Context-Aware Middleware for Resource Management in the Wireless Internet US Lab 신현정

Abstract The provisioning of Web Services Over the Wireless Internet introduces novel challenging issues for service design and implementation In this scenario, there are Frequent provision time changes/ access terminal capabilities/ system management policies.

Development of context-dependent services - requires novel middle wares with full context visibility Propose a middle ware for context-aware resource management : CARMEN ① Automatic reconfiguration ② Determines the context on basis of metadata ③ Exploits the mobile agent technology to implement mobile middleware components ④ How metadata and mobile agents can favor component reusability/ automatic service reconfiguration

CONTENTS Context Aware Service Provisioning Resource Management For Mobility Metadata in CARMEN CARMEN Architecture CARMEN Shadow Proxies

Context Aware Service Provisioning Wireless Internet scenario has several specific characteristics The distinctive features of wireless Internet pose new challenges in retrieving and operating on distributed resources and undermine several assumptions of traditional service provisioning  The location and heterogeneity transparency

Service provisioning in the wireless Internet requires the visibility  Location information, system-level data (access device characteristics)  Information should be propagated up to the Service level  performing service configuration and delivery  Mobility determines changes in user location

Metadata Based Middleware Solutions for Context Management to support context-aware service provisioning. mobility and heterogeneity. Reconfiguration requirements should be expressed at a high level of abstraction by cleanly separating of concerns crucial to reduce complexity. Metadata can describe both the structure/meaning of the resources composing a system and the specification of management operations expressed at a high level of abstraction.

Metadata type I. Profile: characteristics, capabilities, requirements of users, devices and service components II. Policies: the choices ruling system behavior, separated from system implementation ① Access Control Policies ② Obligation Policies

The effectiveness of metadata adoption depends on the characteristics of the language used for metadata specification and of the runtime environment for the metadata support Metadata specification  should exploit declarative language  Simplify metadata reuse and modification  Facilitating the analysis of potential conflicts  Responsible for metadata distribution/deactivation/enforcement/ independently of service logic

Resource Management for Mobility Context changes force to consider the management issues of updating dynamically the binding of clients to resources

Resource movement strategy Copy movement strategy Remote reference strategy Rebinding strategy

There is a wide variety of basic and heterogeneous implementation mechanisms Adding mobility to proxies requires technologies to support Mobile Agents (MAs) implement technology of mobile proxies in the Wireless Internet

Mobile Agents for the Design of Mobile Proxies The properties of mobility, autonomy, asynchronous, and local resource exploitation typical of the MA programming paradigm are particularly suitable MAs can provide full decentralization of management control, definitely important to achieve scalability and to avoid management bottlenecks

Metadata in CARMEN CARMEN is a novel middleware for context-aware resource management Supports and facilitates the design, development, and deployment of context dependent services CARMEN allows service providers, system administrators, and final users to specify different kinds of metadata

CARMEN two types of metadata  Profiles : describe the characteristics of resource modeled in the system  Policies :manage migration, binding and access control Access control policies Mobility handling policies CARMEN adopts the Ponder language for policy specification.

CARMEN ARCHITECTURE

Metadata Manager  Supports the specification of the different kinds of CARMEN metadata Supporting the specification/update of profile information Dynamically installing/enforcing policies for access control and mobility handling

 MM is organized in three different logical modules Specification Module (SM) Obligation Coordinator (OC) Obligation Enforcer (OE)

Context Manager (CM)  CM is responsible for dynamically establishing the context of any CARMEN client, thus determining its resource visibility Event Manager (EM)  EM plays the crucial role of delivering the events relevant for triggering migration and binding policies

The CARMEN Shadow Proxies CARMEN middleware is centered on the distributed and dynamic deployment of context- aware mobile proxies CARMEN provides any user Shadow Proxies