Transcript Jini
A Study of Sun Microsystem’s Jini Architecture Casey Detorie CS522 11 December 2002 Purpose of Study • Develop solid understanding of Jini • Characterize the responsiveness of the Jini lookup service • Characterize the robustness of a simple Jini network What is Jini? • Sun’s Java-based network architecture • Implements Sun’s paradigm of “The Network is the Computer”: Work Req Result • Complements—not a substitute for--CORBA Jini Features • Extreme flexibility – Clients and services are decoupled – Jini lookup service • Robustness of network – Jini services are leased in lookup service • Ease of network growth – Discover and join protocols enable new services to join • Handles client-server synchronization issues – Clients register with lookup service for event notices Basic Jini Procedure Jini lookup service 2 1 3 Client 4 Service ‘A’ Key Roles of Lookup Service • • • • • • • Discovery for clients and services Provide lookup support for clients Return service proxy to client Event solicitations/notifications with clients Register/store service proxies Assign unique IDs to services Maintain leases for registrations and notifications Lookup Service Responsiveness • How responsive is the lookup service in terms of the time it takes to return a proxy to the client? – Ran two versions of client: • “Smart client”: Knew IP of service • “Dumb client”: Had to use lookup service – Compared times needed to complete server computation and get result back Lookup Service Responsiveness • Is response time affected by number of services registered in lookup service? – Repeated above experiment using 1, 2, and 3 services registered Jini Network Robustness • How quickly can a simple Jini network recover from a network outage while in mid-service to a client? – Set up two simple services and one client – Kill one server while it was servicing client – Determine time needed for backup service to recover Jini Conclusions • Intuitive solution to complex networking problems • Provides for adaptable, flexible, robust networks • Major limitation: requires use of Java JVM in most of network – What to do with mixed platform/OS/hardware networks? Results • Mixed and inconsistent – Heavily dependent on network traffic volume – Standard deviation seemed high – Further experimenting needed • Lookup Service Responsiveness – “Smart” vs. “Dumb” client: lookup service added ~3-8% additional time – Multiple services on lookup service: no significant penalty (simple array as registry data structure?) Results • Network Robustness – Recover relatively quick: ~250-500s – Possibly more complicated with more complex services Resources • Li, Sing. Professional Jini. Wrox Press Ltd. 2000. • www.jini.org • Sun Microsystems, Inc. The Jini Specification v1.2. • Edwards, Keith W. Core Jini. Pearson Education. 2000.