JS 171 Study Guide


What is the internet?

What is a network?

Local networks

What is a router?

What is a protocol?

OSI Model: Organized by layer function

Internet Protocol Suite Model: Organized by communication scope




What happens in the physical layer?

What is Bandwidth?

What is Latency?

Link/Data Link

Ethernet Protocol. How does it operate?

Ethernet Frames

MAC Addressing


What does IP do?

What’s an IP Address?

How do messages get lost at this level?


What is multiplexing?

What’s a port number?

What is the difference between a connectionless and a connection-oriented system?


What is TCP?

What is UDP?

Similarities and Differences

What are some things that can go wrong in the transport layer?


What’s the difference between internet and web?

DNS — How does it work?

Client-server model — How does it work?

URLs (aka Uniform Resource Locators)

Components of a URL


Scheme vs Protocol

How to construct a valid URL

URL encoding

HTTP and the Request/Response Cycle

What is the HTTP request response cycle?

What are HTTP requests?

Request types

What are HTTP responses?

Status Codes

“State” on the web

Server-side vs client-side frameworks

What’s up with servers?


What are some security risks affecting HTTP?

What are some measures to mitigate against security risks?

What services does TLS provide?

How does TLS provide encryption?

TLS Handshakes


Message Authentication Code (MAC)

Evolution of HTTP

HTTP has evolved to adapt to a changing internet ecosystem.

What can browser APIs provide?

What networking paradigms exist beyond client server?

What is the main limiter of networked application performance and how can I deal with it?



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