iBus Ein Software Bus fr Java Komponenten

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iBus - Ein Software Bus für Java Komponenten

• Dr. Silvano Maffeis
• SoftWired AG, Zürich
• maffeis_at_softwired.ch

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Trends

• The Real-Time Enterprise
• Competitive advantage by increasing speed of
  business activity
• Immediately process changes in information
• Componentware
• Distributed information systems, software
  composition
• JavaBeans, ActiveX, CORBA
• Ubiquitous computing
• Intelligent watches, mobile phones, PDAs, home
  appliances
• Exchange events via infrared, satellite and
  cellular channels

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Need Middleware which is ...

• Component based
• Platform independent
• Light-weight
• Flexible and event-oriented
• Extensible at development-time and at run-time
  (!)
• Pure Java Software Bus

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Works like Radio Transmission...
Station A
Station B
The Ether
Radio Channels
Tuner 2
Tuner 1
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Publish/Subscribe Communication
subscribe (SUN) subscribe (AAPL)
subscribe (SUN)
publish (AAPL, 29.2) publish(AAPL, 29.3)
Intranet
subscribe (AAPL) subscribe (SUN) publish(SU
N, 43.0) publish(SUN, 42.7)
subscribe (AAPL)
subscribe (AAPL) subscribe (SUN)
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Differences to CORBA and RMI

• Group communication vs. point-to-point
• Channel subscription vs. resolving references
• Spontaneous networking, plug-and-play
• Self-describing event objects vs. static IDL
  interfaces
• Lose coupling, no import of IDL interfaces
• Software medium abstraction

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Hub-and-Spoke Architecture

• Employs a network centric broker application
• All events are passed through the broker

TCP
TCP

• Maintains subscriptions
• Distributes events

Broker
TCP
TCP
TCP
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Multicast Bus Architecture

• A fully distributed and scalable architecture
• No broker processes
• Events are transmitted by IP multicast

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IP Multicast Details

• IEEE 802 LANs (Ethernet, Token Ring, FDDI)
  support multicast and broadcast
• A low-level software bus
• Most efficient dissemination of information
• IP Multicast uses hardware multicast
• Class D IP addresses (224.0.0.0 to
  239.255.255.255)
• 11 mapping into Ethernet addresses

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IP Multicast Example
mrouted 130.80.51.1 130.80.52.1
send (datagram, 226.1.1.1) 130.80.51.10
IGMP
IGMP
Subnet 130.80.51.0
Subnet 130.80.52.0
recv (226.1.1.1) 130.80.51.12
recv (226.1.1.1) 130.80.51.11
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Products

• Iona OrbixTalk (www.iona.com) (C, multicast)
• TIBCO ObjectBus (www.tibco.com) (C, multicast)
• Talarian SmartSockets (www.talarian.com) (C,
  hs)
• VisiBroker Events (www.inprise.com) (Java, hs)
• Marimba Castanet (www.marimba.com) (Java, hs)
• iBus (www.softwired.ch) (Java, multicast)

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SoftWired iBus

• Combines the advantages of Java and of the
  Software Bus model
• Multicast Bus architecture fully distributed
• Hub-and-spoke also supported
• Extensible TCP, IP Multicast, encryption,
  compression,
• Light-weight 100k library, 300k heap space

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What You Get

• iBus consists of a programming library (JAR file)
  and of utility applications
• The library provides classes and methods to
• Open communication channels for transmission
• Subscribe an interest in communication channels
• Pushing events (Java objects) into channels
• Pulling events through channels (like RMI)
• Track failures
• Installation
• Copy iBus JAR file
• Set CLASSPATH variable and go!
• java iBus.util.talker

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iBus Channels and URLs

• Channels are named by iBus URLs such as
• ibus//226.1.1.1/financial/quotes/SUN
• ibus//pluto.sun.com/updates/jdk
• Both reliable IP multicast and TCP channels
• Multicast used mainly inside Intranets
• (Secure) TCP channels can be established for
  routing iBus events between Intranets

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Protocol Stack Framework

• iBus API separate from transport layers
• Other middleware products are black boxes
• iBus Protocol Stack framework to
• customize of retransmission delays etc.
• add new communication protocols (e.g., infrared,
  satellite)
• include new quality of services (e.g., special
  purpose encryption, different reliable multicast
  protocols)
• Gray Box approach

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Protocol Stack Framework (cont.)
Receiver Objects
Receiver Objects
FIFO
ZIP
Protocol Stack
Protocol Stack
NAK
REACH
CONTEXT
...
IPMCAST
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Sample Talker Application
import iBus. public class Talker public
static void main (String argv) throws
Exception // create an iBus protocol
stack for reliable multicast Stack stack
new Stack (Reliable") // create an
iBus URL for the destination channel
iBusURL url new iBusURL ("ibus//226.1.2.3/finan
cial/quotes") // open the channel
stack.registerTalker(url) // create
a Posting to hold a quote string Posting
posting new Posting ()
posting.setLength(1) posting.setObject(0,
new String(SUN 42.7)) // multicast
the quote through the iBus channel denoted by
url stack.push (url, posting)
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Sample Listener Application
import iBus. // The listener
application public class Listener public
static void main (String argv) throws
Exception Stack stack new Stack
(Reliable") QuoteReceiver
receiverObject new QuoteReceiver ()
iBusURL url new iBusURL ("ibus//226.1.2.3/finan
cial/quotes") stack.subscribe (url,
receiverObject) stack.waitTillExit()
// A listener class to receive
quotes class QuoteReceiver implements
iBus.Receiver public void dispatchPush
(iBusURL source, Posting p) // to
display the quote string
System.out.println ("QuoteReceiver got a quote
" (String) p.getObject(0))
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Distributed Information Systems
WallStreetWeb
Event Producer
Event Producer
iBus Gateway
Filter
Filter
iBus Software Medium
Event Consumer
Event Consumer
Gateway
Gateway
Gateway
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Stand-alone Applications
iBus Software Medium
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Vehicle Communication System
Maps etc.
Naming
iBus Software Medium
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iBus Status

• Core product of SoftWired AG
• Public review releases since early 1997
• Tested on NT, Win95, Solaris, Linux, (AIX)
• Projects (Financial) information systems,
  multimedia
• Technical support and consulting services
• Software at http//www.softwired.ch/ibus

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Summary

• Trends the real-time enterprise, componentware,
  ubiquitous computing, ...
• Need A software medium
• Software bus advantages
• Technical fault-tolerance, efficient
  dissemination of events, spontaneous networking
  (like JINI)
• Design lose coupling of components, flat
  architectures, extensibility and maintainability
• iBus Combines the advantages of software buses,
  Java, and of protocol composition