Caching Mechanism in Publish/Subscribe Network

Content-based Publish/Subscribe network is a flexible communication model. It can support communication using the content of message instead of the network address, which will meet the need of data transmission in large scale. In traditional Publish/Subscribe network, messages are not stored in the network and subscribers can only receive the messages published while they are online. However, in some dynamic scenes where the users join and leave the system dynamically, a new user might be interested in the messages published in the past. This paper proposes a distributed caching algorithm to store messages and support subscribing to historical messages in Publish/Subscribe network, while maintaining the loosely coupled and asynchronous communication of the network. By comparing with the other two caching algorithms, the proposed caching algorithm outstands in persistence capacity, overhead of history retrieval, user response delay, and scalability.