OSI vs TCP/IP comparison in Computer Networks - Visual Side-by-Side Comparison

Concept Flow - OSI vs TCP/IP comparison

Start: Data to send

↓

OSI Model Layers

↓

App

↓

TCP/IP Model Layers

↓

App

↓

Data sent over network

Data moves down OSI's 7 layers or TCP/IP's 4 layers before sending over the network.

Execution Sample

Computer Networks

OSI Layers: Application -> Presentation -> Session -> Transport -> Network -> Data Link -> Physical
TCP/IP Layers: Application -> Transport -> Internet -> Link

Shows the order of layers in OSI and TCP/IP models for sending data.

Analysis Table

Step	Model	Layer	Role	Action	Data Format
1	OSI	Application	User interface	Prepare data	Data
2	OSI	Presentation	Data format	Translate/Encrypt	Formatted Data
3	OSI	Session	Manage sessions	Establish session	Session Data
4	OSI	Transport	Reliable delivery	Segment data	Segments
5	OSI	Network	Routing	Add IP address	Packets
6	OSI	Data Link	Physical addressing	Add MAC address	Frames
7	OSI	Physical	Transmit bits	Send bits	Bits
8	TCP/IP	Application	User interface + format	Prepare & format data	Data
9	TCP/IP	Transport	Reliable delivery	Segment data	Segments
10	TCP/IP	Internet	Routing	Add IP address	Packets
11	TCP/IP	Link	Physical addressing + transmission	Add MAC + send bits	Frames
12	End	-	-	-	Data sent over network

💡 Data fully processed by all layers and sent over the network

State Tracker

Layer	Data Format Start	After OSI Layer 2	After OSI Layer 4	After OSI Layer 6	After OSI Layer 7	After TCP/IP Layer 2	After TCP/IP Layer 4
Data	Raw Data	Formatted Data	Segments	Frames	Bits	Segments	Frames

Key Insights - 3 Insights

Why does OSI have more layers than TCP/IP?

OSI separates functions like presentation and session for clarity (see execution_table steps 2 and 3), while TCP/IP combines these in the Application layer (step 8).

Is the Physical layer present in TCP/IP?

TCP/IP combines Physical and Data Link into the Link layer (step 11), unlike OSI which separates them (steps 6 and 7).

Do both models handle routing the same way?

Both use a Network/Internet layer for routing (OSI step 5, TCP/IP step 10), adding IP addresses to packets.

Visual Quiz - 3 Questions

According to the execution_table, which OSI layer adds the MAC address?

A Physical

B Network

C Data Link

D Session

💡 Hint

Look at execution_table row 6 where MAC address is added.

In TCP/IP, which layer combines physical transmission and data link functions?

A Link

B Internet

C Transport

D Application

💡 Hint

Check execution_table row 11 describing combined MAC and bit sending.

At which OSI layer does data become 'Segments' according to variable_tracker?

A After Layer 2 (Presentation)

B After Layer 4 (Transport)

C After Layer 6 (Data Link)

D After Layer 7 (Physical)

💡 Hint

See variable_tracker column 'After OSI Layer 4' for data format.

Concept Snapshot

OSI model has 7 layers: Application, Presentation, Session, Transport, Network, Data Link, Physical.
TCP/IP model has 4 layers: Application, Transport, Internet, Link.
OSI separates functions more finely; TCP/IP combines some layers.
Both models prepare data step-by-step before sending over network.
Understanding layer roles helps in networking and troubleshooting.

Full Transcript

This visual execution compares OSI and TCP/IP network models. Data starts at the Application layer and moves down through layers adding information or changing format. OSI has 7 layers, each with a specific role, while TCP/IP has 4 layers combining some OSI functions. The execution table shows each step where data is prepared, segmented, addressed, and finally sent as bits. Variable tracking shows how data changes format at key layers. Key moments clarify common confusions about layer differences and functions. The quiz tests understanding of which layers do what in each model. This helps beginners see how data flows through network layers in both models.

Practice

1. Which of the following correctly states the number of layers in the OSI and TCP/IP models?

easy

A. OSI has 7 layers; TCP/IP has 4 layers

B. OSI has 4 layers; TCP/IP has 7 layers

C. Both OSI and TCP/IP have 5 layers

D. OSI has 5 layers; TCP/IP has 6 layers

Solution

1. Step 1: Recall OSI model layers

   The OSI model is known to have 7 distinct layers: Physical, Data Link, Network, Transport, Session, Presentation, and Application.

2. Step 2: Recall TCP/IP model layers

   The TCP/IP model has 4 layers: Network Interface, Internet, Transport, and Application.

3. Final Answer:

   OSI has 7 layers; TCP/IP has 4 layers -> Option A

4. Quick Check:

   OSI = 7 layers, TCP/IP = 4 layers [OK]

Hint: Remember OSI 7 layers, TCP/IP 4 layers [OK]

Common Mistakes:

• Confusing the number of layers between OSI and TCP/IP
• Thinking both models have the same number of layers
• Mixing up layer names with layer counts

2. Which layer in the OSI model corresponds to the Application layer in the TCP/IP model?

easy

A. Physical layer

B. Session layer

C. Application layer

D. Network layer

Solution

1. Step 1: Identify OSI layers related to application functions

   In OSI, the Application, Presentation, and Session layers handle application-level tasks.

2. Step 2: Match TCP/IP Application layer

   The TCP/IP Application layer combines OSI's Application, Presentation, and Session layers into one.

3. Final Answer:

   Application layer -> Option C

4. Quick Check:

   OSI Application = TCP/IP Application [OK]

Hint: TCP/IP Application = OSI Application + Presentation + Session [OK]

Common Mistakes:

• Choosing Session or Network layer instead of Application
• Confusing Physical layer with Application layer
• Not knowing TCP/IP layers combine OSI layers

3. Consider this statement: "The TCP/IP model's Internet layer is equivalent to which OSI layer?" What is the correct answer?

medium

A. Transport layer

B. Session layer

C. Data Link layer

D. Network layer

Solution

1. Step 1: Understand TCP/IP Internet layer role

   The Internet layer in TCP/IP handles routing and addressing of packets across networks.

2. Step 2: Match with OSI layer

   The OSI Network layer performs similar functions like routing and logical addressing.

3. Final Answer:

   Network layer -> Option D

4. Quick Check:

   TCP/IP Internet = OSI Network [OK]

Hint: Internet layer matches OSI Network layer [OK]

Common Mistakes:

• Confusing Transport with Network layer
• Choosing Data Link instead of Network layer
• Mixing Session layer with Internet layer

4. A student claims: "The OSI model is mainly used for practical internet communication, while TCP/IP is mostly theoretical." Identify the error.

medium

A. Both models are only theoretical and not used practically

B. The OSI model is theoretical; TCP/IP is practical and used on the internet

C. TCP/IP is theoretical; OSI is practical and used on the internet

D. Both models are practical and used equally on the internet

Solution

1. Step 1: Understand OSI model purpose

   OSI is a conceptual framework mainly used for teaching and understanding networking.

2. Step 2: Understand TCP/IP model purpose

   TCP/IP is the practical protocol suite used for real internet communication.

3. Final Answer:

   The OSI model is theoretical; TCP/IP is practical and used on the internet -> Option B

4. Quick Check:

   OSI = theory, TCP/IP = practical [OK]

Hint: OSI is theory; TCP/IP runs the internet [OK]

Common Mistakes:

• Thinking OSI is used practically on the internet
• Believing TCP/IP is only theoretical
• Assuming both models have equal practical use

5. You want to explain why TCP/IP combines several OSI layers into one. Which reason best applies?

hard

A. TCP/IP was designed for simplicity and practical use, merging related functions

B. TCP/IP has fewer layers because it ignores some networking functions

C. OSI layers are combined in TCP/IP to increase complexity for security

D. TCP/IP layers are fewer because it only supports wired networks

Solution

1. Step 1: Analyze TCP/IP design goals

   TCP/IP was created to be practical and efficient for real-world internet communication.

2. Step 2: Understand layer merging rationale

   It merges OSI's Application, Presentation, and Session layers into one Application layer to simplify the model.

3. Step 3: Eliminate incorrect reasons

   TCP/IP does not ignore functions, nor increase complexity for security, nor limit to wired networks.

4. Final Answer:

   TCP/IP was designed for simplicity and practical use, merging related functions -> Option A

5. Quick Check:

   Simplicity and practicality explain TCP/IP layers [OK]

Hint: TCP/IP merges layers for practical simplicity [OK]

Common Mistakes:

• Thinking TCP/IP ignores networking functions
• Believing TCP/IP is more complex than OSI
• Assuming TCP/IP only supports wired networks