Computer Networks · topic
DNS name hierarchy, iterative and recursive resolution with message counts, resource record types, caching with TTLs and transport (UDP and TCP on port 53); HTTP methods and status codes, persistent and non-persistent connections, RTT counting with and without pipelining, cookies and web caching with conditional GET.
com; IP needs addresses. The Domain Name System maps between them, and also tells mail systems where to deliver mail and gives aliases. It is a distributed, hierarchical database: no server holds all names. The namespace is a tree.
The HyperText Transfer Protocol carries the Web. A client (browser) sends a request naming a resource and a method; the server sends back a response with a status code, header fields and usually a body.1 runs over TCP, by default on port 80 (443 for HTTPS, HTTP over TLS).
One-page visual sheets for this topic, in the sheet library on the store. Previews are free; the full sheets come with the subject pack.
