114101403 network programming week one orientation

7/30/2019 114101403 Network Programming Week One Orientation

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Network programming

Manjunath.


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Administrative issues (1)

Instructors: Manjunath Mattam

Moodle and Mediawiki support: Mohana Krishna

Group mailing list: [email protected]

Courses slides, tasks, readings, in local mediawiki.

Submissions in moodle only. Text book:UNIX Network Programming Volume 1,

Third Edition: The Sockets Networking API Other text books available in references section.
mailto:[email protected]:[email protected]


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Administrative issues (2)

Grading: is done based on tasks, vivas, demos, presentations, homeworks, reading assignments.

Exam/ concept test conducted, scores are reflected in final grade.

The deadline for any assignment can be extended with a 10%penalty per day.

Deliverables are not accepted if the scheduled week is over.

Collaboration and plagiarism

Students are encouraged to talk to each other, to the TA, to thementor or to any one else about assignment. Any assistancethough must be limited to discussions. Student must write/code

his/her own work. Detailed plagiarism policy is available in Logistics page.


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Why network programming?

Discipline of designing and implementing

network programs.

Single program can communicate with

other computers on network.

Add power to simple programs.

How to program in network?


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What is a socket?

End point, of a bidirectional inter processcommunication flow across internet protocolbased computer network.

Interface between an application and transportlayer.

Socket address is a combination: IP address

Port Protocol (?)

Stream sockets & Datagram sockets

SOCK_STREAM , SOCK_DGRAM.


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How to create a socket?

Using socket function:

int socket(int domain, int type, int protocol);

Example: int sockfd;

Sockfd = socket(AF_INET, SOCK_STREAM,0);

If protocol is set to 0, then we let socket decide what protocol to usedepending on type.

Socket function returns socket descriptor, if an error then returns -1.


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Socket Structures

What is the size of IPv4 network address?

32 bit


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Byte Order

Functions to convert from host to network byte order and vice versa.

htonl, htons, ntohl, ntohs

Humans vs. sockets? Convert internet address to socketaddress or ascii. inet_aton or inet_ntoa


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TCP Socket

Assign local

port address

to socket.

Used by client to

connect withserver.

int listen(sockfd,

int backlog);

Maximum no of

connections to

queue for socket.

Listens or waits for

connect requests. Accept

incoming requests

directed to this socket.


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SocketAPI


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Socket Programming

1. socket2. bind

3. connect

4. listen

5. accept

6. send,recv7. sendto, recvfrom

8. close, shutdown

9. getpeername

10. gethostname


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UDP Socket


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Concurrency

Ability to handle more than one client at a time.

Use inherent operating system multi tasking capabilities.


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fork


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What is port?

What is socket?


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Thank you

114101403 network programming week one orientation

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