My future job and responsibilities

Session Layer: Software layers ^Is responsible for establishment of connection, authentication and security between the devices.

Transport Layer: Heart of OSN model. End to end delivery of the complete message.

Network Layer: Transmission of data from one host to the other if both of the devices are located at different networks.

Data Link Layer: With the data link layer is responsible for node to node delivery of messages in physical layer.

Physical Layer Hardware layers ^: responsible for actual physical connection between devices. It carries information in bit format. It has certain functions. It has certain functions such as bit synchronization, bit rate control.

Firewall functions

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  accept information: Allows traffic.
  
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  reject information: rejects traffic with a report.
  
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  gateways: rejects traffic without giving a message.
  

IP (Internet protocol)

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  Public IP: Dynamic. Changes every time you connect to the internet.
  
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  Private IP: Static.
  
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  ipv4: Previously established internet protocol. First version of ip. It uses 32 bit address scheme which means it has 4 billion addresses. Only has numbers.
  
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  ipv6: latest version of ip which is more secure because it uses 128 bit address Scheme. Has Hexadecimal values.
  
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  DNS: domain name.
  

TCP/IP architectures

TCP

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  Stands for: Transmission Control Protocol
  
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  Synchronization: follows it and therefore is good for chatting.
  
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  Used at server and client end.
  
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  Layer 1: Application and presentation are merged together
  
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  Layer 2: Session Layer:
  
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  Layer 3: Transport layer network layer and data link layer are merged together
  
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