09 - Networking, Protocols and Real-Time Communication

<aside> 💡 Generated by BigBrain. Repeated material was merged while distinct trade-offs, caveats, examples, and operational details were retained.

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09 - Networking, Protocols and Real-Time Communication

Overview

This reference page explores the foundational concepts, mechanisms, and trade-offs in networking, protocols, and real-time communication. Topics include DNS, HTTP/HTTP/2, gRPC, serialization formats, polling mechanisms, WebSockets, network tools, and communication-level trade-offs. The material is organized from fundamentals to design choices and operational concerns.

DNS: Domain Name System

DNS is the "telephone directory" of the internet, mapping human-readable domain names to IP addresses. It eliminates the need for users to remember numerical IP addresses. DNS resolution involves multiple server types and caching mechanisms.

DNS Resolution Process

Client Request: A user enters a domain (e.g., example.com) in a browser.
Recursive Resolver: The browser queries a recursive DNS resolver (e.g., ISP's DNS server). If cached, the resolver returns the record.
Root Nameserver: If not cached, the resolver queries a root nameserver, which returns the TLD (e.g., .com) nameserver.
TLD Nameserver: The TLD nameserver provides the authoritative nameserver for the domain.
Authoritative Nameserver: The authoritative nameserver returns the DNS record (e.g., A record for IPv4).
Final Step: The client uses the IP address to connect to the server hosting the website.

DNS Server Types

Recursive Resolver: Finds the IP address by querying other DNS servers.
Root Nameserver: The first step in resolving hostnames to IP addresses. There are 13 root IP addresses, each backed by multiple servers using Anycast.
TLD Nameserver: Manages domain extensions (e.g., .com, .org).
Authoritative Nameserver: Stores DNS records for specific domains.