An Efficient Caching Scheme and Consistency Maintenance in Hybrid P2P System

Peer-to-peer overlay networks are widely used in distributed systems. P2P networks can be divided into two categories: structured peer-to-peer networks in which peers are connected by a regular topology, and unstructured peer-to-peer networks in which the topology is arbitrary. The objective of this work is to design a hybrid peer-to-peer system for distributed data sharing which combines the advantages of both types of Peer-to-peer networks and minimizes their disadvantages. Consistency maintenance is propagating the updates from a primary file to its replica.

Adaptive consistency maintenance algorithm (ACMA) maintains that periodically polls the file owner to update the file due to minimum number of replicas consistency overhead is very low. Top Caching (TC) algorithm helps to boost the system performance and to build a fully distributed cache for most popular information. Our caching scheme can deliver lower query delay, better load balance and higher cache hit ratios. It effectively relieves the over-caching problems for the most popular objects.

Existing System:

In the past decade a number of prototype peer-to-peer information retrieval systems have been developed. Unfortunately, none of these has seen widespread real-world adoption and thus, in contrast with file sharing, information retrieval is still dominated by centralized solutions. In this article we provide an overview of the key challenges for peer-to-peer information retrieval and the work done so far. We want to stimulate and inspire further research to overcome these challenges. This will open the door to the development and large-scale deployment of real-world peer-to peer information retrieval systems that rival existing centralized client-server solutions in terms of scalability, performance, user satisfaction, and freedom.

Proposed System:

We propose a hybrid peer-to-peer system for distributed data sharing which combines the structured and unstructured peer-to-peer networks. In the proposed hybrid system, a structured ring-based core network forms the backbone of the system and multiple unstructured peer to peer networks are attached to the backbone and communicate with each other through the backbone. The core-structured network provides an accurate way to narrow down the queried data within a certain unstructured network, while the unstructured networks provide a low cost mechanism for peers to join or leave the system freely.

The core network which forms the backbone of the hybrid system; the second part is made of multiple unstructured peer-to-peer networks each of which is attached to a node in the core network. The core structured network can narrow down the data lookup within a certain unstructured network accurately, while the unstructured networks provide a low-cost mechanism for peers to join or leave the system freely.


  • Core Transit Network
  • Stub Network
  • Idea of Hybrid Peer
  • Consistency Algorithm

Tools Used:

Front End : JAVA