This introductory course on peer-to-peer networks explains how a P2P protocol delivers reliable data transfer services across unreliable transmission lines or networks. Unlike in a server client configuration, a peer-to-peer network allows network nodes to receive and also to share services and resources from other nodes in the network. This includes meticulous verification and authenticity of the origin of data using certified private and public keys. You will discover how these keys ensure the network element’s authenticity and safeguards it from malicious hackers. The course then shows how a voice channel is set up using session initiation protocol (SIP) based on a client’s IP (Internet protocol) address and port number. The differences between a leaf node, root node and a bootstrap and their functions are explained. The functions of the finger table and distributed hash table (DHT) are illustrated using appropriate diagrams.

The next module describes the logarithmic partitioning process as a means to quicken the process of the discovery and insertion of a new network node. You will explore how the node identifies other network elements by regularly updating its registry or address book. Use of the certificate verification process, one-time-pins (OTP) and location related IP addressing to increase security and authenticity of data are highlighted. Query and publish messages are used to explain the process of handshaking and redistribution of information in the DHT configuration. A publish message comes about when a node wishes to enter a network and wants to alert other nodes of its existence. A query message comes in when the network node has been requested to provide information about its name and the location by another node ie root node. Static and dynamic partitioning of node IDs in the node ID space is discussed by showing the advantages and disadvantages of each type in the performance of network processes.

While P2P systems have been used in many application domains, the concept was popularized by file-sharing systems such as music-sharing applications like Napster. The peer-to-peer crusade allowed millions of Internet users to join directly, form groups, and collaborate to form user-created search engines, file systems, and virtual supercomputers. The early Internet was more open than the present day, where two computers could have connected to the Web by sending packets to each other without firewalls and other security restrictions. This is different from the Web's broadcasting-like structure as it has developed since. Structures like Usenet, a distributed messaging scheme that was often described as an early peer-to-peer design, were established. It was a system that enforces a decentralized model of control. On the other hand, news servers would communicate with one another as peers to propagate news articles over the whole group of network servers. The same idea applies to SMTP email in the sense that the main email-relaying network of mail transfer agents has a P2P character, only the endpoint connected to the client has a client-server relationship. Peer-to-peer technology is quickly taking centre stage. Don’t be left behind, start upgrading yourself with this course today!