OSI Model (Open Systems Interconnection Model)
🔹 7 Layers of OSI (Top → Bottom)
Application (Layer 7) – Interface for user applications (HTTP, FTP, SMTP, DNS)
Presentation (Layer 6) – Encryption, decryption, compression
Session (Layer 5) – Session establishment & termination
Transport (Layer 4) – End-to-end delivery, flow control (TCP/UDP)
Network (Layer 3) – Logical addressing & routing (IP, Router)
Data Link (Layer 2) – MAC addressing, framing, error detection
Physical (Layer 1) – Transmission of raw bits, signals, cables
👉 Total Layers = 7
🎯 Why OSI Model is Important for Odisha Exams
For exams like:
OSSSC RI / ARI
Junior Teacher (JTS)
OSSC CGL 2026
Computer Awareness section almost always includes:
OSI layer order
Device-layer mapping (Router, Switch, Hub)
Protocol-layer mapping (TCP, UDP, HTTP, DNS, ARP)
Encryption & Presentation layer questions
IP vs MAC address layer differences
From PYQ trends, 1–3 questions regularly come from:
Number of layers
Which layer handles encryption?
Router works at which layer?
MAC address belongs to which layer?
End-to-end delivery layer
These are direct, scoring questions.
📊 Why It Is High-Scoring Topic
✔ Concept-based (no lengthy theory)
✔ Frequently repeated in OSSSC & OSSC exams
✔ Easy to memorize with layer sequence trick
✔ Helps in Networking + Internet questions
🧠Quick Memory Trick
A P (Andhra Pradesh) S T (schedule tribe) New D P (display picture)
👉 All People Seem To Need Data Processing
Application
Presentation
Session
Transport
Network
Data Link
Physical
📌 Exam Strategy for OSSSC / OSSC CGL 2026
Memorize all 7 layers in order
Learn 5–6 important protocols & their layers
Understand device-layer mapping
Practice at least 50 MCQs (high repeat rate topic)
0 Comments