Skype

Skype is a software program created by the Swedish and Danish entrepreneurs Niklas Zennstrom and Janus Friis. Skype lets users make phone calls over the Internet to other Skype users for free, or cell phones in exchange for a fixed price. Additional features include instant messaging, file transfer, short message service, video conferencing and its ability to circumvent firewalls.

The Skype Group, acquired by eBay in September 2005, is headquartered in Luxembourg with offices in London, Tallinn, Tartu, Prague and San Jose, California. Skype experienced rapid growth in both popular usage and software development since the release of both their freedom and their payment services.

Skype Features

Skype Features

SkypeOut

SkypeOut allows Skype users to call traditional telephone numbers, including mobile phones, in exchange for a fee. This rate is as low as U.S. $ 0.021 per minute for most developed countries, and as high as U.S. $ 2.142 per minute for calls to the dependence of the island of Diego Garcia. From January 2007, Skype also charges an equivalent of 0.039 € for each SkypeOut call, in addition to the ordinary rate. After 180 days of not making a SkypeOut call Skype balance expires. As of January 30, 2007, SkypeOut calls to Canada and the United States are no longer free.

SkypeOut calls to most toll free numbers in France (+33800, +33805, 33809), Poland (48,800), United Kingdom: (+44500, +44800, 44808) and the United States and Canada: (+1800, +1866, 1888) are free to all users of Skype, even if they have the SkypeOut service. However, for many other countries SkypeOut does not support calling toll-free number and the rate of premiums, and no SkypeOut call emergency numbers (such as 112 the universal emergency number for GSM mobile phones, 911 in Canada and the U.S. . UU. 000 in Australia and 999 in the United Kingdom).

Skype In

Skype In allows Skype users to receive calls on their computers marked by regular phone subscribers to a local phone number for Skype. Allows users to subscribe to the numbers in Australia, Brazil, Chile, Denmark, Slovenia, Spain, Estonia, Finland, France, Germany, Hong Kong, Ireland, Japan, Mexico, New Zealand, Poland, Romania, Sweden, Switzerland, United Kingdom, and United States.

For example, a user in San Francisco could create a local phone number in Helsinki. Calls Helsinki would pay only local rates to call that number. Some jurisdictions such as France and Norway, however, prohibit the registration of their local phone numbers to anyone without a physical presence or citizenship in the country.

Videoconferencing

First introduced in January 2006, Skype offers video conferencing for Windows, Mac OS X and Linux (Skype 2.0 or higher required.)With version 3.6.0.216 for Windows, Skype now supports "High Quality Video" with the quality and characteristics (eg, full screen display on the screen) similar to those found in the middle of the range of systems video-conference.

Software and system

Software and system

Operating Systems
Now there are versions for Microsoft Windows (2000, XP, Vista and Windows Mobile), Mac OS X (Intel and PPC) and Linux (32-bit x86). For Windows, Skype can also be run from a USB memory device, without needing to be installed on the host computer. The Linux version runs on FreeBSD through its binary compatibility layer for Linux. Skype can also be run on Solaris branded zones.

The Windows user interface was developed in Pascal using Delphi, the Linux version is written in C + + with Qt, and Mac OS X version is written in Objective-C with Cocoa.

Skype on mobile devices
Skype offers its own branded mobile phone Skypephone, which runs a BREW OS. Skype is also available on mobile devices running Windows Mobile Symbian The official version is currently under development. Skype is also available on Symbian and Java as part of X-Series. And thanks to a developer, it is also possible to run Skype on a Symbian environment using Fring, which also provides other services. It has just released firmware 3.90 PSP Slim in late January 2008.

Skype protocol

Skype protocol
Skype uses a proprietary Internet telephony (VoIP) network. The protocol has not been made publicly available by Skype and official applications using the protocol is closed source. The main difference between Skype and VoIP clients is that Skype operates on a peer-to-peer model, rather than the more traditional client-server model. The Skype user directory is entirely decentralized and distributed among the nodes of the network, which means that the network can scale very easily to large sizes (currently about 240 million users) without a complex and costly centralized infrastructure .

Use of Resources
Skype accesses the hard drive several times a minute. This can be verified by looking at the HDD activity LED, or by using a file access monitor such as FileMon. As Internet bandwidth of, some are selected by the users of software to act as "supernodes."Under certain conditions, Skype is reportedly willing to accept thousands of connections, but is said to be limited to 40 kb / s upload and download.

Skype Security

Skype Security

Ensure the communication is a feature of Skype. Encryption can not be activated or deactivated. The user is not involved in the encryption process and therefore do not have to deal with issues of public key infrastructure. Skype reportedly uses non-proprietary, widely trusted encryption techniques: RSA key for the negotiation and the Advanced Encryption Standard to encrypt conversations.

Skype provides an uncontrolled registration system for users: registration requires no proof of identity. While this allows users to use the system safely without revealing identities of real life to other users of the system, the lack of authentication means that there is no guarantee that those who are in communication with those who say they are in life real. The downside of this is that it is easy to use personal names (but not identity) of a trusted person as a Skype nickname and trick a naive user into revealing information or executing a program sent to them.

¿Que es Skype?

Skype es un programa de software creado por el sueco y el danés Niklas Zennström empresarios y Janus Friis. Skype permite a los usuarios hacer llamadas telefónicas a través de Internet a otros usuarios de Skype de forma gratuita, o a los teléfonoscelulares y fijos a cambio de un precio. Las características adicionales incluyen la mensajería instantánea, transferencia de archivos, servicio de mensajes cortos, videoconferencias y su capacidad de burlar cortafuegos.

El Grupo de Skype, adquirida por eBay en septiembre de 2005, tiene su sede en Luxemburgo, con oficinas en Londres, Tallin, Tartu, Praga y San José, California. Skype experimentado un rápido crecimiento tanto en el uso popular y el desarrollo de software desde el lanzamiento, tanto de su libertad y de sus servicios de pago.

Características de Skype

SkypeOut

SkypeOut permite que los usuarios de Skype llamar a números de teléfono tradicionales, incluidos los teléfonos móviles, a cambio de un precio. Esta tasa es tan bajo como 0,021 dólares de los EE.UU. por minuto para la mayoría de los países desarrollados, y tan alto como 2,142 dólares de los EE.UU. por minuto para lasllamadas a la dependencia de la isla de Diego García. A partir de enero de 2007, los cargos de Skype también un equivalente de 0.039 € para cada llamada de SkypeOut, además de la tasa ordinaria. Después de 180 días de no hacer una llamada de SkypeOut Skype equilibrio expira. A partir del 30 de enero de 2007, SkypeOutllamadas a Canadá y los Estados Unidos ya no son libres.

SkypeIn

SkypeIn permite a los usuarios de Skype de recibir las llamadas en sus ordenadores marcados por los abonados de teléfonos regulares a un número de teléfono local de Skype. Permite a los usuarios suscribirse a los números en Australia, Brasil, Chile, Dinamarca, Eslovenia, España, Estonia, Finlandia, Francia, Alemania, Hong Kong, Irlanda, Japón, México, Nueva Zelanda, Polonia, Rumania, Suecia, Suiza, Reino Unido, Y los Estados Unidos.

Videoconferencia

Presentado por primera vez en enero de 2006, Skype ofrece videoconferencia para Windows, Mac OS X y Linux (Skype 2.0 o superior requerido). Con la versión 3.6.0.216 para Windows, Skype es ahora compatible con “ Vídeo de alta calidad” con la calidad y características (por ejemplo, a pantalla completa y pantalla en pantalla) similares a las que se encuentran en medio de gama de sistemas de video-conferencia.