Data caching is a technique that can be used by web servers to speed up the response time of client requests. Dynamic websites are becoming more popular, but they pose a problem –- it is difficult to cache dynamic content, as each user may receive a different version of a webpage. Caching fragments of content in a distributed way solves this problem, but poses a maintainability challenge: cached fragments may depend on other cached fragments, or on underlying information in a database. When the underlying information is updated, care must be taken to ensure cached information is also invalidated. If new code is added that updates the database, the cache can very easily become inconsistent with the underlying data. The deploy-time dependency analysis method solves this maintainability problem by analyzing web application source code at deploy-time, and statically writing cache dependency information into the deployed application. This allows for the significant performance gains distributed object caching can allow, without any of the maintainability problems that such caching creates.

Data caching is a technique that can be used by web servers to speed up the response time of client requests. Dynamic websites are becoming more popular, but they pose a problem –- it is difficult to cache dynamic content, as each user may receive a different version of a webpage. Caching fragments of content in a distributed way solves this problem, but poses a maintainability challenge: cached fragments may depend on other cached fragments, or on underlying information in a database. When the underlying information is updated, care must be taken to ensure cached information is also invalidated. If new code is added that updates the database, the cache can very easily become inconsistent with the underlying data. The deploy-time dependency analysis method solves this maintainability problem by analyzing web application source code at deploy-time, and statically writing cache dependency information into the deployed application. This allows for the significant performance gains distributed object caching can allow, without any of the maintainability problems that such caching creates.

In this dissertation research, we design and analyze integrated mobility and service management for network cost minimization in Wireless Mesh Networks (WMNs). We first investigate the problem of mobility management in WMNs for which we propose two efficient per-user mobility management schemes based on pointer forwarding, and then a third one that integrates routing-based location update and pointer forwarding for further performance improvement. We further study integrated mobility and service management for which we propose protocols that support efficient mobile data access services with cache consistency management, and mobile multicast services. We also investigate reliable and secure integrated mobility and service man agement in WMNs, and apply the idea to the design of a protocol for secure and reliable mobile multicast. The most salient feature of our protocols is that they are optimal on a per-user basis (or on a per-group basis for mobile multicast), that is, the overall network communication cost incurred is minimized for each individual user (or group). Per-user based optimization is critical because mobile users normally have vastly different mobility and service characteristics. Thus, the overall cost saving due to per-user based optimization is cumulatively significant with an increasing mobile user population. To evaluate the performance of our proposed protocols, we develop mathematical models and computational procedures used to compute the network communication cost incurred and build simulation systems for validating the results obtained from analytical modeling. We identify optimal design settings under which the network cost is minimized for our mobility and service management protocols in WMNs. Intensive comparative performance studies are carried out to compare our protocols with existing work in the literature. The results show that our protocols significantly outperform existing protocols under identical environmental and operational settings. We extend the design notion of integrated mobility and service management for cost minimization to MANETs and propose a scalable dual-region mobility management scheme for location-based routing. The basic design concept is to use local regions to complement home regions and have mobile nodes in the home region of a mobile node serve as location servers for that node. We develop a mathematical model to derive the optimal home region size and local region size under which overall network cost incurred is minimized. Through a comparative performance study, we show that dual-region mobility management outperforms existing mobility management schemes based on static home regions. / Ph. D.

Caching is a widely used technique to improve the scalability of distributed systems. A central issue with caching is maintaining object replicas consistent with their master copies. Large distributed systems, such as the Web, typically deploy heuristic-based consistency mechanisms, which increase delay and place extra load on the servers, while not providing guarantees that cached copies served to clients are up-to-date. Server-driven invalidation has been proposed as an approach to strong cache consistency, but it requires servers to keep track of which objects are cached by which clients. We propose an alternative approach to strong cache consistency, called MONARCH, which does not require servers to maintain per-client state. Our approach builds on a few key observations. Large and popular sites, which attract the majority of the traffic, construct their pages from distinct components with various characteristics. Components may have different content types, change characteristics, and semantics. These components are merged together to produce a monolithic page, and the information about their uniqueness is lost. In our view, pages should serve as containers holding distinct objects with heterogeneous type and change characteristics while preserving the boundaries between these objects. Servers compile object characteristics and information about relationships between containers and embedded objects into explicit object management commands. Servers piggyback these commands onto existing request/response traffic so that client caches can use these commands to make object management decisions. The use of explicit content control commands is a deterministic, rather than heuristic, object management mechanism that gives content providers more control over their content. The deterministic object management with strong cache consistency offered by MONARCH allows content providers to make more of their content cacheable. Furthermore, MONARCH enables content providers to expose internal structure of their pages to clients. We evaluated MONARCH using simulations with content collected from real Web sites. The results show that MONARCH provides strong cache consistency for all objects, even for unpredictably changing ones, and incurs smaller byte and message overhead than heuristic policies. The results also show that as the request arrival rate or the number of clients increases, the amount of server state maintained by MONARCH remains the same while the amount of server state incurred by server invalidation mechanisms grows.