5 TCP IP Model ITS

TCP/IP Protocol Suite
(Internet Model)

Comparison of Network Models
1. OSI Model (Open System Interconnect)
2. Internet Model (TCP/IP Model)

TCP/IP
Model

Application
5. Application Layer

Presentation

ISO
Model

Session
4. Transport Layer
3. Network Layer

Transport
Network

2. Host-to-Network

Data Link

1. Physical Layer

Physical

1

Comparison of Network Models
TCP/IP is ussed in the Internet. Common mechanism that is gaining on/surpassing the OSI Model.

Data Flow in TCP/IP Network

Some books show 4 layers and others 5 in TCP/IP. We will consider 5

2

Internet Model (TCP/IP Model) user’s access to the network end-to-end issues,, manage logicall connection 5. Application Layer

routing and address

4. Transport Layer network access. moving a message from one computer to the next computer in the network path

3. Network Layer

2. Host-to-Network pphysical connection between the sender and tthe receiver

1. Physical Layer

Internet Model
What application data to deliver?

Emails, Web pages

How to deliver the data logically ?

Destination address, the route to get there, etc?

How to transport the data physically?

Transmission media

5. Application Layer

4. Transport Layer
3. Network Layer

2. Host-to-Network
1. Physical Layer

3

TCP/IP and the OSI Model

TCP/IP Protocol Layering
Each layer takes data from above
• adds header information to create new data unit
• passes new data unit to layer below source M
Ht M
Hn Ht M
Hl Hn Ht M

application transport network link physical

destination application transport network link physical M
Ht M
Hn Ht M
Hl Hn Ht M

message segment datagram

frame

4

The term “Message" is usually associated with
Application layer
The term "Segments" is usually associated with
Transport layer
The term "Packets/Datagrams" associated with Network Layer and

is

usually

The term "Frames" is usually associated with Data
Link Layer

TCP/IP Encapsulation Between Layers

5

Message Flow Through Layers: Encapsulation
User Data