23CS7PCNWP Network Programming Sem VII Units 1–2

The subject, actually explained.

Detailed notes for first-time study, rebuilt from Stevens, Fenner & Rudoff — UNIX Network Programming, Vol 1, not from slides. Every protocol diagram here is live, every C program steps line by line next to the state it creates, and every question from last year's paper is worked in full.

Written so that someone who has never opened a socket can follow it, and still complete enough to answer a ten-mark question from.

Figure 2.5TCP three-way handshake

Three packets, and the connection exists. Chapter 2 has this one playable, step by step, with the states on both ends.

Before the exam

Start here if you are short on time.

READ THIS FIRST The 2026 format The paper changed: 50 marks, organised by Bloom level, and Part II is twenty marks of writing code. SOLVED PAPER Internals-1, 2025 All eight questions worked in full, with the mark split for each and the diagrams the examiner is looking for. PRACTICE Probable questions What the syllabus and the slides point at but last year's paper skipped — with model answers. REVISION Cheatsheet Every diagram, every system call, every state, on one page you can print.

Unit 1 — Introduction & Sockets

Chapters 1–4

Unit 2 — TCP Client/Server & Options

Chapters 5 and 7

How to read this

The page uses a small, fixed set of blocks. Learn them once.

Every idea that is not obvious on sight carries one of these. If a paragraph lost you, look for the yellow one underneath it — that is the same thing said without the vocabulary.

The same idea again as something you already do. socket() is picking up a handset; bind() is telling people your number.

§2.6 · p.37 The book's own words, or a literal function prototype. Set in mono on sunken paper, so you always know which sentences you can quote.

The specific thing that costs marks. inet_addr cannot represent 255.255.255.255; TIME_WAIT lasts 2 MSL, not one.

Where this appeared, or is likely to. Links straight to the worked answer.

What the colours mean

Colour on this site is never decoration — it is a claim about the data, and it is the same claim on every page and in both themes.

Sky — the client side

Mint — the server side

Butter — a term being defined

Rose — an error, an RST, a trap

Lilac — SCTP

So in a diagram, a sky arrow is always something the client sent and a mint arrow is always something the server sent — no legend needed, on any figure, in any chapter.