1. INFORMATION FLOW ACROSS THE INTERNET

2. TYPE URL INTO SEARCHBAR
HTTP Request
Douglas&Company
KRAMER RITCHIE

3. 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

4. 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

5. 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

6. 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

7. 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

8. 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

9. 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

10. 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

11. 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

12. 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

13. 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.
Douglas&Company
Douglas&Company
Kramer Ritchie