Course Introduction
CSE312 — Web Development
The Internet
Networks, TCP/IP
Local Area Network (LAN)
Connect a small group of devices
Internet Service Provider (ISP)
Connect customers to The Internet
Tier 1 Networks
The Internet
Data Centers Power Apps
It’s all Cables!
How do we use these cables?
Internet Protocol
Internet Protocol (IP) Address
- Every device has an IP Address
- Use this address to send messages to that device
- Ex: 172.217.12.211
- Use DNS (Domain Name Server) to lookup IP address by domain name
IP address for cse312.com?
159.89.179.140
Data is sent over the Internet in packets/datagrams
Large messages are sent in multiple packets
Routing Packets
- Check the destination IP address of the packet
- Send the packet to the next router on its path
- Fuhgettaboutit
The Internet is Unreliable
Many factors cause packets to be dropped
Transmission Control Protocol
Transmission Control Protocol (TCP)
Makes the Internet reliable
- Detect and resend dropped packets
- Adds port numbers to identify specific programs
- Connect to a port number/IP address combination (TCP/IP)
- 127.0.0.1:8080
TCP 3-way Handshake
TCP/IP in CSE312
- Use libraries to do all this for us
- Assume TCP/IP works and that we have reliable communication over the Internet
- Freely send and receive messages (As bytes)
- Your code (HW) will start with HTTP
- Much deeper TCP/IP coverage, and more, in CSE489: Modern Networking Concepts!