tutoring.net - a communication portal for e-learning

Tutoring the 21st Century

Tutoring.NET - A communication portal for e-learning

brought to you by: Markus Beier, Caroline Daniel, Daniel Dudaszek, Marc Hermann, Stéphanie Lecat, Daniel Toeller


• Contact point for students and tutors

• Give students the opportunity to contact their tutors independent of location and time.

• Tutors shall be able to decide when, where and how they can be reached.

Goals :


• Web portal as a meeting point

• SIP enables the new ways of communication

How we achieved this :


Functionality of the web site

4. Admin

1.General Features

2.Student

3.Teacher


Functionality of the web site – Generality

• Register (see student and teacher part)• Log-in• Send an email• Make a call (SIP or Netmeeting) • Log-out


Functionality of the web site - Student • Register yourself• Messages from the teachers• Courses you can join or quit, courses you are already in• Students work group• Students in your courses• Teachers of your courses• Edit your profile


Functionality of the web site - Teacher • Ask the administrator to register• Manage your messages• Courses you are in charge of, deletion, addition• Teacher work group• Students in your courses• Edit your profile


Functionality of the web site - Admin

• Create a teacher account• See the list of all the work group (student and

teacher)• See the list of all the students• See the list of all the teachers• See the list of all the courses


Database

1. MySQL

2. Our database


Database – Advantage of MySQL

• MySQL is a robust and performing SQL server• MySQL easily work with scripts language as PHP• PhpMyAdmin is an easy to learn interface to

manage MySQL database • Not perfect but...


Our Database – schema


Dynamic Web Pages Web page created in response to the request of a user, whose

contents is variable Collecting and sending to the Web server the information entered by

the user in a form Transmission of this data to a script or an application for their

processing Querying of a Database

Returning the result to the user in a HTML page


Use of PHPWhat is php

It is a script language

Embedded in a normal HTML page

Executed by the Web server

It will enable us to manage and use our MySQL database

And using data entered by the visitors


How a PHP program looks likethe tags <?php and ?> represent the beginning andthe end of a PHP program .

Example : <html><head><title>Example</title></head> <body> <H1><?php printf(“ the sum equals : $a + $b “,2,3);

?> </H1> </body></html>


ResultAt the end of its execution the part which goes from

<?php to ?> is removed or replaced by the result of the program. For this example the result we have is :


The advantage of the use of PHP The PHP Code is executed only by the server

Compatible with all kind of browsers

Free software and availability of the source code

Simplicity of writing of scripts

Simplicity of interaction with databases

Integration within many Web servers (Apache, Microsoft IIS, ...)


Personalised webpages


– Functionalities of Tutoring.net site require personalised webpages

– Example: two students which connect to the same page


– main problem: stateless HTTP protocolrequest response principle


• Solution – Session:

• defines an state between server and client• problem here: how to identify a unique user• generate Session ID

– possibilities to pass the Session ID:• use the GET Parameter• store it in a cookie


• Session Management:– At the server side:

• Store Informations about each active Session • Database, shared memory,filesystem

– Sessions properties:• store variables• have a lifetime


• Authentication:– allow webserver to identify client

• Methods to implement Authentication– Basic Authentication – Session Based Authentication


Basic Authentication Session Based Authentication

Basic Authentication vs. Session Based Authentication


+ - Basic - Authentication

easy implementation

no automatically logout possible

no web design possible

the user might be lead to uncertainty

Session Based Authentication

automatic logout possible

web design possible

necessity to implementate all Session functionalities

Basic Authentication vs. Session Based Authentication


• PHPLIB

• overview of selective Features:Session ManagementUser ManagementAuthenticationDatabase Access


• Example Authentication:


Access to page which requires authentication


Login form is shown first which is totally independent from the protected site


If login is valid the requested site is shown


SIPSession Initiation Protocol

-How to initiate a session with SIP


1. Purpose of the protocol2. Basics3. Example

SIP – Session Initiation Protocol


• Mr. Blue wants to call Mr. White via VoIPQuestions:

– Which IP has Mr. White– which type of session shall be initiated– which parameters has the session

Solution: SIP



• textbased protocol, uses UDP (TCP)• closely related to HTTP (same response

codes, authentication schemes)• clear separation: signalling of the session –

type of session (e.g. telephone call, game)• uses the proxy principle• control via 6 methods: REGISTER, INVITE,

ACK, BYE, OPTIONS, CANCEL




Sample SIP MessageINVITE sip:[email protected] SIP/2.0Via: SIP/2.0/UDP 134.155.12.22:5060From: sip:[email protected]: sip:[email protected]: sip:[email protected]: [email protected]: 27246067 INVITEContent-Length: 175Content-Type: application/sdpUser-Agent: eStara SoftPHONE

v=0o=eStara 27246067 27246067 IN IP4 134.155.12.22s=eStarac=IN IP4 134.155.12.22t=0 0m=audio 8000 RTP/AVP 0 101a=rtpmap:101 telephone-event/8000a=fmtp:101 0-15

HeaderContains the signalling information

BodyContains the description of the session


Mr. White turns on the phone

SIP Proxy

[email protected]=

12.12.12.12

REGISTER

FROM: [email protected]:12.12.12.12

Example call



SIP Proxy

[email protected]=

12.12.12.12

200 OK

Mr. White turns on the phone

Example call



SIP Proxy

[email protected]=

12.12.12.12Mr. White

waits for callsMr. Blue

places a call

INVITE

FROM: [email protected]: [email protected]

<Session Data>

Example call



SIP Proxy

[email protected]=

12.12.12.12

INVITE

FROM: [email protected]: [email protected]

<Session Data>

100 Trying

Mr. Blue places a call

Mr. White waits for calls

Example call



[email protected]=

12.12.12.12

180 Ringing180 Ringing

SIP Proxy

Mr. Blue‘s phone rings

Mr. White‘s phone rings

Example call



[email protected]=

12.12.12.12

200 OK200 OK

SIP Proxy

Mr. Blue‘s phone rings

Mr. White accepts

Example call



[email protected]=

12.12.12.12

ACK ACK

RTP audio streams

SIP Proxy

Example call

Mr. Blue ison line

Mr. White is on line



[email protected]=

12.12.12.12

SIP Proxy

Example call

Mr. Blue isoff line

Mr. White ends the call


BYEBYE


[email protected]=

12.12.12.12

ACK ACK

SIP Proxy

Example call

Mr. Blue isoff line

Mr. White is off line


Call Duration 6 minutes: Fee 6€


Call LogicProgramming Sip:• CPL(Call Processing Language)• SIP CGI (Common Gateway Interface) • SIP Servlets


What is CPL?• an XML-based scripting language for describing and controlling call services• a list of condition/action pairs

– Example:„If someone is calling during the presentation, redirect the call to the voicemail server.“

„Redirect my friends to my cell phone, anyone else to my office.“


CPL Scripts can be based on:• Caller/Callee

– Address – Name

• Call subject • Caller's organization • Call Priority • Time periods


Where does CPL run?A CPL script runs in a signallingserver, and controls actions for the set upof a particular call


CPL Script example<?xml version="1.0" ?><!DOCTYPE cpl PUBLIC "-//IETF//DTD RFCxxxx CPL 1.0//EN" "cpl.dtd">

<cpl> <incoming> <location url="sip:[email protected]

mannheim.de"> <redirect /> </location> </incoming></cpl>


CPL scripts can be createdin 2 ways

1.Advanced users can do it by hand2.With GUI based tools (Indigo CPL Editor)


Sip CGI• Similar to Web-CGI• Language-independent (Perl,C,...)• Security problem:

– CGI programs are unlimited in their power

buggy scripts may affect server only for admin


Sip Servlets• Compromise between security and

power Security provided by Java Sandbox Still powerful


Call processing overviewGenerality Security

CGI highest lowest

Servlets medium medium

CPL lowest highest

Tutoring the 21st CenturyTutoring the 21st Century

SIP User Agents

Functionality and Restrictions


• What is a User Agent ?• How does a User Agent work ?• Several used and tested UAs

• eStara Softphone• Microsoft Netmeeting• Pingtel XPressa• History Client

Overview


• A „real“ Telephone (Hardphone) with internet-software running

• A so called „Softphone“, a special software that uses Internet communication protocols to run

What is a User Agent ?

•Two „implementations“ :

•A Hard – or Software based Phone to call someone over the Internet




Overview


RTP

SIPSIP




Overview


eStara Softphone

•Also possible to run as an applet for customer services

•SIP enabled

•Three different Lines for different simultaneous calls

•Forwarding calls possible


•The only UA, which is launchable directly from the webpage

eStara Softphone


eStara Softphone

•SIP Message Log for detailed look at the SIP Messages

•The only UA, which is launchable directly from the webpage




Overview


Microsoft Netmeeting - Features

•Supports :WhiteboardsChatVideocallSharing Programs / DesktopFile Transfer

•H.323 Phone


Microsoft Netmeeting - Features

•The only UA which is integrated directly into the webpage via an Active-X-Control

•Embedded into the HTML by the <object> tag

•Buttons to control the call

•Many possibilities :

•Full UI•Only Parts of the UI


Microsoft Netmeeting - Calling

Hard-coded IP-Adress to reacha specified computer

If Netmeeting is integrated via Active-X into the webpage, the call is directly made




Overview


The Hardphone

Pingtel XPressa

•Multiple simultaneous calls

•Runs Java and SIP

•World´s first Java VoIP-Phone


The Softphone

Instant Xpressa

•Emulation of the Pingtel XPressa•Xdk to develop Java Apps




Overview


• HistoryClient•Prototype - Software for the tutor

•Shows Notes that were made during earlier sessions with the caller to make it easier to keep track of the problems.


DEMONSTRATION


• On a technical level– SIP, protocols for videoconferences, PHP

• On a personal level– Intercultural work, dealing with misunderstandings

Assessment


Ideas for the future

• Improve billing function

• Make a SIP call to a telephone network

• Getting CPL scripts to work


Thank you for your attention


?

tutoring.net - a communication portal for e-learning

Documents