Computer Networking

Part of the Interview Prep Roadmap. Coverage ratings are explained there.

The OSI/TCP-IP stack as the foundation, then TCP vs. UDP, DNS, HTTP, and picking the right protocol for a scenario.

Coverage: rich

Resources · Computer Networks — Cloudflare Learning · High Performance Browser Networking — free online book

Network Models

• OSI model layers
• TCP/IP model
• Encapsulation across layers

Practice

• The seven OSI layers — DSI, with answer
• Application layer vs. transport layer — IUBAT
• Multiplexing and demultiplexing — IUBAT

Transport Layer

• TCP: connection setup, reliability, ordering, flow control
• UDP: connectionless delivery and trade-offs
• Ports and sockets
• Choosing TCP vs. UDP for a workload

Practice

• TCP vs. UDP — Exabyting, with answer
• Compare TCP and UDP — Therap
• Differences between TCP and UDP — REVE Systems
• Which TCP/UDP statement is true — Brain Station 23
• Protocol for video streaming — Brain Station 23
• Ports, and common service ports — Therap
• Java socket programming — REVE Systems

Network Layer & Addressing

• IPv4 and IPv6 addressing
• Public vs. private IP ranges
• Subnetting and CIDR
• Routing basics
• NAT

Practice

• What an IP address is and why it is needed — Therap
• CIDR, gateway and NAT — Therap
• IPv4 vs. IPv6 — IUBAT
• Logical vs. physical addressing — IUBAT
• Subnet a /24 network — Green University
• Network ID and broadcast from a mask — Sonargaon University
• Which address is private — Brain Station 23
• Can a device hold several IPs — Therap, with answer

Application Layer Protocols

• HTTP and HTTPS
• DNS resolution
• SMTP and FTP
• WebSockets

Practice

• What happens when you type a URL and hit enter — Exabyting, with answer
• HTTP vs. HTTPS — Therap
• How HTTPS transfers data — Exabyting, with answer
• Is HTTPS stateful or stateless — Exabyting, with answer
• What DNS is — National University
• Which protocol resolves an address to an IP — Brain Station 23
• Protocol for sending mail with attachments — Brain Station 23
• ping, traceroute and nslookup — Therap

Security & Performance

• TLS and certificates
• Firewalls and proxies
• Latency, bandwidth, and throughput

Practice

• What a firewall is — Therap
• What a VPN is — National University
• Traffic shaping and QoS — World University
• Can ping 8.8.8.8 but not google.com — Therap
• Packet loss appears only on the internet link — Therap