The document discusses the transport layer of network fundamentals, focusing on its purpose of facilitating end-to-end communication and data preparation for transport. It outlines key concepts such as port assignments, data segmentation, and protocols like TCP (connection-oriented) and UDP (connectionless), highlighting their reliance, flow control, and error checks. Additionally, it covers essential mechanisms like three-way handshakes, segment reassembly, and congestion control.

1. Network Fundamentals – Transport Layer
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Ahmed Hamed Attia Kotb Hussein Teaching Assistant CS Department
By
Ahmed Hamed Attia Kotb
ahmed_hamed@ci.suez.edu.eg
+201227253795
Transport Layer (Layer 4)
Chapter 4

2. Agenda
• Purpose of Transport layer
• Controlling the conversation
• Data requirements
• Transport Layer protocols
– TCP
– UDP
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Ahmed Hamed Attia Kotb Hussein Teaching Assistant CS Department
Network Fundamentals – Transport Layer

3. Purpose of Transport layer
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Ahmed Hamed Attia Kotb Hussein Teaching Assistant CS Department
• Prepare Application
data to be transported
across network.
• End to End
communication
Network Fundamentals – Transport Layer

4. Purpose of Transport layer
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Ahmed Hamed Attia Kotb Hussein Teaching Assistant CS Department
• Assign Port number
• Enables multiple applications to communicate over
the network
• netstat
Network Fundamentals – Transport Layer

5. Purpose of Transport layer
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• Segmentation and
Assembling of the
data.
Network Fundamentals – Transport Layer

6. Purpose of Transport layer
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• If required, all data received reliable.
• Error Check.
Network Fundamentals – Transport Layer

7. Controlling the conversation
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Network Fundamentals – Transport Layer

8. Data requirements
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Sensitive Not Sensitive
Segments must arrive in
very specific order
Accepts out of order
No loss Tolerate some loss
Delay Sensitive to delay
Overhead No overhead
Network Fundamentals – Transport Layer

9. Transport Layer Protocols
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Ahmed Hamed Attia Kotb Hussein Teaching Assistant CS Department
TCP UDP
Connection oriented Connection less
Overhead Low overhead
Reliable delivery Best effort
Flow control (window
size)
-
20 bytes 8 bytes
Web browser
E-mail
File transfer
DNS
VoIP
Network Fundamentals – Transport Layer

10. TCP
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Network Fundamentals – Transport Layer

11. TCP – Three way handshake
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Network Fundamentals – Transport Layer

12. TCP – Four way handshake
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Network Fundamentals – Transport Layer

13. TCP – Segment Reassembly
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Network Fundamentals – Transport Layer

14. TCP – Retransmission
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Ahmed Hamed Attia Kotb Hussein Teaching Assistant CS Department
Network Fundamentals – Transport Layer

15. TCP – Congestion control
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Ahmed Hamed Attia Kotb Hussein Teaching Assistant CS Department
Network Fundamentals – Transport Layer

16. UDP
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Ahmed Hamed Attia Kotb Hussein Teaching Assistant CS Department
Network Fundamentals – Transport Layer

17. UDP– Reassembly
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Ahmed Hamed Attia Kotb Hussein Teaching Assistant CS Department
Network Fundamentals – Transport Layer

18. Thank you
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Ahmed Hamed Attia Kotb Hussein Teaching Assistant CS Department
Network Fundamentals – Transport Layer