TCP/IP has 4 layers instead of OSI's 7 layers, but indirectly includes 5 layers. The layers are application, transmission, network, and host-to-network. While TCP/IP and OSI have similar functionality, TCP/IP includes sub-protocols like TCP, UDP, and SCTP to transmit data more efficiently between layers. Protocols like ARP, RARP, ICMP, and IGMP operate at the network layer and help devices resolve addresses, control messages, and send messages to multiple devices.

2. TCP/IP- Transmission control Protocol
- Internet Protocol

3. INTRODUCTION
Based on the OSI model, TCP/IP has been developed.
There is no difference between TCP/IP & OSI except in
structure or design.
OSI has 7 layers but TCP/IP has only 4 layers.
In TCP/IP indirectly it has 5 layers, directly it has 4
layers.
Main difference between OSI & TCP/IP is, in TCP it
contains sub protocols to transmit the data more
efficiently

4. MODEL
Application
Transmission
Network
Datalink layer
Physical layer
SMTP FTP Telnet ARPANET
TCP UDP SCTP
ICMP IGMP RARP ARP

5. All the functionalities of 7 layers are same as in OSI
reference model.
Here both physical & datalink layer is combined as 1
layer called “host-to-network” layer.
Network layer is same as in OSI, here we have some
sub protocols to transfer the data more efficiently.

6. NETWORK LAYER

7. ARP: Address Resolution Protocol
When we are sending our data to a particular
destination, sender needs IP & MAC address of
destination.
If sender doesn’t have the IP address of destination
then it uses the “ARP” protocol & broadcasts or
resolves the data in a network.
So that each device receives the data & checks the
MAC address of the data if it is matching with the
device MAC address then it receives otherwise it
deletes the data.

8. RARP: Reverse Address Resolution Protocol
When we are sending our data to a particular
destination in a network, sender needs IP & MAC
address of destination & it needs self IP & MAC also.
If at all it dosen’t have self IP address then it uses
RARP protocol & identifies its IP address in routing
table by matching its MAC address.
After detecting the IP address it sends the data to the
destination.

9. ICMP: Internet Control Message Protocol
By using ICMP protocol we can control the messages
in online.

10. IGMP: Internet Group Message Protocol
By using this protocol source can send message to no.
of devices at a time.

11. TRANSMISSION LAYER

12. In transmission layer, we have TCP, UDP, SCTP
protocols.
TCP is connection oriented, we use this in reliable
communication.
UDP is a User Datagram Protocol. It is a
connectionless protocol. We use this in unreliable
communication.
SCTP is a Stream Control Transmission Protocol. This
is the combination of both TCP & UDP protocols.

13. APPLICATION LAYER

14. In Application layer we use SMTP, FTP, TELNET,
ARPANET for interfaces to transfer the data efficiently.