2JiniTM
Network Technology
©2001KwangShinOH
Http://raytrust.pe.kr
Agenda
 Why JiniTM
?
 What is JiniTM
?
 JiniTM
Architecture Overview
 The Details
 Example Service Model
 JiniTM
Roadmap
 Reference

3JiniTM
Network Technology
©2001KwangShinOH
Why JiniTM
?
 Distributed computing is more
difficult than local computing
because of :
 Network latency
 Concurrency issues
 Memory management
 Inevitable partial failure

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Network Technology
©2001KwangShinOH
Evolution of distributed
computing
Key insight : Remote increasingly looks
local

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Network Technology
©2001KwangShinOH
What is JiniTM
?
 Jini addresses the problems of
distributed computing using a set
of simple interfaces and protocols
 Jini enables spontaneous network
of software services(and devices)
to assemble into working groups of
objects, or Federations
 Jini builds on the JavaTM
2 Platform

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Network Technology
©2001KwangShinOH
What is JiniTM
?
 Jini enables self-healing when one
or more devices are removed from
the Federation
 Jini is usable for hardware as well
as software services
 Everything is represented by Java
Objects
 Everything is located and accessed
through Java Interfaces

7JiniTM
Network Technology
©2001KwangShinOH
JiniTM
Architecture
Overview

8JiniTM
Network Technology
©2001KwangShinOH
Http://raytrust.pe.krJava Technology
Features that Benefit
JiniTM
Feature Benefit
Java Virtual Machine  Homogeneous network
Portable object code  Architecture
independence
Downloadable code  Dynamic environment
Unified type system  No impedance mismatch

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Network Technology
©2001KwangShinOH
JiniTM
Extends the Java
Platform

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Network Technology
©2001KwangShinOH
The Details :
Jini Infrastructure

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Network Technology
©2001KwangShinOH
JiniTM
Lookup
Service
 Repository of available services
 Stores each service as Java objects
 Clients download services on
demand

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Network Technology
©2001KwangShinOH
Lookup service
 May be federated with other
lookup services
 Lookup service interface
provides:
 Registration
 Access
 Search
 Removal

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Network Technology
©2001KwangShinOH
Discovery and Join
Protocols
 Used to find and join a group of
services
 Based on UDP multicast
 Services advertise capabilities
 Provide required software
drivers
 Establish reference with lookup
service
 Unicast discovery also

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Network Technology
©2001KwangShinOH
Discovery Protocol

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Network Technology
©2001KwangShinOH
Discovery Protocol –
1
 The Multicast Request Protocol
 allows an entity that has just been
started to actively discover nearby
lookup servicesDiscovering Entity Lookup Service
multicast request
multicast response
unicast request
unicast response
Join Protocol

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Network Technology
©2001KwangShinOH
2
 The Multicast Announcement
Protocol
 allows lookup services to announce their
availability within multicast radiusDiscovering Entity Lookup Service
multicast announce
unicast request
unicast response
Join Protocol

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Network Technology
©2001KwangShinOH
3
 The Unicast Discovery Protocol
 allows an entity that has just been
started to directly discover known lookup
serviceDiscovering Entity Lookup Service
unicast request
unicast response
Join Protocol

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Network Technology
©2001KwangShinOH
Join Protocol

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Network Technology
©2001KwangShinOH
Join Protocol
 The Join Protocol
Joining Entity Lookup Service
service registration
new lease
Discovery Protocol
lease renew
lease renewal
lease expire

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Network Technology
©2001KwangShinOH
Steps in Discovery and
Join
 JiniTM
enabled Object(representing a
hardware and/or software service)
multicasts a packet with a reference
to itself
 The service receives RMI reference
to Lookup service(one or more)
 The Service joins a Federation by
placing an object representing its
capabilities into the Lookup service
for other clients and services to use

21JiniTM
Network Technology
©2001KwangShinOH
Traditional Technology
1. Device is added to computer
2. Device definition is edited in
node configuration table
3. Computer is restarted
4. Updated configuration table is
pushed to network device map

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Network Technology
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Jini Technology
1. Device is plugged in and
powered up
1. Lookup service receives multicast
2. Lookup service authenticates source
3. Lookup service sends advertisement
4. Device joins Lookup service

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Network Technology
©2001KwangShinOH
Finding a Service
 To find a service, a Jini client
locates service by querying a
Lookup Service by type(Java
Interface)
 Code moves from service to client
via Lookup Service
 Code needed to use service is
dynamically loaded on demand

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Network Technology
©2001KwangShinOH
Finding a Service

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Network Technology
©2001KwangShinOH
Using a Service
 Communication is between
service and its proxy
 Independent of wire protocol
 Protocol can change without
affecting client
 RMI semantics core to
functionality

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Network Technology
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Using a Service

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Network Technology
©2001KwangShinOH
Why JiniTM
uses RMI
 RMI can pass entire Java objects
and their code
 Works in any compliant JVM
 Provides automatic serialization,
transport, and de-serialization of
objects
 Robust and configurable security
options(RMI over SSL,
Authenticated Principal, etc.)

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Network Technology
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The Details :
Jini Services

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Network Technology
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Services
 Represented by Java Interfaces
 Separation of “how” from “what”
 Implement in hardware or software
 Implementations can change over
time
 Multiple implementations

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Network Technology
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Services Enable
Evolution
 Base interfaces can be extended to :
 Add new functionality
 Combine functionality
 Old clients can use base interface
 New clients can use extended
interface
 Allows evolution of implementation
without changing clients or
infrastructure

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Network Technology
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Services Are Defined
by Java Interfaces

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Network Technology
©2001KwangShinOH
Services Are Defined
by Java Interfaces

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Network Technology
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Client Finds Service
by Interface

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Network Technology
©2001KwangShinOH
by Interface

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Network Technology
©2001KwangShinOH
by Interface

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Network Technology
©2001KwangShinOH
Service Interfaces
 Community driven
 Printing
 Service UI
 Don’t have to be done by Sun
 Only base types need to be common
 Interfaces can evolve
 New apps can use new functionalities
 Old apps still work

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Network Technology
©2001KwangShinOH
Legacy Services
 Jini requires Java at the network
 Services identified by Java type
 Proxies may need code
downloaded
 Implementation can be non-Java
 Wrap legacy language in Java
 make calls to legacy with JNI

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Network Technology
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JiniTM
Roadmap
 JiniTM
Technology Starter Kit
 Version 1.0  Jan, 1999
 Version 1.0.1  Nov, 1999
 Version 1.1Alpha  Nov, 1999
 Version 1.1Beta  May, 2000
 Version 1.1  Oct, 2000

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Network Technology
©2001KwangShinOH
Reference
 JiniTM
Connection Technology
Architecture Overview
 Bill Day – Sun Microsystems
 JiniTM
Technology Core Platform
Specification Version 1.1
 October 2000 Sun Microsystems
 Core JINI – W.Keith Edwards
 1999 Prentice Hall

Jini Network Technology