Proxy-based hybrid cache management in Mobile IP systems

In this paper, we propose and analyze a proxy-based hybrid cache management scheme for client–server applications in Mobile IP (MIP) networks. We leverage a per-user proxy as a gateway between the server and the mobile host (MH) such that any communication between the MH and server must pass through the proxy. The proxy has dual responsibilities in our design. It keeps track of the current location of the MH by acting as a regional Gateway Foreign Agent (GFA) as in the MIP Regional Registration protocol for mobility management. The proxy is also responsible for cache consistency management and query processing on behalf of the MH. To reduce the network traffic, a threshold-based hybrid cache consistency management policy is applied. That is, when a data object is updated at the server, the server sends an invalidation report to the MH through the proxy to invalidate the cached data object, provided that the size of the data object exceeds the given threshold. Otherwise, the server sends a fresh copy of the data object through the proxy to the MH. We identify the best “threshold” value that would minimize the overall network traffic incurred due to mobility management, cache consistency management, and query processing, when given a set of parameter values characterizing the operational and workload conditions of the MIP network. © 2007 Elsevier B.V. All rights reserved.