The Assignment-2 Specification and Marking Criteria
Peer-to-Peer (P2P) is a type of distributed systems, in which every
peer is both a client to request services from other peers and a server
to provide services to other peers. Chapter 10 of the textbook focuses
on P2P systems and there are a lot of published academic articles about
P2P systems such as:
Rodrigues, R., Druschel, P., 2010. Peer-to-Peer Systems,
Communications of the ACM. 53(10), 72-82. (available at
http://zoo.cs.yale.edu/classes/cs426/2012/bib/rodrigues10peer-topeer.pdf
on 8th May 2017).
You may need to access the above resources for conceptual
understanding of P2P. However, the knowledge and programming skills that
you need for this assignment are the TCP streaming and UDP datagram
communication between client/server. The unit lab has practised a number
of projects for TCP and UDP for client/server communication; in this
assignment you will need integrate both the client and the server
components into a peer. To complete this assignment, you need to
complete the following 2 parts.
Part 1: Peer Programming
Among many P2P applications, file sharing is a typical application
to share available files across all peers of an overlay. In this part,
you are to develop a simplified P2P file sharing system. The assumptions
on the system are specified as follows.
1. Peers form a networking overlay by IP multicast (reference to
Chapter 4.4 of the textbook, Week 5 lecture slides, Week 6 lab projects,
and search for other academic articles about IP multicast if
necessary).
2. Each peer has a unique ID.
3. Each peer possesses a number of files that can be shared by other peers.
4. Each peer multicasts a file sharing request to all other peers in
the overlay. The requested file can always be found but can be found
from a single peer only.
5. Once the file is found, the peer, which requests the file, will download the file from the peer, which possesses the file.
6. The shared files are just in plain text format only.
The following screenshots show an implementation of the above file sharing system.
1. 3 peers (with ID of PPP1, PPP2 and PPP3) joined the same IP
multicast group. Note: 228.5.6.7 and 8888 are the IP multicast address
and port number that were used in this example.
2. At the beginning, PPP1 possessed file1, PPP2 possessed file2 and PPP3 possessed file3.
3. PPP1 requests file2, which was found in PPP2 and then downloaded from PPP2 into PPP1.
4. PPP2 requests file3, which was found in PPP3 and then downloaded from PPP3 into PPP2.
5. PPP3 requests file1, which was found in PPP1 and then downloaded from PPP1 into PPP3.
The above example shows the equity between peers, that is, every peer is both a client and a server to share files.
To implement the framework, you need to implement. The peer’s main
thread for starting the application. The main thread will create at
least two independent threads, of which one is responsible for sending a
request to all other peers by IP multicast and downloading the found
file from a peer, and the other thread is responsible for sending a file
once it is requested by other peers. In addition, it is required to use
UDP protocol for IP multicast of requests and to use TCP protocol for
file sending/downloading. Note: a good practice is to implement the 3
threads by 3 Java classes like Peer.class, PeerService1.class and
PeerService2.class in the above screenshots.
Part 2: Documentation
After the implementation of the framework, prepare a document to include:
1. An end user’ instruction about how to use your system.
2. Any suggestions about possible improvement of the proposed system. Submission
You need to provide the following files in your submission.
1. Files of Java source code of the implementation. The in-line
comments on the data structure and program structure in the programs are
required. These source code files must be able to be compiled by the
standard JDK (Java Development Kit) or NetBeans from Oracle
(http://www.oracle.com/technetwork/java/index.html).
2. The compiled Java class files of the source code. These Java
classes must be runnable on the standard Java Runtime Environment (JRE)
or NetBeans from Oracle
(http://www.oracle.com/technetwork/java/index.html).
3. A Microsoft Word document to address the issues as specified in Part 2 above.
All the required files must be compressed into a zip file for
submission. You must submit your assignment via the online submission
system from the unit web site. Any hardcopy or email submission will not
be accepted. After the marked assignments are returned, any late
submissions will not be accepted.
The Marking Criteria
Marking Criteria Available Marks
Part 1: Peer Programming (compilable Java source code file with necessary in-line comments, runnable Java class files) 27.0
1. The peer’s main application 4.0
• Create and join the multicast group 2.0
• Create service threads 2.0
2. Requests multicasting (UDP protocol) 7.0
• Continuously accept a user’s input file name 2.0
• Construct a request to include enough information for file sharing 3.0
• Use UDP to multicast the request 2.0
3. Request process 7.0
• Only process the multicast requests from other peers 2.0
• Check whether the peer has the requested file 3.0
• Send the requested file (if applicable) 2.0
4. File download (TCP Protocol) 9.0
• Use TCP to create a data stream 4.0
• Receive the file from the date stream 3.0
• Save the file into the permanent storage 2.0
Part 2: Documentation 8.0
1. Program use and test instruction 6.0
• Compiling and installation instruction are clear 2.0
• Test instruction covers the application scenario 2.0
• Necessary screenshots are provided 2.0
2. Suggestions for improvement 2.0
Sub Total for Assignment-2 35.0
Late Penalty -1.75 (5% each calendar day)
Plagiarism Penalty
Total for Assignment-2
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