| JavaOne 2003 | Session #1024 Java Technology for Internet Communications Phelim O’Doherty Software Architect Sun Microsystems Mudumbai Ranganathan Computer

| JavaOne 2003 | Session #1024

Java Technology for Internet Communications

Phelim O’Doherty

Software ArchitectSun Microsystems

Mudumbai Ranganathan

Computer Scientist

National Institute of Standards and Technology (NIST)

| JavaOne 2003 | Session #1024 2

Overall Presentation Goal

BEGINNING

Learn the technologies available for IP Communications networks that enable 3rd party application development.


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 NIST-SIP a public domain implementation of JSR 32 JAIN SIP and serves as an expert on JSR 125 and JSR 141. B

EGINNING


IP Communications will ’NOT’ be a remold of the old communications network, if ’YOU’ start implementing Java services that will run on the network.

BEGINNING

Fact


Presentation Agenda

• Overview of IP Communications

• Java SIP Containers

• SIP for J2ME

• Overview of JAIN SIP

• ConclusionBEGINNING


IP Communications


Evolution to IP Communications

PRO

PRI

ETA

RY

• 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

Circuit-Switched

• Solutions can come from multiple vendors, at all levels who supply open standards-based products

• Customers are free to choose best-in-class products to build their network. Open standards enable innovation and reduce costs

Soft-Switched

Transport Hardware

Softswitch Call Control

Services, Applications & Features (Management, Provisioning and

Back Office)

Open Applications APIs

Open Protocols APIsTransportHardware

Call Control & Switching

Services & Applications


Why Java and IP Communications?

Culture

Open

Interoperable

Standard

Acceptance

Momentum

Flexible

Extensible

Developer Base

Platform Indep.

Vendor Indep.

Internet model

Innovative Converged Services

Scalable

JAVAIP Comm’s


S-CSCFMGCF

MGW

HSS

ApplicationServer

SIP for J2ME

JAIN SIP

SIP for J2ME

JAIN SIP

SIP for J2ME

SIP Servlet

JAIN SLEE

SIP ServletJAIN SLEE

I-CSCF

Core Network

Visited Network

P-CSCF

SIP Servlet

ApplicationServer

Home Network

ApplicationServer

Sample Network Architecture

Untrusted Network

OSA/OMANode

OSA/OMA Node

J2EEJAIN SLEE


Varieties of IP Communications Containers

SLEE

SLEE App

EJB

JSP App EJB App

HTTP ServletSIP Servlet

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

SIP App

SLEE

INAP, TCAP, SIP

SLEE App SLEE App

SIP Servlet

SIP

SIP App SIP App

CORE NETWORK: Communications ServicesCORE NETWORK: Communications ServicesCall Control Servers, Proxy Servers,Call Control Servers, Proxy Servers,Location, Presence and MessagingLocation, Presence and Messaging

THIRD PARTY: Converged ServicesTHIRD PARTY: Converged Services

Containers in yellow boxes


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


Java SIP Containers


SIP Execution Environments

JAIN SIP

SIP Servlet

EJB

JVM

JAIN SLEESIP App

SIP App SIP AppSIP App


Specification Developer Community Target Java Platform

JAIN SIP Desktop J2SE

JAIN SIP & Connector Enterprise J2EE Business Tier

JAIN SIP & JAIN SLEE RA Telecom J2EE Business Tier

SIP Servlet Enterprise J2EE Web Tier

SIP for J2ME Device J2ME

Application development options


Realizing the SIP stack in Java

SIP

Packet Network

Message Layer

Transaction Layer

Dialog Layer

JAIN SIP

JCC JAIN SLEE Sipservlet Industry StandardInterfaces

ProprietaryInterfaces


SIP in J2EE

JCA

Con

nec

tor

SIP

Ser

vlet

SIP

EJB JA

IN S

IP

Ap

p S

erve

r

Ap

p S

erve

r

Application 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


JAIN SLEE Architecture

Management Application

SIP based network

SLEE ComponentContainer

componentinstance

componentinstance

componentinstance

componentinstance

componentinstance

JMX Agent

Trace Facility

Timer Facility

Alarm Facility

Usage Facility

JAIN SIP API

Event Dispatcher

SLEE and ServiceManagement

Interfaces


SLEE Application Characteristics

Communications Enterprise

Invocations Mostly asynchronous•Events, messages, protocol triggers

•Mapped to method invocations

Mostly synchronous 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

•Provisioned data, cached from master copy

Database servers•Definitive master copy

Back-end systems

Transactions Light-weight transactions•For state replication demarcation

•Faster completion and more frequent

Database transactions•Slower completion and less frequent

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

Database access intensive


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)


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


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.

• Containers support converged applications – Applications that span multiple protocols and media

types, for example, Web, telephony, and presence.

• Third party application development: – An XML DD is used to communicate application

information from the application developer to deployers.

• Application composition: – Several applications can execute on the same incoming

or outgoing request or response. Each application has its own set of rules and executes independently.


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


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.


Message Hierarchy

SipServletResponseSipServletRequest

SipServletMessage

ServletRequest ServletResponse javax.servlet

javax.servlet.sip


SIP for J2ME


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.


• 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

SIP for J2ME Goals


SIP and the Generic Connection Framework

Connection

InputConnection OutputConnectionSipConnection DatagramConnection

StreamConnection

ContentConnection

HttpConnection

SipConnectionNotifier

SipClientConnection

SipServerConnection


SIP for J2ME Architecture


MIDP

CLDC

JAIN SIMPLE

KVM

Other SIP and IM Interfaces & J2ME

SIP forJ2ME

JAINPIM


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

Overview: JAIN SIP


JAIN SIP Architecture

Listener

Provider Provider

Stack Stack

Listener

Network

SIP Events SIP EventsSIP Messages SIP Messages

Application

Listening Point Listening Point


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.


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.


SIP Transactions

Server tran

saction

Clien

t transaction

Clien

t transaction

Server tran

saction

Stateful proxyUAC UAS

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


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.


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


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.


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.


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.


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.


Application - Stack Creation

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); }}

Initialize Stack using SipFactory:


Application – Request Creation

try {

SipURI requestURI = addressFactory.createSipURI

(toUser, toSipAddress);

// … Create other headers

Request request = messageFactory.createRequest

(requestURI, Request.INVITE, callIdHeader, cSeqHeader, fromHeader, toHeader,

viaHeaders, maxForwards);

}

Initialize Request using Factories:


Application - Sending Requests

try {

// Create the client transaction

ClientTransaction inviteTid = sipProvider.getNewClientTransaction(request);

// send the request

sipProvider.sendRequest(inviteTid,request);

}

Send outgoing messages:


Application – Processing Requests

try {

public void processRequest(RequestEvent requestEvent) {

Request request = requestReceivedEvent.getRequest();

ServerTransaction st =

requestEvent.getTransaction();

// do request specific processing here

}

}

Handle incoming messages as Events:


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.


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.


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.


JAIN SIP Updates

• RFC2543 Supported.

• J2SE 1.3 and above.

• Transactions referenced by long.

• Transaction state is not visible to application.

• No explicit Dialog Support.

• Stack Configuration not defined.

• RFC3261 Supported.

• J2SE 1.4 and above.

• Transaction interfaces defined.

• Transaction/Dialog state can be read by application.

• Dialog interface defined and managed by stack.

• Stack Configured with defined properties.

JAIN SIP v1.0 JAIN SIP v1.1


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


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


Conclusion


• 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

Other Java API’s for IP Communications

http://jcp.org/en/jsr/tech?listBy=2&listByType=tech


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.

END


If You Only Remember One Thing…

Communications is the ‘Killer App’. IP Communications & Java lets you ‘play’!

• The Internet – EMail – IM • The Mobile Phone – SMS - MMS • …….. What’s next?• The possibilities are endless!

END

Q&A

Documents

| JavaOne 2003 | Session #1024 Java Technology for Internet Communications Phelim O’Doherty Software Architect Sun Microsystems Mudumbai Ranganathan Computer