| Server load is an important indicator of Internet application availability,and it’s an attractive field to alleviate it in face of mass requests.Traditionally,CDN,short for Content Delivery Network,is employed to reduce server load.However,traditional CDN has flaws in its high cost and complexity of management.This paper firstly proposes the Decentralized Content Delivery Network,with which web browsers are assembled into a loosely-connected decentralized network by using WebRTC.This decentralized network is able to share the content serving requests,so that central resource servers do not have to suffer high load.Thus we design and implement the WebRTC based Decentralized Content Delivery Network,named NodeCDN,which consists of two subsystems,in particular,the Resource Exchange Subsystem,for the purpose of enabling node to fetch required resources and also act as a distributor,while the Signalling Service Subsystem,to establish the WebRTC channels among nodes to communicate with each other directly.Furthermore,we prove the convergence of resource search process mathematically,followed by the experiment and evaluation on the effect on server load,bandwidth consuming and resource fetch latency after applying NodeCDN.In addition,the performance and scalability of Signalling Service Subsystem is evaluated independently.As a result,NodeCDN shows its usefulness and effectiveness by reducing server load significantly,improving the usability of Internet application without adding cost of management. |
