What you need to know: (In progress)

 

TCP/IP Application Layer

• protocols provide services to the application software running on a computer.

 

• The application layer does not define the application itself, but it defines services that application needs.

 

• Example of application layer protocol, Hypertext Transfer Protocol (HTTP)
  • Defines how web browsers can pull the contents of a web page from a web server.

TCP/IP Transport Layer

•  Transport layer protocols provide services to the application layer protocols that reside one layer higher in the TCP/IP model.

 

•  The two most commonly used transport layer protocols are the Transmission Control Protocol (TCP) and the User Datagram Protocol (UDP).

 

TCP/IP Network Layer

•  The TCP/IP network layer includes a small number of protocols, but only one major protocol: the Internet Protocol (IP).

 

• IP provides several features, most importantly, addressing and routing.

 

 TCP/IP Link Layer (Data Link Plus Physical)

• The TCP/IP model’s original link layer defines the protocols and hardware required to deliver data across some physical network.

 

• The term link refers to the physical connections, or links, between two devices and the protocols used to control those links.

 

•  The link layer includes all the variations of Ethernet protocols, along with several other LAN standards

 

• The link layer includes wide-area network (WAN) standards for different physical media, which differ significantly compared to LAN standards because of the longer distances involved in transmitting the data.

 

• Examples of Link/Data link layer protocols
  • Ethernet
  • PPP (Point to Point Protocol)