Internet 101 Flashcards
Understand the fundamentals of how the internet works and its relevancy to backend software development
Fundamental definition of the internet
Interconnected computers that follow protocols to ensure smooth data transfer; a network of networks
Who/Why/When for building the Internet?
Department of Defense in the 1960s as a distributed communications network that could withstand a nuclear war
IP
Internet Protocol - concerned with data origin and destination
TCP
Transmission Control Protocol - preserves the data on the journey from origin to destination
HTTP
Hyper Text transfer protocol - moving data between the client (web browser) and server (website)
Packet
The smallest unit of data is transferred across networks; contains meta data on the IP addresses and re-assembly directions
Router
Tells packets where to go
IP Address
Unique identifier for a device within a network, typically a series of 4 numbers separated by periods
Domain Name
Human-readable identifier for a website
Domain Name Server
Translates domain name to an IP address
SSL
Secure Sockets Layer - security standard for packet transmission
TLS
Transport Layer Security - security standard for packet transmission
UDP
User Datagram Protocol, reliable and efficient packet transmission on the journey - similar to TCP
HTTPS
Leverages the SSL/TLS protocols for data transfer
Ports
Application or service ID’s that are accessible on target IP server
Socket
A combination of IP and port number creating a unique endpoint for the client to request
Connections
Two sockets that agree to communicate; negotiates the segment size and window size
Connections - Segmentation
The sender breaks down data into segments (or packets) that fit within the network’s MTU (Maximum Transmission Unit) to avoid fragmentation. These segments must also adhere to the receiver’s window size, which dictates the maximum number of segments that can be sent without waiting for acknowledgment from the receiver.
Connections - Window Size
The maximum number of packets (aka segments); each less than the network’s MTU (Maximum Transmission Unit), that the receiver will accept without granting permission/giving acknowledgment.
Security - SSL/TLS Certificates
Secure Socket Layer and Transport Layer Security Certificates are essentially ID’s granted to both server and client from a Certificate Authority to prove they are talking to the right, trusted machines
Security - Handshake
Client and Server negotiate encryption and security standards for further communications
Latency
Time required for data to travel point to point (aka ping time). Sometimes referred to as RTT (round trip time). Influential factors: physical distance, routing (path), and network traffic
Bandwidth
Max amount of data that travels through your network per second; metaphor # of lanes on a highway, # of cars you can fit in a single instant
Internet Speed
How fast data moves to/from your device; influenced by the bandwidth and latency
