Modeling And Caching Strategy In Content Centric Networks For Marine Applications

With the rapid development of modern navigation industry,the requirements for the quality of maritime communication services are becoming higher and higher.Compared with traditional networks,the Content Centric Networks(CCN)is pro-posed to satisfy the future network needs.With faster data retrieval rate and higher communication security,CCN is a very effective content communication architecture.The CCN system is based on the concept of content naming data and provides securi-ty for the content itself,not the connection to the content,thus avoiding many host-related threats.The content replaces the traditional host address and becomes the core of the network.CCN decouples content from the host and supports data caching at the network layer,which helps to avoid duplicate delivery of the same content in the network and improve the transmission efficiency of data.In view of the develop-ment needs of marine information networks,this thesis focuses on the modeling and caching strategies of CCN.The specific research contents are as follows.Firstly,the development status and the challenges of the marine information network are presented,and the ship-based data transmission system in the Internet of Vessels is established as the experimental system model.Meanwhile,the network to-pology,request arrival distribution model and the distribution rules of the content popularity are discussed.Then,after briefly summarizing the cache research objects and strategies,the cache-hit ratio,the load of servers,the delay of a content request,the nodal flow and the number of route hops required to complete a data transmission are defined as the system evaluation indexes.After that,a comprehensive evaluation method based on entropy weight method is proposed to reduce the subjective impact and provide a rel-atively objective basis for the comprehensive evaluation of the multi-index system.In addition,an improved node cache capacity allocation strategy based on the node's service capability for the request is presented.The main idea of the strategy is to evaluate the ability of the node to satisfy the user data request by calculating the historical access data of the network through statistical analysis,and assign a suitable cache space to each node based on these evaluations.The experimental results show that the strategy can effectively improve the intra-network cache utilization of the system.At the same time,the strategy can also reduce the load pressure of the content source and the traffic load of the system,thereby reducing the operating pressure and the bandwidth requirements of the system.Besides,it can shorten the user request de-lay and improve the transmission efficiency of the system as well.Finally,the ability of the CCN to satisfy the user's service in the case of commu-nication link interruption is studied,which proves the high reliability of the CCN sys-tem.Moreover,a preliminary verification of the basic function implementation of the CCN system is completed.