- The Internet
- Large sprawling network on a global scale.
- A very large sprawling Wide Area Network
- A network of many networks
A little History…
- 1960’s
- Advance Researh Projects Agency (ARPAnet) is a system of linked mainframes
- Developed by military to ensure communication in times of crisis
- 1980’s
- MILNET splits from ARPAnet to form the Internet (INTERconnected NETwork)
- Access was limited to military and scientists
- As the Personal Computer (PC) increased in popularity, so did the demand for the access to info stored on computers linked to the internet
ISP
- Internet Service Provider
- Most networks lease a connection to the internet from an ISP
- The ISP in turns typically leases a connection to a larger ISP and continues until the backbone is established
- How Information is sent
- Data traffic is controlled by routers which examine information packets to determine where data is to be sent
- Data packets will travel through many different routers to reach destination
- For example:
- Clark wants to send a message via a telephone line to Bruce who uses a cable modem.
- The packet is sent from Clark to his ISP
- The ISP examines the packet and forwards the message to its larger ISP through a T1 high speed cable line
- The larger ISP sends the message to the closest access point on the backbone
- The back bone send the message to the access point closet to its destination
- From there, the message travels to another ISP then to the cable company, and finally to Bruce’s cable modem
File Sharing Protocols
- In order to transmit data over the internet, a number of protocols have been developed
- Protocols provide a level of standardization so different computers can understand
TCP – Transmission Control Protocol
- Responsible for breaking data into packets and reassembling them at the other end
- TCP on sender’s end communicates with TCP at receiver’s end
- IP – Internet Protocol
- Responsible for getting packets to the correct address
- Finding efficient pathways
