Computer Networks for Placements: The Questions That Keep Coming Back
By the Codveri team ·
OSI and TCP/IP layers, TCP versus UDP, DNS, HTTP and HTTPS, IP addressing and what happens when you type a URL.
The layers
Learn the OSI model (physical, data link, network, transport, session, presentation, application) and the four-layer TCP/IP model. For each layer know one protocol: IP at the network layer, TCP and UDP at the transport layer, HTTP and DNS at the application layer.
TCP versus UDP
TCP is connection-oriented, ordered and reliable, using a three-way handshake and retransmission. UDP is connectionless and faster with no delivery guarantee. Web pages and email use TCP; video calls and games often use UDP.
What happens when you type a URL
This question tests many topics. The browser asks DNS for the IP address, opens a TCP connection (and a TLS handshake for HTTPS), sends an HTTP request, the server replies, and the browser renders the page. Practise telling it in two minutes.
HTTP and HTTPS
Know the methods (GET, POST, PUT, DELETE), common status codes (200, 301, 404, 500) and that HTTPS is HTTP over TLS, which encrypts traffic and verifies the server.
IP addressing
IPv4 addresses are 32 bits; IPv6 are 128 bits. Understand subnet masks, private address ranges and why NAT lets many devices share one public address.
Practise
Use MCQs for quick recall, then explain each topic aloud. Take a timed CS Fundamentals test on Codveri when you feel ready.