Computer Network Models

ECE 422 - Data Communication & Computer Networks. Understand how data flows, encapsulates, and travels across a computer network.

Start Learning Launch Lab

The OSI Model

Click on a layer to explore its functions, protocols, and data units (PDUs). The OSI model standardizes communication functions.

7. Application

Data

6. Presentation

Data

5. Session

Data

4. Transport

Segment

3. Network

Packet

2. Data Link

Frame

1. Physical

Bits

Select a layer from the stack to view details

The TCP/IP Model

Practical Implementation

While OSI is a theoretical reference, TCP/IP is the practical standard used by the internet. It combines the OSI layers into 4 robust layers.

4
Application
OSI Layers 5, 6, 7 (HTTP, FTP, DNS)
3
Transport
OSI Layer 4 (TCP, UDP)
2
Internet
OSI Layer 3 (IP, ICMP)
1
Network Access
OSI Layers 1, 2 (Ethernet, Wi-Fi)

Key Differences

  • Reliability: TCP/IP assumes unreliable networks (best effort), whereas OSI originally assumed reliability.
  • Approach: OSI is a "generic" model (protocol independent), while TCP/IP is based on standard protocols.
  • Layers: TCP/IP merges Presentation and Session into the Application layer.

Data Encapsulation Lab

Visualize how data is wrapped (encapsulated) as it moves down the OSI stack.

Current Status

Ready to transmit...

Legend

Data (L7)
Segment (L4)
Packet (L3)
Frame (L2)
Bits (L1)
L7 Application
L6 Presentation
L5 Session
L4 Transport
L3 Network
L2 Data Link
L1 Physical
DATA
TRANSMISSION MEDIUM (CABLE/WIFI)