Peer to Peer Network Anas Hardan

What is a Network? What is a Network? A network is a group of computers and other devices (such as printers) that are connected by some type of transmission media. A network is a group of computers and other devices (such as printers) that are connected by some type of transmission media. Networks may be as small as two computers connected by a cable in a home office or as large as several thousand computers connected across the world via a combination of cable, phone lines, and satellite links. Networks may be as small as two computers connected by a cable in a home office or as large as several thousand computers connected across the world via a combination of cable, phone lines, and satellite links.

Why Use Networks? Why Use Networks? Networks enable multiple users to: Networks enable multiple users to: Share devices like printers. Share devices like printers. Data like spreadsheet files. Data like spreadsheet files. Sharing devices saves money. Sharing devices saves money. Sharing devices also saves time. Sharing devices also saves time. Another advantage to networks is that they allow you to manage, or administer, resources on multiple Another advantage to networks is that they allow you to manage, or administer, resources on multiple computers from a central location. computers from a central location.

network models: network models: Peer-to-Peer Peer-to-Peer Client/Server Client/Server

Peer-to-Peer Networks Peer-to-Peer Networks The simplest form of a network is a peer-to-peer The simplest form of a network is a peer-to-peer network. network. In a peer-to-peer network, every computer can In a peer-to-peer network, every computer can communicate directly with every other computer. communicate directly with every other computer. Each computer can be configured to share only Each computer can be configured to share only some of its resources and keep other resources some of its resources and keep other resources inaccessible to the network. inaccessible to the network. Every computer has the ability to send and receive Every computer has the ability to send and receive information from every other computer. information from every other computer.

Peer-to-Peer Networks

P2P File Sharing Networks P2P file sharing systems have become the single most popular class of Internet applications in this decade. P2P file sharing systems have become the single most popular class of Internet applications in this decade. A P2P network implements search and data transfer protocols above the Internet Protocol (IP). To access a P2P network, users simply download and install a suitable P2P client application. A P2P network implements search and data transfer protocols above the Internet Protocol (IP). To access a P2P network, users simply download and install a suitable P2P client application.

How second generation P2P services worked Gnutella2: Hubs are used to quickly search for files, eliminating the original "find peer and search" method. Instead, they store a list of files on all the "Leaves" (A peer) that are connected to it, thus dramatically reducing search time. Advantages: if a hub crashes, it's network stays alive. Disadvantages: Doesn't make network any more durable than the first generation of P2P. Gnutella2: Gnutella2: Hubs are used to quickly search for files, eliminating the original "find peer and search" method. Instead, they store a list of files on all the "Leaves" (A peer) that are connected to it, thus dramatically reducing search time. Advantages: if a hub crashes, it's network stays alive. Disadvantages: Doesn't make network any more durable than the first generation of P2P. Gnutella2:

FastTrack: Programs such as Kazaa and iMesh use the FastTrack protocol. Normal peers connect to a super node which acts just like a hub. Super nodes also connect to other super nodes, allowing search requests to move through the network very quickly. Peers then establish a direct connection to a client after a file has been found. Advantages: Any client can become a super node. Disadvantages: Corruption of files occur. Clients include: Kazaa ( iMesh ( FastTrack: Programs such as Kazaa and iMesh use the FastTrack protocol. Normal peers connect to a super node which acts just like a hub. Super nodes also connect to other super nodes, allowing search requests to move through the network very quickly. Peers then establish a direct connection to a client after a file has been found. Advantages: Any client can become a super node. Disadvantages: Corruption of files occur. Clients include: Kazaa ( iMesh (

BitTorrent:.torrent files are used to store information about the file being shared. Once a torrent file is opened, the client connects to the tracker which tells the client where the file is located and what other peers/seeders there are. BitTorrent works by chunks of small files being transferred (even through multiple connections), while you are downloading. The files are checked for corruption as the download continues. Leeches are people who download and don't upload, and are highly frowned upon on some sites, disallowing them from downloading any further. Advantages: Very fast. Disadvantages: Trackers are unreliable and if it goes down, the file is lost. BitTorrent:.torrent files are used to store information about the file being shared. Once a torrent file is opened, the client connects to the tracker which tells the client where the file is located and what other peers/seeders there are. BitTorrent works by chunks of small files being transferred (even through multiple connections), while you are downloading. The files are checked for corruption as the download continues. Leeches are people who download and don't upload, and are highly frowned upon on some sites, disallowing them from downloading any further. Advantages: Very fast. Disadvantages: Trackers are unreliable and if it goes down, the file is lost.

EDonkey Network: Edonkey runs on the same principle as first generation P2P, only anybody can become a server. Clients communicate with the server to download files, and random chunks can be downloaded in any order then put together in the end. Advantages: No file corruption, leech penalization. Disadvantages: It can penalize users unfairly. EDonkey: EDonkey Network: Edonkey runs on the same principle as first generation P2P, only anybody can become a server. Clients communicate with the server to download files, and random chunks can be downloaded in any order then put together in the end. Advantages: No file corruption, leech penalization. Disadvantages: It can penalize users unfairly. EDonkey:

The advantages They are simple to configure. They are simple to configure. They are typically less expensive to set up and maintain than other They are typically less expensive to set up and maintain than other types of networks. types of networks. Users control individual shared resources. Users control individual shared resources. No need of a network administrator. No need of a network administrator.

disadvantages They are not very flexible - As a peer-to- peer network grows larger, adding or changing significant elements of the network may be difficult. They are not very flexible - As a peer-to- peer network grows larger, adding or changing significant elements of the network may be difficult. They are also not necessarily secure - meaning that in simple installations, data and other resources shared by network users can be easily discovered and used by unauthorized people They are also not necessarily secure - meaning that in simple installations, data and other resources shared by network users can be easily discovered and used by unauthorized people They are not practical for connecting more than a handful of computers, because they do not always centralize resources. They are not practical for connecting more than a handful of computers, because they do not always centralize resources.