Information Flow Across the Internet

What is the Internet? A large group of computers that link together to form the Worldwide Area Network (WAN)

What is Needed to Connect to the Internet? Device that needs to connect to the internet Computer, Laptop, Smartphone Client Application that a client uses to view a webpage Internet Explorer, Safari, Google Chrome Web Browser Distributes an internet connection to multiple devices Needed in order to connect to the internet wirelessly Router or Switch Translates analog signals into digital signals so that they can be used to provide internet access Modem A company that provides internet service to its clients Cox Communications, Century Link Internet Service Provider

OSI Model Layer 6- Presentation Layer 7- Application Layer 5-Session Layer 4- Transport Layer 3- Network Layer 2- Data Link Layer 1- Physical Includes the hardware needed to transfer information across the internet, such as wire cabling. Used to describe the process of how information travels from one device to another. Describes how data travels through the internet. Includes a Network Interface Card (NIC), which is the hardware that allows the device to connect to the internet. The NIC contains a MAC Address, which uniquely identifies each device connecting to the internet. Also creates a frame, which contains the MAC address, Source MAC address, data, and a frame check sequence. The frame makes sure that the data arrives correctly. Breaks frame into multiple pieces of information called “packets”. Then, a router or switch is used to direct packets to its desired destination using an IP (Internet Protocol) Address. The IP Address is a numerical label assigned to each device, which is used for communication. The TCP port number is added to the end of the IP Address, which completes the destination for a communication session. Ensures that the information is delivered in the correct order that they were originally sent. Manages and coordinates different sessions between applications. Translates data into an application type format. Includes the application where the data enters the destination client device, such as a web browser.

TCP/IP Model Application Layer Contains application layer protocols, such as HTTP, DNS, and DHCP Transport Layer Provides connection oriented and connectionless communications Internet Layer Deals with IP addressing and routing Link Layer Handles physical elements, such as cabling and physical addresses Demonstrates the protocol that a device should use when sending data across the internet.

How Does it Work? 1.Make a request by typing a web address into your web browser ( 2.Requested information is broken down into packets. 3.Router then directs packets to your Internet Service Provider (ISP). 4.ISP directs information to the Domain Name Server, which decodes into it’s IP Address. 5.DNS directs packets to it’s destination based on it’s IP Address. 6.Server reassembles packets into original data. 7.Server reads request and sends the requested website ( back to your computer.