Distributed Systems: Principles and Development

Peer-to-Peer Overlay and File Sharing

In distributed computing, a peer is both a client and a server at the same time, being able to request services from other peers or providing services to other peers. For the general knowledge about peer, you can read the following academic article.

Rodrigues, R., Druschel, P., 2010. Peer-to-Peer Systems, Communications of the ACM. 53(10), 72-82.

In this assignment, you are to develop programming skills of peer via a particular application - Peer- to-Peer Overlay and File Sharing. Among many Peer-to-Peer (P2P) applications, file sharing is a typical application to share available files across all peers of an overlay. In this assignment, you will need to upgrade a client and a server into a peer. The peers are to form an overlay by IP multicast and the files of a peer can be shared by any other peers. When a peer needs a file, it will multicast the file name to the peer overlay and the peer that has the file will upload the file to the requester peer. To search for a file, a UDP datagram via IP multicast is used. Once the file is found, upload/download of the file is to use TCP streaming to fit for any possible type and length of the file. To complete this assignment, you need to complete the following 2 parts.

Part 1: Peer overlay design and implementation

In this part, you are to develop the 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 has a number of files that can be shared by other peers.

4. Each peer can multicast a file sharing request to all other peers in the overlay. To simplify the problem, we assume that the request file can always be found and can only be found from a single peer.

5. Once the file is found, the requester peer (the one who requests the file) will download the file from the supplier peer (the one who possesses the file).

6. The shared files can be in any type and any length.

7. A peer needs to ignore the requests from itself because by default IP multicast sends a message to every peer on the overlay.

The following screenshots show an implementation of the above file sharing system.

1. The 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 has the file IPDPS2017.pdf, PPP2 has the file CloudComputing.jpg and PPP3 has the file OneMoreNight.mp3.

3. PPP1 requests CloudComputing.jpg, which is found in PPP2 and then downloaded from PPP2 into PPP1.

4. PPP2 requests OneMoreNight.mp3, which is found in PPP3 and then downloaded from PPP3 into PPP2.

5. PPP3 requests IPDPS2017.pdf, which is found in PPP1 and then downloaded from PPP1 into PPP3.

Note: you will need to check that the original file and the downloaded file are exactly the same. For example to open IPDPS2017.pdf of PPP1 and Download-IPDPS2017.pdf of PPP3, you will ensure the 2 files are the same without any corruption.

The attached example shows the equity between peers, that is, every peer is both a client and a server to share files. Your implementation must satisfy all the above requirements in order to get full marks.

Part 2: Documentation

After the implementation of the framework, prepare a document to include:

1. An end user' instruction about how to compile, run and test your system.

2. The key issues about upgrading a client and a server to a peer and overlay forming.

Submission

You need to provide the following files in your submission.

1. At least 3 peers in 3 individual folders, of which each folder contains:

• 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.
• The compiled Java class files of the source code. These Java classes must be runnable on the standard JRE (Java Runtime Environment) or NetBeans from Oracle.

• At least 1 file for file sharing test

2. 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.

Attachment:- assignment.rar