® ibm software group © 2007 ibm corporation introduction to sip in websphere erik burckart...

®

IBM Software Group

© 2007 IBM Corporation

Introduction to SIP in WebSphere

Erik Burckart

WebSphere Architect

IBM Software Group | WebSphere software

2

What is SIP?

Session Initiation Protocol Negotiate a session between two users or services, often utilizing a different

protocol.

Often used for peer to peer models.

Control protocol for many types of new communications Voice over IP (VoIP)

Instant Messaging (IM)

Pivotal protocol in building the next generation telecommunications networks


3

Sarah dials Todd

Trying

Ringing

OK

ACK

Telephone Network

INVITE Todd

Todd picks up

Hello Sarah?

Hi Todd!

How does SIP work?


4

More on SIP… A SIP URL looks like an email address

SIP:[email protected] SIP:[email protected];user=phone

TEL URLs are also used TEL:+1-919-555-1234

Since SIP is used to initiate another session, the popular protocol used to describe that session is called Session Description Protocol (SDP, defined in RFC 2327

Helpful terminology… A Dialog is a peer to peer relationship between

two user agents (SIP nodes) A User Agent Client (UAC) creates a request or

dialog A User Agent Server (UAS) handles a request or

dialog A Back to Back User Agent (B2BUA) is

UAS/UAC combination that handles completes the incoming call and creates another identical one.

A proxy is a stateful server which forwards on the request to another user agent to handle.


5

Proxy

server.telco2.com

Proxy

proxy.telco1.comUser Agent

[email protected]

User Agent

[email protected]

INVITEINVITE

INVITE100 TRYING

100 TRYING

180 RINGING

180 RINGING

180 RINGING 200 OK200 OK

200 OK

ACK

200 OK

BYE

Media Session


6

Sarah dials Todd

SIP/2.0 180 RingingRoute: <sip:s1.telco.com>From: Sarah <sip:[email protected]>To: Todd <sip:[email protected]>Call-ID: abc123CSeq: 1 INVITEContact: <sip:[email protected]>

SIP/2.0 200 OKRoute: <sip:s1.telco.com>From: Sarah <sip:[email protected]>To: Todd <sip:[email protected]>Call-ID: abc123CSeq: 1 INVITEContact: <sip:[email protected]>

ACK sip:[email protected] SIP/2.0Route: <sip:s1.telco.com>From: Sarah <sip:[email protected]>To: Todd <sip:[email protected]>Call-ID: abc123CSeq: 1 ACK

Telephone Network

INVITE sip:[email protected] SIP/2.0Route: <sip:s1.telco.com>From: Sarah <sip:[email protected]>To: Todd <sip:[email protected]>Call-ID: abc123CSeq: 1 INVITEContact: <sip:[email protected]>

Todd picks up

Hello Sarah?

Hi Todd!

More in depth details…

Negotiated Media Session


7

What can I do with SIP?

Utilize SIP environments VoIP IM IPTV Audio/Video conferencing. Next generation Telco networks.

Embed intelligent communications in applications Improve Business Productivity

Click to call, IM Manage calls on the web

– Caller ID information

– Three way calling, voicemail, etc. Integrate with Business Processes

Automatically generated phone calls in a workflow.


8

Examples of Other Potential Applications Business Conferencing

Mobile Conferencing

Virtual Receptionist

Prepaid Calling Cards

Push to Talk over Cellular (PoC)

Voice with Push to See

Voice with Push to Video

Voice with push of Media Mapping services

Converged mobility WiFi to GSM roaming

White Boarding (sharing)

Field Force Efficiency

Field Force Automation

Fleet Management & Logistics

Multimedia messaging with email, fax, voice mail, video mail, IM notification

IM with multimedia

Presence based applications

Interactive Gaming

Text, Picture and Voice Messaging

Subscription Media Push

Video on demand to mobile phone

Personalized call tones

Inbound call screening

Friends & Family Tracking

Security/Medical Monitoring


9

Why IBM?

IBM’s vision is that intelligent communications can be embedded in all applications.

IBM has been utilizing SIP since 2000.

WebSphere Application Server is the first vendor to include SIP in their base Java EE environment, allowing all applications to utilize SIP.

IBM has many products utilizing SIP WebSphere Application Server WebSphere Presence Server (with Group List management) WebSphere IP Multimedia Subsystem Connectors WebSphere Telecom Web Services Server Lotus Sametime Gateway WebSphere Voice Server WebSphere Voice Response More to come…


10

WebSphere SIP

SIP Servlet 1.0 API JSR 116

Built into the Servlet container that also hosts Portlets and HTTP Servlets.

IBM Extensions to SIP and HTTP session to provide fully converged functionality.

SIP Servlet tooling Wizards

Graphical Deployment Descriptor Editors


11

WebSphere Proxy with SIP

High availability that understands applications which include SIP and HTTP.

Converged Proxy server HTTP Reverse Proxy

Stateless SIP Proxy

Routes messages to keep SIP and HTTP Sessions in a single Application Session together.


12

SIP Servlet 1.0 vs HTTP Servlets Asynchronous instead of synchronous.

Servlet has methods for the requests and responses separately.

Multiple servlets can act on a single message

Stateful proxying APIs.

Application can be UAC, UAS, B2BUA, or Proxy.

Provides SipFactory per application for creating requests, sessions, etc.

SipSession and SipApplicationSession

IBM provides useful extensions to the specifications

doGetdoPostdoPut

doHeaddoDeletedoTrace

doOptions

HTTP Servlet

doInvitedoAck

doOptionsdoBye

doCanceldoRegister

doSubscrbedoNotify

doMessagedoInfo

doPrack

SIP Servletrequests

doProvisionalResponsedoSuccessResponsedoRedirectResponse

doErrorResponse

SIP Servlet responses

HttpSession SipSession

SipApplicationSession

IBMSession

IBMApplicationSession

extends

extends

containscontains

references

references


13

SIP Servlet 1.0 API – JSR 116

destroy()

service()

init()

doInvite() doAck()

doOptions() doCancel()

doRegister() doPrack() doInfo()

doNotify() doMessage() doSubscribe()

doProvisionalResponse() doSuccessResponse()

doErrorResponse() doRedirectResponse()

doResponse()

doRequest()

servlet

Create Request()

Create Response()

SIP Message

Client SIP Container SIP Servlet Methods

RulesSIP Message


14

SIP Servlet 1.1 API – JSR 289

Application Router functionality Allows the Deployer to add functionality to dynamically

select which Servlets will be executed.

Spans multiple applications and there will be one per server.

Better support for convergence Session convergence like the WebSphere 6.1 model.

More flexible ways to get to the SipFactory within an application.

Alignment with Java EE 5 Alignment with Servlet 2.5 specification

Annotations support

Utilizes JSR 250 and the Servlet 2.5 specification

Adds Type level annotations like @SipServlet.

Resource injection where appropriate, like accessing the SipFactory

Application Router S

IP A

pp

licat

ion

SIP Servlet API

WebSphere Servlet Container

SIP

Ap

plic

atio

n

SIP

Ap

plic

atio

n

SIP

Ap

plic

atio

n

SIP HTTP


15

Example: Caller ID in a web page

Include information about incoming callers on existing Portals. Could include looking up customer records, LDAP, etc.

Works with SIP network, but does not require SIP phones.

SIP Servlet

JMS Topic HTTP Servlet

IP PBXPSTN

SIP Proxy

Initiate Call

Publish call info

Subscribe to a topic Poll the server for caller ID

Send caller ID


16

Example: Click to call in a webpage Make every phone number a clickable link.

Could include call status

Helps efficiency by ensuring phone numbers are not mistyped.


Another option below is that the HTTP Servlet can look at the information in the SIP Session since they are tied together

SIP Servlet

JMS Topic HTTP Servlet

IP PBXPSTN

SIP Proxy

Publish call status

Subscribe to a topic Request a call be made

Send status

Make call

Make call

Poll for status


17

Example: Click to call with expert routing Make asking for help a clickable link

Allows an expert to be chosen from a group


Another option below is that the HTTP Servlet can look at the information in the SIP Session since they are tied together

Group List server

IP PBX SIP Proxy

PSTN

Presence Server

HTTP

SIP

Request Help

Find experts Find availabilityOf experts

Fetch help context

Make call Make call

Acceptcall

Acceptcall

ExpertCustomer


18

Quick code example, click to call

sipFactory =(SipFactory)getServletContext().getAttribute(SipServlet.SIP_FACTORY);

SipURI uriFrom = (SipURI) sipFactory.createURI(from);SipURI uriTo = (SipURI) sipFactory.createURI(to);SipServletRequest req =

sipFactory.createRequest(appSession, "INVITE", uriFrom, uriTo);req.setRequestURI(uriTo);req.send();

SipURI uriFrom = (SipURI) sipFactory.createURI(previousTo);SipURI uriTo = (SipURI) sipFactory.createURI(previousFrom);SipServletRequest req =

sipFactory.createRequest(appSession, "INVITE", uriFrom, uriTo);req.setRequestURI(uriTo);req.send();

Create a call to from the first side. This can be called from the HTTP Servlet by fetching the SipFactory from the Servlet Context.

After the first invitation comes back successful, create a call to the other side with the To and From flipped. This can be added in the doSuccessResponse method of the SipServlet.


19

Questions?

References Introducing SIP Articlehttp://www-128.ibm.com/developerworks/websphere/techjournal/0606_burckart/0606_burckart.html

Developing Converged Applications Articlehttp://www-128.ibm.com/developerworks/websphere/techjournal/0608_burckart/0608_burckart.html

Developing SIP and IP Multimedia Subsystem Applications Redbookhttp://www.redbooks.ibm.com/redbooks.nsf/e9abd4a2a3406a7f852569de005c909f/4ccb6d54f16a5a2f85257134005468db?OpenDocument

WebSphere Application Server SIP documentationhttp://publib.boulder.ibm.com/infocenter/wasinfo/v6r1/index.jsp?topic=/com.ibm.websphere.nd.doc/info/ae/ae/welc6tech_sip_links.html


20

BACKUP


21

Architecture Converged Container

Seamless integration between JSR 116 SIP Servlets and HTTP Servlets or Portlets. Built on proven WebSphere technology.

Converged Proxy Ensures single point of session affinity management at the application session level, across

HTTP and SIP Provides high availability without expensive hardware.

Servlet ContainerServlets, SIP Servlets, Portlets

Proxy ServerStateless SIP Proxy and HTTP reverse proxy


22

Specifications – What WAS SIP SupportsBody Number Title

JCP JSR 116 SIP Servlet 1.0

IETF RFC 2543 SIP: Session Initiation Protocol 1.0

IETF RFC 3261 SIP: Session Initiation Protocol 2.0

IETF RFC 3262 Reliability of Provisional Responses in SIP. (PRACK Support)

IETF RFC 3263 Locating SIP Servers

IETF RFC 3265 SIP Specific Event Notification

IETF RFC 3326 The Reason Header Field for SIP

IETF RFC 3515 SIP REFER Method.

IETF RFC 3824 Using E.164 numbers with SIP

IETF RFC 3903 SIP extension for Event State Publication


23

Specifications – Applications on WAS.

Many SIP related RFCs can be supported by the applications written on WAS SIP.

2848, 2976, 3050, 3087, 3264, 3266, 3312, 3313, 3319, 3327, 3372, 3398, 3428, 3455, 3578, 3603, 3608, 3665, 3666, 3680, 3725, 3840, 3842, 3856, 3857, 3959, 3960, 3976, 4032, 4092, 4117, 4235, 4240, 4353, 4354, 4411, 4457, 4458, 4483, 4497, 4508


24

Performance Monitoring Available in WAS 6.1

# of active SIP application sessions for the whole container

# of active SIP sessions for the whole container

# of active SIP sessions / application

# of active SIP Application Sessions per application

# of SIP transactions / sec

Average number of messages per second handled by the container and calculated over a configurable period.

# of new SIP Application sessions / sec

Call arrival rate - Average number of new application sessions, per second, calculated over a configurable period.

Number of messages, of each type, coming in and out of each application

Some others

® ibm software group © 2007 ibm corporation introduction to sip in websphere erik burckart...

Documents

ack sip

sip url

sip work

sarah dials todd sip2

user agents sip nodes

email address sip

hello sarah

user agent b2bua