ELEMENTS OF TRANSPORT PROTOCOL

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