Java Technology for Internet Communications

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Java Technology for Internet Communications

• Phelim ODoherty
• Software ArchitectSun Microsystems

Mudumbai Ranganathan Computer Scientist National
Institute of Standards and Technology (NIST)
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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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Speakers Qualifications

• Phelim ODoherty is a Internet Communications
  Technology Evangelist at Sun Microsystems.
• Phelim ODoherty 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 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
PROPRIETARY
Services Applications
Call Control Switching
TransportHardware

• Solutions come from a single vendor that supplied
  everything in one proprietary box software,
  hardware and applications
• Customers are locked-in to their vendorno room
  for innovation, expensive to implement and
  maintain

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Why Java and IP Communications?
IP Comms
JAVA
Developer Base Platform Indep.
Vendor Indep.
Culture Open Interoperable Standard Acceptance Mo
mentum Flexible Extensible
Internet model Innovative
Converged Services Scalable

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Sample Network Architecture
SIP for J2ME
SIP for J2ME
J2EE
JAIN SLEE
Visited Network
SIP Servlet
OSA/OMA Node
OSA/OMA Node
P-CSCF
Core Network
Untrusted Network
HSS
JAIN SIP
SIP Servlet
MGCF
S-CSCF
I-CSCF
SIP Servlet
JAIN SIP
JAIN SLEE
JAIN SLEE
ApplicationServer
SIP for J2ME
MGW
ApplicationServer
ApplicationServer
Home Network
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Varieties of IP Communications Containers
THIRD PARTY Converged Services
SLEE App
JSP App
EJB App
SIP App
Containers in yellow boxes
SLEE
EJB
HTTP Servlet
SIP Servlet
SIP, Content-based Charging, Call Control, User
Interaction, Messaging, Mobility
CORE NETWORK Communications Services Call
Control Servers, Proxy Servers, Location,
Presence and Messaging
SIP App
SIP App
SLEE App
SLEE App
SLEE
SIP Servlet
INAP, TCAP, SIP
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 App
SIP App
SIP Servlet
EJB
JAIN SLEE
SIP App
JAIN SIP
JVM
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Application development options
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
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Realizing the SIP stack in Java
JAIN SLEE
Sipservlet
JCC
Industry Standard Interfaces
Dialog Layer
Proprietary Interfaces
Transaction Layer
Message Layer
SIP
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SIP in J2EE
SIP Servlet
JCA Connector
JAIN SIP
App Server
App Server
SIP EJB
Application Server
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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
SLEE
Component Container
JMX Agent
component instance
Timer Facility
component instance
component instance
Alarm Facility
SLEE and Service Management Interfaces
component instance
Trace Facility
component instance
Usage Facility
Event Dispatcher
JAIN SIP API
SIP based network
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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
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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.Reques
  t.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.
• 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.

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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
SipServletResponse
SipServletRequest
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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
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SIP for J2ME Architecture
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Other SIP and IM Interfaces J2ME
JAIN SIMPLE
SIP forJ2ME
MIDP
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 Messages
SIP Events
SIP Messages
SIP Events
Provider
Provider
Listening Point
Listening Point
Stack
Stack
Network
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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
Client transaction
Stateful proxy
UAC
UAS
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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",
"129.6.55.1825070/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.createS
ipURI (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 ClientTr
ansaction inviteTid sipProvider.getNewClientTra
nsaction(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.getTrans
action() // 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
JAIN SIP v1.1

• 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.

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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.su
  n.com/jain-sip-interest.html
• JAIN Homepagehttp//java.sun.com/products/jain

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Conclusion
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Other Java APIs 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?listBy2listByTypetec
h
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Summary

• IP Communications is the crux of NGNs,
  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
  APIs.
• The Internet and communications networks will
  converge, Java developers will capitalize.

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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
• .. Whats next?
• The possibilities are endless!

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QA
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