Overview of VOIP (Voice Over Internet Protocol)/ Internet Telephony

The Internet is a worldwide network of computer networks. Computers can send messages to each other via the Internet (Email is the most familiar example). However, audio can also be digitized and passed between computers just like any other data type. This is possible using VOIP (Voice over Internet Protocol). That is, VOIP (Voice over Internet Protocol) is the ability to transfer voice over the Internet Protocol (IP) of TCP/IP protocol suite.
"VOIP", "IP Telephony", "Internet Telephony" are used interchangeably. It is also defined as the ability to transfer voice, fax and video over IP.
History:
1995 - VocalTec has first introduced IP Telephony software product "Internet Phone" in 1995. This year is called the year of the Hobbyist.
1996 The year of Gateway.
1998 The year of Gatekeeper
1999 The year of the application
System Needs:
Gateways: These are used to adapt traditional telephony to the Intenet.
Gatekeepers: Responsible for address resolution and call routing.
Codec's: Coders are used for efficient bandwidth utilization. The coder-decoder compression schemes (CODEC's) are enabled for both ends of connection and the conservations proceeds using Real-time Transport Protocol (RTP)/ User Datagram Protocol (UDP)/Internet Protocol (IP) as the protocol stack.
VOIP Explained:
In VOIP systems, analog voice signals are digitized and transmitted as a stream of data packets over a digital data network (called packet switched networks).
In public switched telephone networks or PSTN (called Circuit-switched networks), a telephone call is reserved an end-to-end physical circuit between the origin and the destination for the duration of the call. Hence, for this duration of the call, the circuit is fully available to that call and is not available to any other network users. Whereas in packet switched networks, instead of reserving a circuit between endpoints, messages or files are broken up into many small packets and each packet might be taking different route from origin to destination. Thus circuit switched networks have poor utilization of network resources whereas this is eliminated in packet switched networks.
Key Advantages:
Low cost
Add-on services and unified messaging
Merging of Voice and data
Challenges:
Quality of Service (QoS)
Quality of Voice (QoV)
Standards and Interoperability

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Software Reviews: Review of MSP

Microsoft Project popularly called as MSP is the most useful and handy software for managing a project. It is the most popular Project Management Software that helps to monitor the health of the project. In this article, I want to share my experience with this software from a new user perspective. This software is very user friendly, but one needs practice or a good training is needed to understand the all the features and how to use them and when to use these.

Features that I am very impressed with:
First it's user friendliness. And I am really impressed with the features that support the Project Management Life Cycle :
a) Ability to define tasks, sub-tasks, project phases, create dependencies between tasks, define holidays
b) Earned Value generations, (basically the cost management and health of the project),
c)Resource management,
d)Generate various reports,
Ability to
e) merge projects into a final project,
f) interface with other Time management systems like WMS.
g) to export to different formats like Excel sheet, HTML.
h) work load balancing of resources
Creating the project:
Once you decide on the tasks, sub-tasks, resources start and finish dates etc., creating a project is next the step and using MSP comes in handy with feature of defining tasks and sub-tasks, ability to assign tasks to the resources, ability to define milestones and ability to put constraints on the tasks, etc.,.
Monitoring the Health of the Project:
As the project is on going, the health of the project can be monitored using the MSP ability to generate EV, SV, CV, SPI and CPI and helps to take appropriate actions.
Reports:
This is one of the excellent features. A number of different reports can be generated and even custom (meaning you can only those fields that you want) reports can be generated.
Training: I recommend this software for anyone who is interested in Project Management. And recommend a training of at least 4 days and rest can be learned practically.
Upgrading: Definitely, we upgrade to the latest version always.
Difficulties:
1. Could not find a way to generate resources work load per month when the work is spread is few days in a month.
2. There is no way to mail the reports or status.

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Overview of SQL

SQL (Structured Query Language), pronounced as SEQUEL' is the language used by most relational database management systems to query or access data. The language was developed by IBM in the 1979. Oracle corporation introduced the first commercially available implementation. SQL has become the de-facto industry standard language for relational databases. The American National Standards Institute (ANSI) adopted SQL as the standard language for RDBMSs in 1986.
The International Standards Organisation (ISO) has also adopted SQL as the standard language for the RDBMSs.
All major RDBMSs support some form of SQL and most RDBMS vendors intend to comply with the ANSI standard.
Features of SQL:
SQL is a non-procedural language, in other words you specify what information you require, not how to get it.
It allows you to specify the types of things you want to see in terms of results you want.
It processes sets of records rather than a single record at a time.
It provides automatic navigation to data.
It provides variety of commands for carrying out different tasks. Using these SQL statements can be formed to access the data.
Allows access to the database, execute queries against database, retrieve data, delete records, update records etc.,
Works with different databases like MS Access, DB2, Informix, MS SQL Server, Oracle, Sybase etc.,
Types of SQL statements:

SQL provides different statements for carrying out different queries/activities against the database and these can categorized as follows:
DDL (Data Definition Language): Used to create, modify & delete database structures but not data.

Example commands: Create, Drop, Truncate, Alter
NOTE: Every DDL command implicitly issues a COMMIT command to the database. (If you are a new user, you need to refer oracle documentation for details on COMMIT)
DML (Data Manipulation Language): Allows changing of data within the database.
Example commands: Insert, Delete, Update
TCL (Transaction Control Language): Controls activities inside user's session, saving changes discarding changes, making logical breakpoints within transactions.

Example commands: Commit, Rollback, Savepoint
DCL (Data Control Language): Controls access to the data.
Example commands: Grant, Revoke.
DQL (Data Query Language): Allows getting data & impose ordering upon it.
Example command: Select
Embedded SQL: It allows to embed languages like C, C++ etc.,. SQL is a powerful language but there are queries that cannot be expressed in SQL, for example displaying data in the User Interface, printing a report etc., and hence embedded SQL was needed.

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Overview of Distance Learning

Distance learning: An overview

Why people choose Distance Learning:
In this fast paced world, Earn while Learning has become the de-facto for most of the people. And this is possible with the Distance learning education mode and this has become the most preferred way of education worldwide as it enables one to earn while learning. Specifically after completing the minimum education level like Bachelors Degree, many people prefer to join job and to pursue higher studies like Distance learning M.Sc, Distance learning M.B.A etc., And the advantage of this mode of education is that by the time the candidate completes these courses, he / she might have gained 2 / 3 years of work experience which increases the scope of getting better job or promotion in the current job, good pay package and hence better quality of living, job satisfaction etc.,

Basically, people choose Distance Learning to support their family economically and also to have financial independence and support to pursue their education.
Many people go for either full-time or part-time jobs so that they have the time to pursue the Distance learning courses. Generally, for these Distance Learning courses, classes called contact classes (in India) would be conducted for 1 or 2 month(s) before the exams and at least 75% of the attendance is compulsory. Hence, the candidates plan to attend these classes and prepare for the exams. However, depending on the experience level or as per the guidelines specified by the Distance Learning Institute or Organization, attending Contact classes can be exempted.

Various levels of Distance learning programs:
- Bachelors Degree
- 2 or 3 years Masters Degree
- 1 year P.G.Diploma courses

Few of the most popular programs available in India:
- Distance Learning M.Sc in Mathematics, Literature
- Distance Learning M.B.A -
- Distance Learning M.Tech in IT
- Distance Learning PGDCS
- Distance Learning PGDBAM
- Distance Learning PGDLAN
- Distance Learning PGDPM

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Selenium Core Installation

Selenium core Installation Instructions for deploying on the weblogic server 9.1:
1. Extract the selenium-core-0.8.3.zip into a custom folder say selenium-core any where outside the server. This will be the source of the deployable unit on the Administration Server
2. In this custom folder add WEB-INF folder structure:
· WEB-INF
· Under this WEB-INF directory, create the following:
Ø src (empty folder)
Ø classes (empty folder)
Ø lib (empty folder)
Ø web.xml
In this file add the content <web-app></web-app>.

3. Start the weblogic from the domain where your application is deployed.
4. Create domain say selenium NOTE: This is outside selenium-core directory and also the server.
For this
Ø cd $BEA_HOME
Ø Create the domain using config.sh which is under $BEA_HOME/ weblogic91/common/bin (which is same as WL_HOME/common/bin).



NOTE: Default values can be replaced
5. Start the weblogic server from <domain>/bin. In this case, selenium/bin
6. open console and goto deployments and deploy the total selenium core folder (open deployment)
i. Opening console: In the web browser type the url with appropriate values for host and port:

http://<host>:<port>/console

ii. Go to deployments and deploy the total selenium core folder by clicking on Install



7. Start the deployment by clicking start button.
8. To verify the installation: In the web browser type the following with appropriate values for host and port:
http://<host> :<port>/selenium_core/core/TestRunner.html

The expected Result:

9. Now, Selenium is installed successfully and ready to work on.

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Selenium Test Automation Tool

Selenium is an open source Test automation tool for web applications. Selenium Core tests run directly in a browsers viz., Internet Explorer, Mozilla and Firefox on Windows, Linux, and Macintosh.

To start with Selenium core Tool, it is a good idea to start with Selenium IDE which is a Firefox addon. Selenium IDE is a record and play tool which generates code as the user travels the web pages.

I have found that there is not much documentation available on installing Selenium core and hence I have written a 9-step installation instructions Selenium Core Installation

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