This PPT is about TCP Listen and accept function and it is explaining three way handshaking also

1. What is a socket ?
It is an interface between
application layer and transport
layer within a host.
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2. Application Layer
Transport Layer
Socket
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3. Why socket ?
Kannadasan Yamuna
For Identification
?
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4. Why socket ?
Hostel Name + Room No
IP address + Port number
Socket
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5. listen() accept()
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6. listen()
 Called only by TCP server
 Performs two actions
 Convert the socket in to passive socket
 Specify the maximum number of connections the kernel
should queue
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7.  For a listening socket the kernel maintains two queues
 An incomplete connection queue
 Waiting for 3-way handshake
 A complete connection queue
 Completed 3-way handshake
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8. 3-way handshaking
client server
Connect called Create entry on
incomplete queue
Connect returns
Entry moved from
incomplete queue to
complete queue
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9. int listen(int sockfd, int backlog)
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10. Questions ?
 What is the default size of backlog ?
 Which queue is longest one (complete/incomplete) ?
 What will happen when queue is full ?
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11. accept()
Completed
connection queue
Incomplete
connection queue
Arriving
SYN
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12. accept()
int accept(int sockfd, socket addr, socket addrlen)
 If success return a brand new descriptor
 ie descriptor of connected socket.
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13. References
 Unix Network Programming
 W.Richard Stevens
 Computer Networking a top down approach
 James F Kurose
 Wikipedia
 pubs.opengroup.org
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14. Questions
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