Client Server Architecture

This topic covers how web applications are structured and scaled. You study the request/response model, statelessness and how sessions are maintained, the three-tier separation of concerns, and infrastructure like load balancers and CDNs.

Relation 1 —

Write this relation with symbols exactly as in Deitel Web Dev — Standard reference before substituting numbers. Examiners award partial marks for a correct setup even when arithmetic slips.

Relation 2 —

Write this relation with symbols exactly as in Deitel Web Dev — Standard reference before substituting numbers. Examiners award partial marks for a correct setup even when arithmetic slips.

Relation 3 —

Write this relation with symbols exactly as in Deitel Web Dev — Standard reference before substituting numbers. Examiners award partial marks for a correct setup even when arithmetic slips.

The web is built on a stateless request/response model: the server treats each HTTP request independently, so continuity (a logged-in session) must be carried explicitly in a cookie or token. Separating an application into presentation, application-logic and data tiers lets each scale and evolve independently — the classic three-tier design. Because HTTP is stateless, servers can be made identical and interchangeable, so a load balancer can distribute traffic across many backends for capacity and fault tolerance. A CDN pushes static content to edge servers near users, cutting latency and offloading origin servers, while WebSockets add a persistent channel when the request/response pattern is too limiting for real-time updates.

State assumptions explicitly before using any relation for client server architecture — steady state, uniform properties, linear elastic material, ideal gas, incompressible flow, etc., as applicable.

Wrong assumptions invalidate the entire solution even when the formula is correct. In Web Technologies viva and GATE descriptive questions, listing valid assumptions often earns separate marks.

1. Read the question and list given data with SI units (common in Web Technologies papers).
2. Draw a neat labelled diagram where applicable — examiners in Indian universities award diagram marks even when arithmetic slips.
3. Identify which relation from this topic applies to client server architecture.
4. Use equation 1: .
5. Use equation 2: .
6. Substitute values, compute, and verify units and sign (direction).
7. State conclusion in one line — e.g. safe/unsafe, stable/unstable, feasible/infeasible.

Client Server Architecture appears in web apps and REST APIs. In Indian it software curricula this topic is tested because it connects theory to front-end and back-end web stack.

GATE and semester exams often combine client server architecture with earlier units — revise prerequisites before attempting mixed problems.

Industry interview panels sometimes ask: "Where did you use client server architecture?" — answer with a lab, mini-project, or plant visit example if possible.

Students assume HTTP maintains state on its own (it does not — sessions need cookies/tokens), confuse the tiers with physical machines, and think a load balancer requires sticky sessions in all cases. Overlooking that statelessness is what enables horizontal scaling is a conceptual gap.

Before attempting client server architecture problems, confirm you can:

1. Thin client keeps logic on the server; thick client on the browser
2. A load balancer spreads requests across backends
3. A CDN caches static assets at edge locations

Revise the solved examples in Deitel Web Dev — Standard reference and one previous-year GATE or university paper for this unit.