A Study of Sun Microsystem’s Jini Architecture Casey Detorie CS 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 Client 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: ~  s –Possibly more complicated with more complex services

Resources Li, Sing. Professional Jini. Wrox Press Ltd Sun Microsystems, Inc. The Jini Specification v1.2. Edwards, Keith W. Core Jini. Pearson Education