INFORMATION FLOW ACROSS THE INTERNET

TYPE URL INTO SEARCHBAR HTTP Request http://www.DouglasAndCompany.com Douglas&Company KRAMER RITCHIE

Getting Destination IP Address Client Computer DNS Server HTTP Request Destination IP Address DNS Server gets Douglas&Company’s IP Address which is assigned by their Internet Service provider Douglas&Company Kramer Ritchie

Creating the Data Packet Packets are created by the client’s computer Client Computer They contain a label, source and destination IP addresses, source and destination port numbers, and many other things. …But more on that later Douglas&Company Kramer Ritchie

The OSI Model Parts are known as layers Explains computer-to-computer communication in seven parts Parts are known as layers Protocols for each layer connect to surrounding layers’ protocols Douglas&Company Kramer Ritchie

Application Layer Presentation Layer Session Layer Transport Layer Seventh Layer Communication between software and network services Presentation Layer Sixth Layer Format data for different applications and hosts Session Layer Fifth Layer Manages connection between different parts of a network(s) Transport Layer Fourth Layer Manages computer-to-computer data delivery Douglas&Company Kramer Ritchie

Network Layer Data Link Layer Physical Layer First Layer Third Layer Translate network addresses used to route data Data Link Layer Second Layer Breaks data into frames or “data packets” Physical Layer First Layer Uses packets to generate signals to send through cables and devices Douglas&Company Kramer Ritchie

Data Network Addressing Data Packets Client Computer DHCP gives client computer a unique, temporary IP address for the network HTTP protocol sends your request to the Web’s server and back at the end of the process Data is broken down into packets Douglas&Company Kramer Ritchie

What was that? This is a router Data Packets Connects devices on a network, and decides the best route for data using information stored within the packets …Now where were we? Douglas&Company Kramer Ritchie

Modems connect users to the internet using the client’s IP address Port Numbers in packets designate a specific part of an IP address’s server Data Packets TCP (Transmission Control Protocol) moves the HTTP from the clients computer to Douglas&Company’s server and back Client Modem Modems connect users to the internet using the client’s IP address Douglas&Company Kramer Ritchie

TCP/IP protocol creates a socket (specific destination) using the destination IP and destination port number Data Packets Internet Packet has reached the internet to communicate with Douglas&Company’s server Douglas&Company Kramer Ritchie

Douglas&Company’s End Data Packets Douglas and Company’s Router Douglas and Company’s Server Douglas and Company’s Modem Douglas&Company’s End Douglas&Company Kramer Ritchie

You Made It! Douglas&Company Douglas&Company’s server sends return packets using the source IP address. This is executed through the same process that got us here. The client computer uses HTTP to dislpay the packets as a web page. http://www.DouglasAndCompany.com Douglas&Company Douglas&Company Kramer Ritchie