UDP and TCP protocols

1. UNIT V
Transport Layer
&
Application Layer

2. Transport Layer
• UDP: User Datagram Protocol
• TCP: Transmission Control Protocol

3. Introduction to UDP
The UDP header.

4. TCP: Transmission Control Protocol

5. The TCP Service Model
Well Known ports.

6. The TCP Segment Header
TCP Header.

7. TCP Connection Establishment
(a) TCP connection establishment in the normal case.
6-31

8. (b) Call collision.

9. TCP Connection Release

10. TCP Connection Management Modeling
The states used in the TCP connection management finite state machine.

11. TCP Transmission Policy
Window management in TCP.

12. TCP Congestion Control
(a) A fast network feeding a low capacity receiver.

13. (b) A slow network feeding a high-capacity receiver.

14. TCP Timer Management
TCP Uses multiple timers to do works. The following are
the various types of Timers.
• Retransmission Timer
• Persistence Timer (Used to prevent Deadlocks)
• Keep Alive Timer (Connection is ideal for long Time)

15. • Retransmission Timer : The sender after sending the
data unit it will start the Retransmission Timer, if the
sender does not receive any acknowledge from the
receiver after some time Retransmission timer goes off
and the sender will retransmit the data unit once again.
• Persistence Timer : The Receiver sends an Ack with
window size of zero telling the sender to wait.
Later the receiver updates the window but the data unit
with the update is lost.
Now both sender and receiver will wait forever
resulting in a Deadlock state. To avoid this DL the
Persistence timer is set and once if the timer is gone
off the sender transmits a probe message to the
receiver.

16. • Keep Alive Timer : When a connection has been ideal
for a long time , the keep alive timer may go off to
cause one side to check if other side is still there.
If it fails to respond, the connection is Terminated.

17. The Application Layer

18. DNS – The Domain Name System

19. Name Space
i) Flat Name Space
ii) Hierarchical Name Space (Ex: Domain Name
space)
• Flat Name space searching will be difficult.
• Domain name space is a tree format having root at
the top.

21. • Each node in the tree has a domain name.
• Full Domain is a sequence of labels separated by
dots.
• The domain names are always read from leaves to
root.
• Domain names are of two types
i) Fully qualified domain names.
Ex: cse.gprec.ac.in
ii) Partially qualified domain names.
Ex: cse.gprec

22. Domain Name Space
• DNS Name space is a Hierarchical name
space.
Top Level Domain
• Ex: cse.gprec.ac.in
Most Specific Most Generic

23. The DNS Name Space
A portion of the Internet domain name space.

24. Resource Records
The principal DNS resource records types.

25. Name Servers
Part of the DNS name space showing the division into zones.

26. Thank You