socket programming project 2

8/2/2019 Socket Programming Project 2

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Socket Programming Project 2

Computer Networks


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Goal

Simulating a peer-to-peer file-sharing network

via ad-hoc connections using TCP and UDP

sockets.

10% of the final grade.

Individual Assignment

Cheating = F Grade Hardcode nunki.usc.edu NOT

68.181.201.3.


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Phases

The project has 3 major phases:

Registration of peers with the bootstrap server

Authentication of the content providers by the

bootstrap server

peer-to-peer content sharing.


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Sockets

Order of execution

bootstrap_server

peers (all 4 of them concurrently)

content_provider

Phases 1 and 2

all communications are through UDP sockets.

Phase 3

all the communications are over TCP sockets.


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Code Files

bootstrap_server

content_provider

You must create 2 concurrent content_providers

(by using fork() or a similar Unix system call).

peer

You must create 4 concurrent peers (by using

fork() or a similar Unix system call).


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Identifier String Message Payload

Any of the following strings:peer1, peer2, peer3, peer4provider1, provider2bootstrap

The actual content of themessage such as, names,port numbers or IP addresses

Identifier String Message Payload

Any of the following strings:peer1, peer2, peer3, peer4provider1, provider2bootstrap

The actual content of themessage such as, names,port numbers or IP addresses


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Bootstrap Server

UDP Port

Creates a text file directory.txt only ONCE.

Writes the information to it every time a newpeer registers itself with the bootstrap_server.

The bootstrap_server expects to hear

messages from all 4 peers before it receivesany messages from the content_providers.


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Bootstrap Server

Bootstrap Server must retrieve some

information from the message(s) and store

them on a single line (for each peer) separated

by one space in the file directory.txt:

senders name , e.g. peer1

its TCP port number, e.g. 3451

its IP address, e.g. 128.125.61.23

group number, e.g. group1


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Bootstrap Server

Authentication of the Content Provider

The bootstrap_server sends the filename

directory.txt as a message to that

content_provider.

Terminate bootstrap_server.


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Peer1

Peer3

Peer4

Peer2

BOOTSTRAP_SERVER

UDP

SOCKET

UDP

SOCKET

UDP

SOCKET

UDP

SOCKET


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Content Provider

Creates UDP socket and sends the username

and password to the bootstrap_server.

Receives filename.

Read the files in turn and find the peers that

subscribed to them.

Group# defines which peer subscribed to the

content_provider.


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UDP

SOCKET

Content_Provider2

Peer1

Peer3

Peer4Peer2

BOOTSTRAP_SERVER

UDP

SOCKET

Content_Provider1


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Content Provider

Identifies the peers.

Opens up a TCP connection

Sends the count of the number of peers andwelcome message to the peer.

Receives an ACK from the peer for every

message.


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Content Provider

The content provider then sends the names

and TCP port numbers of the rest of its peer

subscribers to this peer subscriber in one long

message or several short messages.

Tears down the TCP connection


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Peers

TCP/ UDP sockets

It then sends a message through the UDP

socket to the bootstrap_server. This message

contains its TCP port number, its IP address

and a randomly chosen group number (either

group1 or group2).

Checks whether the message is from the

Content Provider or a Peer.


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Peer1

Peer3

Peer4

Peer2

BOOTSTRAP_SERVER

UDP

SOCKET

UDP

SOCKET

UDP

SOCKET

UDP

SOCKET


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Peers

First peer has a number and a list of the

names and the TCP ports of the other peer

subscribers .

It first checks the number. If the number is

greater than 1, it decrements it by 1 and

establishes a new TCP connection through its

TCP socket to contact the first peer subscriberin this list.


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Peers

Once the connection is accepted, it sends this

new number, the sentence welcome to group

# and the names and the TCP port numbers

of the rest of the subscribers in one longmessage or several short ones.

This goes on iteratively till the last peer is

reached.


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TCPSOCKET

Content_Provider2

Peer1

Peer3

Peer4

Peer2

TCPSOCKET

Content_Provider1

Group1

Group2

TCPSOCKET

TCPSOCKET

STEP 1

STEP 2

STEP 3


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Other Instructions

Assumptions

Requirements

Grading Criteria Cautionary Words

Etc

socket programming project 2

Documents