Skype
This article is about the VoIP software. For the company, see Skype Technologies.
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Skype
Screenshot [show]
Developer(s)
Microsoft Skype Division
Initial release
August 2003
Stable release
Android
3.0.0.6181 [edit] (20 November 2012; 50 days ago)[1][2]
iOS
4.1.2 [edit] (13 November 2012; 57 days ago)[3][4]
Linux
4.1.0.20 [edit] (15 November 2012; 55 days ago)[5]
Microsoft Windows
6.0.0.126 (Desktop app)[edit] (15 November 2012; 55 days ago)[6]
1.2 (Windows Store app)[edit] (22 November 2012; 48 days ago)[7]
OS X
6.0.60.2968 [edit] (15 November 2012; 55 days ago)[8]
Symbian
2.1 [edit] (2 February 2012; 11 months ago)[9]
Windows Phone
2.0 [edit] (12 November 2012; 58 days ago)[10]
[±]
Preview release
[±]
Written in
Embarcadero Delphi,Objective-C (iOS, Mac OS X), C++ with Qt4 (Linux)
Operating system
iOS, Windows XP,Windows Vista, Windows 7, Windows 8, Mac OS X,Windows Phone,Blackberry OS, HP WebOS, Symbian, Androidand Linux
Available in
Multilingual
Type
Voice over IP, instant messaging,videoconferencing
License
Proprietary, some paid features
Website
www.skype.com
Part of a series on
Skype
Skype Technologies
Features of Skype
Skype protocol
Skype security
v t e
Skype (pron.: /ˈskaɪp/) is a proprietary Voice over IP service and software application.
Skype was first released in 2003 written by Estonian developers Ahti Heinla, Priit Kasesalu, and Jaan Tallinn, who had also originally developed Kazaa.[11] It developed into a platform with over 600 million users and was bought by Microsoft in 2011 for $8.5 billion.[12]
The service allows users to communicate with peers by voice using a microphone, video by using a webcam, and instant messaging over the Internet. Phone calls may be placed to recipients on the traditional telephone networks. Calls to other users within the Skype service are free of charge, while calls to landline telephones and mobile phones are charged via a debit-based user account system. Skype has also become popular for its additional features, including file transfer, and videoconferencing. Competitors include SIPand H.323-based services, such as Linphone[13] and Google Voice.
Skype has 663 million registered users as of EOY 2010.[14] The network is operated byMicrosoft, which has its Skype division headquarters in Luxembourg. Most of the development team and 44% of the overall employees of the division are situated in Tallinnand Tartu, Estonia.[15][16]
Unlike most other VoIP services, Skype is a hybrid peer-to-peer and client–server system. It makes use of background processing on computers running Skype software. Skype's original proposed name (Sky Peer-to-Peer) reflects this fact.
Some network administrators have banned Skype on corporate, government, home, and education networks,[17] citing reasons such as inappropriate usage of resources, excessive bandwidth usage, and security concerns.[18]
Contents
[hide]
1 History
1.1 eBay acquisition
1.2 Silver Lake, Andreessen Horowitz and the Canada Pension Plan Investment Board acquisition
1.3 Microsoft acquisition
2 Features
3 Usage and traffic
4 System and Software
4.1 Client applications and devices
4.2 Protocol
4.3 Protocol detection and control
4.4 Audio codecs
4.5 Video codecs
5 Release history
5.1 Windows
5.2 Mac OS X
5.3 Linux
6 Security and privacy
6.1 Service in the People's Republic of China
7 Customer service
8 Educational use
9 Outages and downtime
10 See also
11 References
12 External links
[edit]History
Main article: Skype Technologies#History
Skype was founded in 2003 by Mr Dhamija, Janus Friis from Denmark and Niklas Zennström from Sweden.[19] The Skype software was developed by Estonians Ahti Heinla, Priit Kasesalu, and Jaan Tallinn, who together with Friis and Zennström were also behind the peer-to-peer file sharing software Kazaa.[20] In August 2003, the first public beta version was released.
[edit]eBay acquisition
On 12 September 2005, eBay Inc. agreed to acquire Luxembourg-based Skype Technologies SA for approximately US$2.6 billion in up-front cash and eBay stock, plus potential performance-based consideration.
[edit]Silver Lake, Andreessen Horowitz and the Canada Pension Plan Investment Board acquisition
On 1 September 2009, it was announced that eBay was selling 65% of Skype for US$1.9 billion, valuing Skype at US$2.75 billion.
[edit]Microsoft acquisition
On 10 May 2011, Microsoft Corporation acquired Skype Communications, S.à r.l for US$8.5 billion.[21] The company was incorporated as a division of Microsoft, and Microsoft acquired all of the company's technologies with the purchase. This was completed on 13 October 2011.[21][22]
[edit]Features
Main article: Features of Skype
Registered users of Skype are identified by a unique Skype Name, and may be listed in the Skype directory.[23] Skype allows these registered users to communicate through both instant messaging and voice chat. Voice chat allows telephone calls between pairs of users and conference calling, and uses a proprietary audio codec. Skype's text chat client allows group chats, emoticons, storing chat history and editing of previous messages. Offline messages were implemented in a beta of version 5, but removed after a few weeks without notification. The usual features familiar to instant messaging users — user profiles, online status indicators, and so on — are also included.
The Online Number, a.k.a. SkypeIn, service allows Skype users to receive calls on their computers dialed by conventional phone subscribers to a local Skype phone number; local numbers are available for Australia, Belgium, Brazil, Chile, Colombia, Denmark, theDominican Republic, Estonia, Finland, France, Germany, Hong Kong, Hungary, Ireland, Japan, Mexico, New Zealand, Poland,Romania, South Africa, South Korea, Sweden, Switzerland, Turkey, the Netherlands, the United Kingdom, and the United States.[24][25]A Skype user can have local numbers in any of these countries, with calls to the number charged at the same rate as calls to fixed lines in the country.
Skype supports conference calls up to 25 people at a time. Skype also supports video chat, including screen sharing, between two people for free. Group video calling is available for Premium subscribers between a maximum of 10 people.[26]
Skype does not provide the ability to call emergency numbers such as 112 in Europe and 911 in North America.[27] The U.S. Federal Communications Commission (FCC) has ruled that, for the purposes of section 255 of the Telecommunications Act, Skype is not an "interconnected VoIP provider".[28] As a result, the U.S. National Emergency Number Association recommends that all VoIP users have an analog line available as a backup.[29]
In 2011 Skype partnered with Comcast to bring its video chat service to Comcast subscribers via their HDTV sets.[30]
[edit]Usage and traffic
This section may need to be updated. Please update this section to reflect recent events or newly available information. Please see the talk page for more information. (February 2012)
[show]Usage and traffic
Year
International call market share
2005
2.9%[43]
2006
4.4%[43]
2008
8%[41]
2010
13%[44]
In January 2011, after the release of video calling on the Skype client for iPhone, Skype reached a record 27 million simultaneous online users.[45] This record was broken with 29 million simultaneous online users on 21 February 2011,[46] and again on 28 March 2011 with 30 million online users.[47] On 25 February 2012, Skype announced that it has over 32 million users for the first time ever.[48] As of 5 March 2012, it has broken to 36 million simultaneous online users.[49] In June 2012, Skype had surpassed 70 million downloads on an Android Device.[50]
On 19 July 2012, Microsoft has announced that Skype users have logged 115 billion minutes of calls over the quarter, up 50% since the last quarter.[51]
[edit]System and Software
[edit]Client applications and devices
Skype runs on a number of platforms including Microsoft Windows (XP, Vista, 7, 8), OS X (10.5.8 or newer), Linux (Ubuntu and others),Windows Phone, iOS and Android.
On 29 October 2007, Skype launched its own mobile phone under the brand name 3 Skypephone, which runs a BREW OS.[52]
Skype also offers a Skype Wi-Fi Phone which is a wireless mobile phone that allows users to make Skype calls, using a wireless Internet connection. The Skype Wi-Fi Phone has an on-screen menu that lets Skype users see who is online and available to talk, similar to what is seen on a PC. It can also be used to talk with non-Skype users. SkypeOut minutes can be used to call any phone for a low price and no monthly fee. The Skype Wi-Fi phone does not contain a web browser and so can not access hotspots that require web-based login or authentication.[53]
Skype 6.0 running on Windows 7
Skype 4.0.0.7 running on Ubuntu Precise Pangolin
Skype 1.2.0.0 running onWindows Phone
Skype 4.2.2 running on iOS
Skype 3.0 running on Android
Other platforms officially supported include:
The Nokia N800, N810 and N900 Internet Tablets, which use the Maemo environment
The Nokia N9 comes with Skype voice calling and text messaging integrated however lacks video-calling.
Both the Sony mylo COM-1 and COM-2 models
The PlayStation Portable Slim and Lite series, though the user needs to purchase a specially designed microphone peripheral. ThePSP-3000 has a built in microphone which allows communication without the Skype peripheral.[54] PSP Go has the ability to useBluetooth connections with the Skype application, in addition to its built-in microphone.[55] Skype for PlayStation Vita may be downloaded via the PlayStation Network in the U.S. It includes the capability to receive incoming calls with the application running in the background.
The X-Series together with mobile operator 3. However this uses a regular mobile phone call and iSkoot[56] to a Skype gateway, rather than mobile Internet. Other companies produce dedicated Skype phones which connect via WiFi
Some devices are made to work with Skype by talking to a desktop Skype client or by embedding Skype software into the device. These are usually either tethered to a PC, or have a built-in Wi-Fi client to allow calling from Wi-Fi hotspots like the Netgear SPH101 Skype Wi-Fi Phone, the SMC WSKP100 Skype Wi-Fi Phone, the Belkin F1PP000GN-SK Wi-Fi Skype Phone, the Panasonic KX-WP1050 Wi-Fi Phone for Skype Executive Travel Set, the IPEVO So-20 Wi-Fi Phone for Skype and the Linksys CIT200 Wi-Fi Phone. There are also embedded cordless Skype phones based on DECT, which do not need a PC either, like the DUALphone 3088 from RTX. Netgear and SMC's Wi-Fi phones are considered the two major competitors in the market, with reviews of the Wi-Fi phones giving them equal coverage.[citation needed]
Third-party developers, such as Truphone, Nimbuzz IM and Fring, have allowed Skype to run in parallel with several other competing VoIP/IM networks (Truphone and Nimbuzz provide truphoneOut and NimbuzzOut as a competing paid service) in any Symbian or Java environment. Nimbuzz has made Skype available to BlackBerry users. In July 2010, however, Fring disabled users from accessing Skype despite claiming that Skype themselves disabled the access;[57] Fring had provided mobile video calling over Skype as well as support for the Android platform. Nimbuzz discontinued support on request of Skype in October 2010.[58]
Before and during the Microsoft acquisition, Skype withdrew licensing from several third parties producing software and hardware compatible with Skype. The Skype for Asterisk product from Digium was withdrawn as "no longer available for sale".[59] The SenaoSN358+ long-range (10–15 km) cordless phone were discontinued due to loss of licenses to participate in the Skype network as peers. In combination these two products made it possible to create roaming cordless mesh networks with robust handoff.
[edit]Protocol
Main article: Skype protocol
Skype uses a proprietary Internet telephony (VoIP) network called the Skype protocol. The protocol has not been made publicly available by Skype and official applications using the protocol are closed-source. Part of the Skype technology relies on the Global Index P2P protocol belonging to the Joltid Ltd. corporation. The main difference between Skype and standard VoIP clients is that Skype operates on a peer-to-peer model (originally based on the Kazaa software[60]), rather than the more usual client–server model (note that the very popular SIP model of VoIP is also peer-to-peer, but implementation generally requires registration with a server, as does Skype).
As far as networking stack support, Skype currently only supports the IPv4 protocol. It lacks support for the next generation Internet protocol, IPv6.[61]
[edit]Protocol detection and control
Many networking and security companies claim to detect and control Skype's protocol for enterprise and carrier applications. While the specific detection methods used by these companies are often private, Pearson's chi-squared test and Naive Bayes classification are two approaches that were published in 2007.[62] Combining statistical measurements of payload properties (such as byte frequencies and initial byte sequences) as well as flow properties (like packet sizes and packet directions) has also shown to be an effective method for identifying Skype's TCP- and UDP-based protocols.[63]
[edit]Audio codecs
G.729 and SVOPC. Skype added a Skype-created codec called SILK to Skype 4.0 for Windows and other Skype clients. SILK is intended to be "lightweight and embeddable".[64]
[edit]Video codecs
VP7 is used for versions prior to Skype 5.5[65][66][67][68][69]
As of version 5.7 VP8 is used for both group and one on one standard definition video chat and H264 is used for 720p and 1080p high definition group and one on one video chat.[70][71] skype messenger ki madad se aap chat aur live baat kar sakte hien.es ke elawa aap es ki madad se video call kar sakte hein.es software ko download karne ke liye
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