THIS DESCRIBES VARIOUS ELEMENTS OF TRANSPORT PROTOCOL IN TRANSPORT LAYER OF COMPUTER NETWORKS THERE ARE SIX ELEMENTS OF TRANSPORT PROTOCOL NAMELY 1. ADDRESSING 2. CONNECTION ESTABLISHMENT 3.CONNECTION REFUSE 4.FLOW CONTROL AND BUFFERS 5.MULTIPLEXING 6.CRASH RECOVERY

1. ELEMENTS OF
TRANSPORT
PROTOCOL
A PRESENTATION BY
SHASHANK, ABHISHEK AND UDIT

2. TRANSPORT LAYER
• To provide reliable, cost effective data transfer from
source to destination
• This layer deals with end to end transfer of data
• Here transport entity deals with other host’s transport
entity.
• Transport layers deals with processes running on the host.

3. Elements of Transport
Protocol
• Addressing
• Connection Establishment
• Connection Release
• Flow Control and Buffering
• Multiplexing
• Crash Recovery

4. Subnet
HOST1 HOST2
Router
Process Process
END TO END TRANSMISSION OF PACKET FROM SOURCE TO DESTINATION

5. Addressing
• Application Process is connected to the TSAP
• Entity connects to the NSAP.
• There are multiple processes running within the host.

6. Application Layer
Network Layer
Transport Layer
Data Link Layer
Physical Layer
TSAP 1208
NSAP
APPLICATION PROCESS
TSAP 1582
TSAP 1969
NSAP
HOST 1 HOST 2
To access a specific service , we have to mention a specific Port Address.
SAP - Service Access Point
TSAP- Transport SAP
NSAP - Network SAP

7. Connection Establishment
USER
TSAP S1
HOST 1 HOST 2
TRANSPORT
LAYER
S2

8. USER
TSAP
process server
HOST 1 HOST 2
TIME-OF DAY
SERVER
TRANSPORT
LAYER

9. USER
TSAP
name server
HOST 1 HOST 2
TIME-OF DAY
SERVER
TRANSPORT
LAYER

10. Connection is being established by 3 way handshake
Connection Request
Acknowledgment
Data
HOST 1 HOST 2

11. Connection Request
Acknowledgment
Data
HOST 1 HOST 2

12. CONNECTION
RELEASE
• Disconnection connection between two users.
• Asymmetric Release
• Symmetric Release

13. ASYMMETRIC RELEASE
Connection Request
Acknowledgment
Data
HOST 1 HOST 2
DROP

14. SYMMETRIC RELEASE
DROP REQUEST
SEND
ACKNOWLEDGEMENT
HOST 1 HOST 2
DROP
REQUEST
SEND DATA REQ
+
START TIMER SEND DATA REQ
+
START TIMER
RELEASE
RELEASE

15. SYMMETRIC RELEASE
DROP REQUEST
SEND ACK
HOST 1 HOST 2
DROP
REQUEST
SEND DATA REQ
+
START TIMER SEND DATA REQ
+
START TIMER
RELEASE
RELEASE
TIMER
TIMOUT

16. SYMMETRIC RELEASE
DROP REQUEST
HOST 1 HOST 2
DROP
REQUEST
SEND DATA REQ
+
START TIMER SEND DATA REQ
+
START TIMER
RELEASE
TIMER
TIMOUT
DROP
REQUEST
RELEASE
TIMER
TIMOUT

17. FLOW CONTROL
• To control buffer, Transport Layer manages buffer.
VARIABLE
LENGTH
BUFFER
FIXED
LENGTH
BUFFER
CIRCULAR
BUFFER
UNUSED SPACE
IS WASTED

18. MULTIPLEXING
• UPWARD
• DOWNWARD

19. TRANSPORT
LAYER
NETWORK
LAYER
APPLICATION
LAYER
UPWARD MULTIPLEXING DOWNWARD MULTIPLEXING

20. CRASH RECOVERY
• Always Retransmit
• First Acknowledgment then write
• Retransmit in S0(Sent 2 messages, Ack of both received).
No outstanding Packet is present
• retransmit in S1(Sent 2 messages, Ack of only 1
received). Here Outstanding Packet is present
STRATEGY USED BY SENDING HOST