apis for next-generation service creation jonathan rosenberg chief scientist

APIs for Next-Generation Service Creation

Jonathan RosenbergChief Scientist

www.dynamicsoft.comSIP 2001 2.23.01APIs for Next-Generation Service Creation

Voice Over IP Today

Toll-bypass has Been the Primary Motivation Cheap long distance Service transparency

Cost Differentials are Rapidly Disappearing Retail long distance is now at 4 cents a minute Carriers are exploring flat rate plans

Service Transparency is Far Away QoS issues 911, 1000 features in the 5ESS Huge existing penetration of the phone in the US and worldwide


The Question of Customer Value

If IP Telephony Service is Not Cheaper, Better or Different,

Why Purchase It?


The Answer

IP Telephony Enables Innovative New Services Created by Combining Applications Web Email Chat Presence

The Killer App for VoIP Lives Within

These Combined Services


Combined Services Enable Service Provider Differentiation

Integrating Applications Yields Exponential Services Growth

Service Provider Differentiation Flows Naturally from this Applications Diversity

Combined Services

VoiceVoice +Web

Voice +Web +Email

Voice +Web +Email +Presence


Web Interactive Voice Response (Web IVR)

IVR Woes Difficult to navigate Inconsistent menu operations Slow to use

Big Idea Web a natural medium!

How Does It Work If a call to some number is

from a PC, after hours, the user is returned a web page

If the call is from a phone connected to a gateway, they are connected to a normal voice system

INVITEHTTP

Web Content

Web IVR Service

INVITE

VoiceXML

Gateway

PSTN

Phone

PC Web Server

200 OK

200 OK

300 Go Web


How to Build These Services?

Need APIs That Provide Access to SIP Specific Constructs Many combined services rely on SIP support for MIME, URLs, etc.

Web IVR requires setting of the Contact header to an HTTP URL Auto Conference requires SIP IMs to contain HTTP URLs

Signaling protocol independent APIs won’t work Parlay JTAPI

“The call” is not the central feature of the application any longer State machine exists at a higher level Call machine not important



Leverage the Vast Web Developer Community Web developers to telecom developers is 100:1 Every graduate CS student has done some web programming, almost

none do telecom programming Innovation will come from two guys in a garage

How to Leverage Them? Provide APIs similar to ones they already know

Servlets, JSP, CGI, XML

APIs shouldn’t require telecom training or background Open, widely available Free servers for trial Books, magazines, developer communities

Business Models Have an Implication Too!


Changes In Web Business Models

Best-in-class companies have emerged at every layer of the business model

Applications

Transport

AOLCompuServe

Prodigy

ASPsApplications

& Hosting

Backbone ISP

Yahoo

UUNET

Hosting Companies

ASPs

Application Developers

Application PlatformsBEA WebLogic IBM WebSphere

Ecommerce.com

Accenture

Exodus

Backbone ISP

UUNET

ASPs

Amazon.com

Exodus

Hosting Companies

Backbone ISP

UUNET

VerticalMonolith

RelentlessSpecialization


Changes In Telco Business Models

Applications

Transport

AT&T

CommunicationsASPs

Applications & Hosting

ConvergedCarriers

DialpadWebley

Level (3)

Genuity

VerticalMonolith

RelentlessSpecialization

CommunicationsASPs

Hosting Companies

ConvergedCarriers

Level (3)

Genuity

Hosting Companies

CommunicationsASPs

Application Developers

Application Platforms

Converged CarriersLevel (3)

Genuity

What were once “Voice Services” are now split between converged applications and converged networks



Follow the business models as well! Relentless specialization

Benefits Rapid time-to-market Reduced costs Focus, focus, focus

API Implications APIs must support separation of developer and hoster

Servlets!


HTTP Servlets HTTP Java Servlets Widely Used in Web

Application Development

Applications Consist of Sets of HTTP Servlets, Each of Which Processes a Single Web Request in the Application

HTTP Servlets Return Web Pages to Display

HTTP Servlets Can Create “Session Data” e.g., shopping cart, that spans multiple

requests

“Container” Manages HTTP Servlet Lifecycles, Fault Tolerance, Session State

HTTP Servlets Collected into a War File – Web Archive

HTTP Servlets

Web Server

Developer

Deployer

War File


SIP Servlets Direct Application of HTTP

Servlet Model to SIP

Java-based API

Telecommunications application is a set of SIP (and HTTP!) servlets

SIP servlets process a particular SIP request or response

SIP servlets can create and access session data, call data, transaction data

SIP servlet container provides same functions as http container

CAR file equivalent of WAR file

SIP Servlets Car File

SIP Server

Developer


SIP Servlet Benefits Exposes key SIP headers,

but handles most of the SIP details for you

Supports Sending responses Proxying requests Initiating requests

Allows proxy, B2BUA applications

Calls, legs, transactions are modeled – similar in concept to HTTP Sessions

Inherits all scale and fault tolerance benefits of HTTP Servlets

public class MyServlet extends SipServlet{ public void doInvite(SipServletRequest req, SipServletResponse res) { req.getProxy(true).proxy(“sip:user@host”); }}


Call Processing Language (CPL) Output of IETF IPTEL

Group, Under IESG Review Now

A Scripting Language to Describe Call Services

Language Properties Guarantee Safety

Based on XML

Hand or Tool Authoring

Example: “Call Forward on Busy/No-answer”

Can Be Dynamically Uploaded and Instantiated by Third-parties

<?xml version="1.0" encoding="UTF-8"?><!DOCTYPE cpl SYSTEM "cpl.dtd"><cpl> <location url="sip:[email protected]"> <proxy timeout="8s"> <busy> <location url="sip:[email protected]”> <proxy /> </location> </busy> <noanswer> <location url="sip:[email protected]”> <proxy /> </noanswer> </proxy> </location></cpl>


Common Gateway Interface (CGI) HTTP CGI Widely Used in Web

Servers

Predates Servlets

Similar Model to Servlets

Primary Differences Web server spawns a separate

process to handle request Request data passed through

environment variables Web page returned by script by

writing to standard out (stdout) – i.e., printf

Script can be written in any language

Big process overhead

SIP CGI is Direct Equivalent to HTTP CGI, Just as SIP Servlets are Direct Equivalent to HTTP Servlets

SIP CGI Properties Scripts invoked on requests and

responses Scripts can output response to

send and also cause requests to be proxied

Same flexibility/overhead as HTTP CGI

Approved as Informational RFC 3050 by IETF

Information Resource Jonathan RosenbergChief Scientist+1 973.952.5000 [email protected]

apis for next-generation service creation jonathan rosenberg chief scientist

Documents

web slide

web voice

web programming

web pages

web business models

application http servlets

voice services

apis similar