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Java Technology for Internet Communications - PowerPoint

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									Java Technology for Internet Communications
Phelim O‟Doherty Software Architect Sun Microsystems

Mudumbai Ranganathan Computer Scientist National Institute of Standards and Technology (NIST)
| JavaOne 2003 | Session #1024

Overall Presentation Goal

Learn the technologies available for IP Communications networks that enable 3rd party application development.
B E G I N N I N G

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Speaker’s Qualifications
• Phelim O‟Doherty is a Internet Communications Technology Evangelist at Sun Microsystems.

• Phelim O‟Doherty is the specification lead for JSR 32 JAIN SIP and is an expert on JSR 116 SIP Servlet and JSR 180 SIP for J2ME. • Mudumbai Ranganathan is a Computer Scientist at NIST. • Mudumbai Ranganathan is the primary author of NISTSIP a public domain implementation of JSR 32 JAIN SIP and serves as an expert on JSR 125 and JSR 141.

B E G I N N I N G

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Fact

IP Communications will ‟NOT‟ be a remold of the old communications network, if ‟YOU‟ start implementing Java services that will run on the network.
B E G I N N I N G

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Presentation Agenda
• Overview of IP Communications • Java SIP Containers • SIP for J2ME • Overview of JAIN SIP • Conclusion
B E G I N N I N G

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IP Communications

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Evolution to IP Communications
Circuit-Switched
PR O PR I ET A RY

Soft-Switched
Services, Applications & Features (Management, Provisioning and Back Office) Open Applications APIs

Services & Applications Call Control & Switching Transport Hardware

Softswitch Call Control
Open Protocols APIs

Transport Hardware

• Solutions come from a single vendor that supplied everything in one proprietary box: software, hardware and applications • Customers are locked-in to their vendor—no room for innovation, expensive to implement and maintain
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• Solutions can come from multiple vendors, at all levels who supply open standards-based products • Customers are free to choose bestin-class products to build their network. Open standards enable innovation and reduce costs

Why Java and IP Communications?
JAVA Developer Base
Platform Indep.

Culture Open Interoperable Standard
Acceptance Momentum Flexible

IP Comm’s Internet model
Innovative Converged Services

Vendor Indep.

Scalable

Extensible

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Sample Network Architecture
SIP for J2ME Visited Network SIP Servlet PCSCF HSS OSA/OMA Node Core Network OSA/OMA Node

SIP for J2ME

JAIN SLEE

J2EE

Untrusted Network
MGCF

SIP Servlet
I-CSCF JAIN SIP SIP Servlet

JAIN SIP
S-CSCF

JAIN SLEE
Application Server

SIP for J2ME

JAIN SLEE

Application Server

MGW

Application Server
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Home Network

Varieties of IP Communications Containers
THIRD PARTY: Converged Services
Containers in yellow boxes
SIP App JSP App EJB App SLEE App

SIP Servlet HTTP Servlet

EJB

SLEE

SIP, Content-based Charging, Call Control, User Interaction, Messaging, Mobility

CORE NETWORK: Communications Services Call Control Servers, Proxy Servers, Location, Presence and Messaging
SLEE App SLEE App

SIP App

SIP App

SLEE INAP, TCAP, SIP

SIP Servlet SIP

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Why are Communications Applications Converging on Java Containers?
• Telco apps moving to component based architectures

• Desire to use Standard, Off-the-shelf container
– Write-once, run-anywhere

• Container provides important infrastructure services
– Higher level abstractions for State management, Transactions, Security, Resource pooling, …

• Focus on core value-add application logic • Leverage large community of Java developers • Leverage enterprise development tools, test suites, … • Time to market and reduced development cost
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Java SIP Containers

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SIP Execution Environments

SIP App
SIP Servlet

SIP App

SIP App

SIP App

EJB

JAIN SLEE

JAIN SIP JVM

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Application development options
Specification
JAIN SIP JAIN SIP & Connector
JAIN SIP & JAIN SLEE RA

Developer Community
Desktop Enterprise
Telecom

Target Java Platform
J2SE J2EE Business Tier
J2EE Business Tier

SIP Servlet
SIP for J2ME

Enterprise
Device

J2EE Web Tier
J2ME

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Realizing the SIP stack in Java

JCC

JAIN SLEE

Sipservlet

Industry Standard Interfaces

JAIN SIP
Dialog Layer Transaction Layer Message Layer
Proprietary Interfaces

SIP

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SIP in J2EE

SIP Servlet

JCA Connector

JAIN SIP

App Server

Application Server

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SIP EJB

App Server

JAIN SLEE
• JAIN SLEE is high performance event processing platform suitable for event driven applications.
– Supports simple and complex telecommunications applications. – Applications deal with service logic only.
• System issues handled by container i.e. threading, transactions

• Standard robust application framework and programming model.
– Object Orientated, asynchronous and distributable

• Independent of underlying networks. • Portable, robust and reusable applications. • Asynchronous support

– Elaborate event distribution mechanism (with priority) – Maps events to method invocations on components – Creates component instances in response to initial events

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JAIN SLEE Architecture
Management Application

JMX Agent

SLEE
Timer Facility

SLEE and Service Management Interfaces

Alarm Facility Trace Facility Usage Facility
Event Dispatcher

component instance component component instance instance component instance component instance

Component Container

JAIN SIP API

SIP based network

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SLEE Application Characteristics
Communications Enterprise

Invocations

Mostly asynchronous
•Events, messages, protocol triggers

Mostly synchronous invocations

•Mapped to method invocations

Components

Light-weight fine-grained objects

Short transient lifetimes
•Rapid creation, deletion

Heavy weight data access objects Long persistent lifetimes

Data Sources

Multiple data sources
•location, context information

Database servers
•Definitive master copy

•Provisioned data, cached from master copy

Back-end systems Database transactions
•Slower completion and less frequent

Transactions

Light-weight transactions
•For state replication demarcation

•Faster completion and more frequent

Computation

Compute-intensive
•Main input and output are resource invocations, messages, events

Database access intensive

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JAIN SLEE with JAIN SIP Resource
• JAIN SLEE represents network resources as resource adaptors and each resource adaptor has a type
– Resource adaptor type for JAIN SIP is „javax.sip‟

• JAIN SLEE identifies Event by Event types
– JAIN SIP Events are classified RequestEvents, ResponseEvents and TimeoutEvents, each of these classifications contains numerous types – For example the event type of a Request message of type „INVITE‟ is „javax.sip.RequestEvent.Request.INVITE‟

• JAIN SLEE represents the flow of events as activities
– Activity Objects in JAIN SIP are ClientTransactions (locally initiated) and ServerTransactions (remotely initiated)

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SIP Servlet
• SIP servlets typically reside on network servers where they will be responsible for making routing decisions.

• Supports RFC3261, RFC3262, RFC3265, RFC3428, and RFC2976 • Utilizes http servlet model as foundation, builds on http generic part for essential SIP request and response functionality • Allow applications to perform a fairly complete set of SIP signaling actions
– User agent client (UAC) – User agent server (UAS) – Proxy server
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SIP Servlet Goals
• Simplicity for the application developer
– Containers handle “non-essential” complexity such as managing network listening points, CSeq, Call-ID and Via headers, routes, etc. – Applications that span multiple protocols and media types, for example, Web, telephony, and presence. – An XML DD is used to communicate application information from the application developer to deployers. – Several applications can execute on the same incoming or outgoing request or response. Each application has its own set of rules and executes independently.

• Containers support converged applications • Third party application development: • Application composition:

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Extension to HTTP Servlet Model
• HTTP is not a peer-to-peer protocol like SIP therefore SIP Servlet extensions include:
– Initiate requests – Receive responses as well as requests – Generate multiple Responses • one or more 1xx followed by a final response – Proxying requests, possibly to multiple destinations

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Protocol and Application Sessions
• Sipservlet defines two types of sessions:
– SipSession (Protocol Session)
• Equivalent to HTTP Session and represents a Dialog in SIP

– SipApplicationSession
• Provides storage for application data • Enable different protocol sessions to share state i.e. HTTP and SIP • Defined by SIPServlet but is expected to be adopted by the Servlet specification in a future release.

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Message Hierarchy

ServletRequest

ServletResponse

javax.servlet

SipServletMessage javax.servlet.sip
SipServletRequest SipServletResponse

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SIP for J2ME

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Overview: SIP for J2ME
• SIP for J2ME is the standardised SIP interface for mobile handsets to communicate with core network functionality. • SIP for J2ME is an optional package for the J2ME platform that enable resource limited devices to send and receive SIP messages
• The specific is designed for the CLDC profile, however it can also be used on to the CDC profile also.

• The specification gives the developer transactional control over the SIP protocol • Client devices must support SIP for Rel5.0 of the UMTS architecture. SIP for J2ME is the perfect platform for these client devices.
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SIP for J2ME Goals
• Enables terminals supporting CLDC to run SIP enabled MIDlets • Builds upon CLDC Generic Connection framework • Specifically targeted at mobile phone handsets • Keep the “look and feel” of the HTTP API • Keep the API size small - keep the number of created objects low • Provide developers with helper functions
– RefreshHelper for Register and Subscribe

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SIP and the Generic Connection Framework

Connection

SipConnection

SipConnection Notifier

InputConnection

OutputConnection

DatagramConnection

SipClientConnection

StreamConnection SipServerConnection
ContentConnection

HttpConnection

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SIP for J2ME Architecture

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Other SIP and IM Interfaces & J2ME

MIDP

JAIN SIMPLE

SIP for J2ME

JAIN PIM

CLDC KVM

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JAIN SIP

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Overview: JAIN SIP
• Java-standard interface to a SIP signaling stack.
– Standardized the interface to the stack. – Standardized the events and event semantics. – Application portability - verified via the TCK.

• Designed for the developer who requires powerful access to the SIP protocol.
• JAIN SIP can be utilized in a user agent, proxy, or imbedded into a service container. • Supported RFCs:
– RFC 3261, 2976, 3262, – RFC 3265, 3311, 3428

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JAIN SIP Architecture
Application

Listener

Listener SIP Events SIP Messages
SIP Events

SIP Messages Provider

Provider Listening Point Stack Network

Listening Point
Stack

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Responsibilities of the Application
• Application registers an implementation of the SipListener interface to interact with the SIP Stack • Application MUST go via the SipProvider for all messaging with the stack – Application Sends messages and access stack objects via the SipProvider. • Application receives messages from the stack as Events via the SipListener interface.

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Services provided by JAIN SIP
• Provide methods to format and send SIP messages
• Parse incoming messages and enable application to access to fields via a standardized JAVA interface. • Invoke appropriate application handlers when protocol significant (message arrivals, Transaction time-outs) • Provide Transaction support and manage Transaction state and lifetime on behalf of a user application.

• Provide Dialog support and manage Dialog state and lifetime on behalf on a user application.

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SIP Transactions
SIP transaction consists of a single request and any responses to that request.
Server transaction Server transaction Client transaction

UAC
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Client transaction

Stateful proxy

UAS

Transaction Support
• Transaction is created on incoming Request or may be created to send outgoing request.
– When a Request is sent out statefully, application must request a ClientTransaction for the outgoing Request. – When a new Request arrives, Stack associates a ServerTransaction with Request and passes up to application.

• When a response arrives, the Stack possibly associates a previously created ClientTransaction with the response and passes up to the Application.
• The JAIN SIP implementation manages the association between Transactions and Dialogs.
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Support for Dialogs
• A Dialog is a peer to peer association between communicating SIP endpoints.
– Maintains Route Sets and Sequence Numbers.

• Dialogs are never directly created by the Application.. – Dialogs are established by Dialog creating Transactions (INVITE, MESSAGE, SUBSCRIBE…), however are managed by the stack.
• Dialog deletion may be under application control. • Transactions may belong to a Dialog – Dialog state changes as a result of changes in Transaction State
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Addresses, Messaging and Headers
• Defines support for Address/Header/Message Factories.
• Address package contains a URI wrapper and defines URIs for SIP and Tel URIs. • Header package defines interfaces for all the supported headers. • Accessor (set/get) methods for SIP Header parameters. • Deep copy requirement for cloning Addresses, Headers and Messages for the benefit of proxies.
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SipStack Interface
• Manages Listening Points and Providers. • SipStack associated with an IP address.
─ Can Have multiple Listening points.

• Application can have multiple SipStacks. • Cannot be deleted once created.
• Instantiated by the SipFactory and initialized with a Property set.

• javax.sip.* properties are reserved and names defined for stack configuration properties.
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SipProvider Interface
• Send Request's either statefully via client transactions or statelessly. • Send Response's to a recently received Requests either statefully via server transactions or statelessly. • Register a SipListener to the SipProvider.
– Notifies Registered Listener of Events (Request/Response/Timeout).

• De-register a SipListener from the SipProvider.
– Once de-registered, no longer receive Events from SipProvider.

• New Client and Server Transaction methods. • Listening Point manipulation methods.
– Only one provider per listening point.
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SipListener Interface
• A single SipListener per SipStack which implies a single Listener in the architecture
– all SipProviders associated to a Sipstack have the same SipListener.

• Process Request's either statefully or statelessly dependent on application. • Process Response's to a recently sent Requests statefully. • Process Transaction timeouts and retransmits Timer events.

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Application - Stack Creation
Initialize Stack using SipFactory:
try { Properties properties = new Properties(); properties.setProperty("javax.sip.IP_ADDRESS", "129.6.55.181"); properties.setProperty("javax.sip.OUTBOUND_PROXY", "129.6.55.182:5070/UDP"); ……// Other initialization properties. try {
sipStack = sipFactory.createSipStack(properties);

} catch(SipException e) { System.exit(-1); }
}

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Application – Request Creation
Initialize Request using Factories:
try { SipURI requestURI = addressFactory.createSipURI (toUser, toSipAddress); // … Create other headers Request request = messageFactory.createRequest (requestURI, Request.INVITE, callIdHeader, cSeqHeader, fromHeader, toHeader, viaHeaders, maxForwards); }

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Application - Sending Requests
Send outgoing messages:
try { // Create the client transaction ClientTransaction inviteTid = sipProvider.getNewClientTransaction(request); // send the request sipProvider.sendRequest(inviteTid,request); }

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Application – Processing Requests
Handle incoming messages as Events:
try { public void processRequest(RequestEvent requestEvent) { Request request = requestReceivedEvent.getRequest(); ServerTransaction st = requestEvent.getTransaction(); // do request specific processing here } }

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JAIN SIP for Instant Messaging
• JAIN SIP can be used for building Instant Messaging and Presence Clients and Servers. • API supports the required methods and Headers.
• JAIN creates and manages Dialogs for SUBSCRIBE and MESSAGE methods. • NIST-SIP JAIN IM Client SipListener is about 1100 LOC.

• Interoperates with Microsoft IM and packaged with RI as example.

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JAIN-SIP in Proxy Servers
• JAIN SIP facilities construction of Proxy Servers: • Stateless, Transaction-stateful, and Dialog-stateful operation. • Application has access to Dialog/Transaction state and route tables. • Support for extensibility and application- controlled Routing. • Deep copy semantics for cloning. • Example Proxy (including presence server) is about 3500 LOC and is included with RI.

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JAIN SIP Extensibility
• SIP Extensions Typically Define:
– New Methods – New Headers – New Dialog Creating Methods

• JAIN SIP Supports these by:
– Architected ExtensionHeader that can be created/accessed by name. – New Dialog Creating methods specified at Stack configuration via configuration property.

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JAIN SIP Updates
JAIN SIP v1.0
• RFC2543 Supported.

JAIN SIP v1.1
• RFC3261 Supported.

• J2SE 1.3 and above. • Transactions referenced by long. • Transaction state is not visible to application.
• No explicit Dialog Support.

• J2SE 1.4 and above. • Transaction interfaces defined. • Transaction/Dialog state can be read by application.
• Dialog interface defined and managed by stack.

• Stack Configuration not defined.

• Stack Configured with defined properties.

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JAIN SIP Reference Implementation
• In the public domain. – Includes example IM client and proxy. – Includes trace visualization tools. • Footprint – About 46000 LOC. – Jar file about 355 Kb (not counting JAIN API). – About 3 Megabytes of memory after class loading and running a few requests. http://www-x.antd.nist.gov/proj/iptel
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Useful URLs
• JAIN SIP Specification: http://jcp.org/jsr/detail/032.jsp • NIST IP-Telephony Project Page: http://www-x.antd.nist.gov/proj/iptel/index.html • JAIN SIP Discussion List: http://archives.java.sun.com/jain-sip-interest.html • JAIN Homepage: http://java.sun.com/products/jain

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Conclusion

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Other Java API’s for IP Communications
• JAIN Presence and IM - Panasonic • JAIN SIMPLE – Panasonic • JAIN SIP Lite - Ubiquity • JAIN Enum – NetNumber
• JAIN MGCP – Telcordia • JAIN Megaco – Hughes Software Systems • JAIN SDP – dynamicsoft http://jcp.org/en/jsr/tech?listBy=2&listByType=tech
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Summary
• IP Communications is the crux of NGN‟s, investment and converged applications. • Java and IP Communications together enable a developers working environment.
– You can develop services today with an open source SIP stack supporting standardized Java API‟s.

• The Internet and communications networks will converge, Java developers will capitalize.
E N D

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If You Only Remember One Thing…
Communications is the „Killer App‟. IP Communications & Java lets you „play‟!
Internet – EMail – IM • The Mobile Phone – SMS - MMS • …….. What‟s next? • The possibilities are endless!
• The

E N D

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Q&A


								
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