages. an example of mesh network is the internet.

hybrid:a combination of the former topologies.
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IP
The Internet Protocol (IP) is a network-layer (Layer 3) protocol that contains addressing information
and some control information that enables packets to be routed. IP is documented in RFC 791 and
is the primary network-layer protocol in the Internet protocol suite. Along with the Transmission
Control Protocol (TCP), IP represents the heart of the Internet protocols. IP has two primary
responsibilities: providing connectionless, best-effort delivery of datagrams through an
internetwork; and providing fragmentation and reassembly of datagrams to support data links with
different maximum-transmission unit (MTU) sizes.
we will be talking about this in more details in the next tutorial
Open system interconnection.


physical layer
The physical layer consists of the physical media and dumb devices like (hub) that
make up the infrastructure of our networks.

data link

The data link layer works to ensure that the data it transfers is free
of errors. At this layer, data is contained in frames. Functions such as media access control (MAC)
and link establishment occur at this layer. This layer encompasses basic protocols such as 802.3 for Ethernet and 802.11 for Wi-Fi.

network layer

network layer determine the path of data packet
at this layer we see ip addressing for routing data packets
the layer also includes routing protocols such as routing information protocol (RIP)
(IGRP) interior gateway routing protocol which has been replaced with (EIGRP) enhanced interior gateway routing protocol

transport layer
The transport layer ensures the transport or sending of data is successful. This function can include error checking operations as well as working to keep data messages in sequence. At this layer we find the Transmission Control Protocol (TCP) and the User Datagram Protocol (UDP)

session layer
The session layer identifies established system sessions between different network entities. When you access a system remotely, for example, you are creating a session between your computer and the remote system. The session layer monitors and
controls such connections, allowing multiple, separate connections to different resources.
Common use includes NetBIOS and RPC

presentation layer
The presentation layer provides a translation of data that is understandable
by the next receiving layer. Traffic flow is presented in a format that can be
consumed by the receiver and can optionally be encrypted with protocols such as Secure
Sockets Layer (SSL).

Application layer
The application layer functions as a user platform in which the user
and the software processes within the system can operate and access network resources.
Applications and software suites that we use on a daily basis are under this layer. Common
examples include protocols we interact with on a daily basis, such as FTP and HTTP.

TCP SUITE
TCP is known as a connection-oriented protocol  because it establishes a connection and
verifies that packets sent across that connection make it to their destination. The process
starts with what is called a SYN packet. This SYN packet starts the hand-shake
process by telling the receiving system that another system wants its attention (via
TCP of course). The receiving system then replies to the originating system with a SYN-
ACK response. A SYN-ACK response is an acknowledgment response to the original SYN
packet. Once the original sender receives the SYN-ACK response, it in turn responds with
an ACK packet to verify that it has received the SYN-ACK and is ready to communicate via
TCP.
the next part of this tutorial will be released shortly.

if you have any question or suggestion feel  free to do so.

[Synthx]

While I don't have time to fully read this at the moment, it looks like a VERY great tutorial! Thanks for starting to contribute to the community.

[Blink]

I quickly read through this. I'll read it more carefully later, but it was nice. Looking forward to the next one!

EDIT: Read it in full, still was nice

[Esoterith]

Seems like a high quality tutorial. Will read when I have more time.

[mothered]

From what I've read, It's very accurate and well elaborated.

Good work.

[ethics404]

Explanations are precise and to the point. The image is really helpful. Thanks a lot mate.

[phyrrus9]

I've got some more info to add on top of this. Here are 2 of my tutorials about networking (from 2015) from a programming perspective

IP header
TCP header

Tutorials are also listed on this page, please look

[MrSecurity]

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[sinn]

Nice work, good detail. Looking forward to the next one.