Skype is a free of charge available, VoIP software, which makes free telephoning via Internet from PC to PC as well as chargeable telephoning possible in the fixed net and on mobile telephones (SkypeOut). The likewise chargeable service SkypeIn makes the accessibility possible from the conventional telephone network. Conference circuits are possible for up to five discussion participants (with certain processors the number of possible participants increases to 10, whereby only the discussion leader needs such a processor).

Characteristics

The software is characterised - contrary to many comparable programs - by the fact that it functions also behind the most Firewalls and NAT routing problem-free, since for communication among other things the TCP haven 80 is used, which normally finds for the Surfen in the World Wide Web use and is de-energised therefore in nearly all cases.

The language quality of Skype is to a large extent better due to new compression algorithms (ILBC) than with conventional telephone calls. The language quality is negatively affected however - differently than with telephones - by inferior microphones wide-spread in the PC market. Skype works at it with each standard Headset or microphone loudspeaker configuration - the equipment merged in the operating system is recognized, thus is practically each hardware supported under Microsoft Windows.

With connections from PC to PC the coding with AES-256 ensures for the the keys will with 1.024 bits RSA transfers Skype Technologies, data security FAQ, next to last question according to Skype: What for is a type of coding on skype.com, 2006. Since it concerns however a Closed SOURCE program, these data cannot be examined by everyone. They are however by one of Skype assigned "“Security evaluation"” of the renowned cryptology expert Tom Berson confirmed Tom Berson: Skype Security evaluation on skype.com with signature, 18 October 2005, English, pdf.

Since Skypes VoIP minutes is can it only with the original Skype software be used. Over the Skype API it is possible also for external programs to access functionalities of the Skype Clients and parts of the network. This is used among other things by the SAM answering set. Apart from telephoning the main employment of Skype is the Instant Messaging, whereby also Chats with several participants are possible, as well as transferring files. The moreover one a Skype PlugIn for Miranda e.g. exists IN, which makes the common use possible of Skype with other minutes in only one Instant Messenger.

The structure of Skype is in the context of a P2P-Netzes partly decentralized, for example the directory. The Authentifizierung and accounting for however are made by a central computer. Likewise connections are partly passed on from PC to PC over other Skype participants, while the discussions are completed in the fixed net over particularly for it intended computers. With telephone calls in the firm or portable radio net the possibility does not exist of using the SIP services of other Provider. This is possible only over the Skype Out function.

Version differences 

Since version 1.2 of the Windows variant Skype offers also an answering set (Voicemail) (since one knows version 1.3 as a user of the Skype answering set each user a message on the answering set left, even if this even answering set uses no Skype.) as well as the service SkypeIn liable to pay the costs on. With SkypeIn a fixed net number (so far from Germany, Estonia, Switzerland, France, Hong Kong, Great Britain, Denmark, Finland, Sweden, Norway, Poland and the USA) is assigned to the user, over which it is attainable via Skype.

Since version 1.4 is the function "„call Forwarding "“implemented, which permits it to pass via Skype which are received discussions on to other Skype Benutzerkonten or in the normal telephone network (PSTN).

With the version 2.0 the Videochat held into application introduction. The maximum dissolution amounts to pixel with 15 pictures per second.

Beta version 2,5, whose stable release for center 2006 is expected, leads among other things Skypecasts (a kind VoIP Diskussionsgruppe), SMS, an integration of the Outlook contacts and new paying possibilities (direct payment of SkypeOut from the software) einSkype Technologies: '' Praying '', 03.05.2006 Heise news: '' Beta version of the Skype software controls "“Skypecasts"” '', 03.05.2006.

Spreading

Since at the end of July 2004 is Skype as full version available and runs under Windows XP, Windows 2000 (and Windows ME as well as until further notice (version 1.4.0.84) under Windows 98 SE with the Windows version, even if this is not explicitly indicated), Linux, pocket PC and Mac OS Xth sound announcement in the Client is in the meantime more than six million user on-line (maximum daily peak value). This value became the first time to 27. March 2006 reaches. According to the official Skype Internetseite already about 26 billion minutes were obtained and over 277 million Downloads (conditions: 28. March 2006) accomplished. That means that on the average more as 20,000 discussions at the same time over Skype completed will statistics than RSS feed: Skype Statistics new feed of skype.com also, updates, English, RSS.

Skype hardware

Different manufacturers drive hardware products out, which were developed for VoIP employment with Skype. It concerns mostly cord lot telephones, whose basis station on the one hand to the similar telephone network (PSTN) are attached, on the other hand in addition, an interface (usually USB) to the connection with a PC makes itself available. From the mobile part discussions in both nets can be led. A condition alone use, which a switching of discussions in the Skype net, without an additional computer with current Skype application be attached must, is made possible however at present not yet possible.

At the 3GSM World Congress 2006 communicated the UMTS Mobilfunkunternehmen three (Hutchison 3G), whatever first video telephone IE offerer in Austria was, its plans for direct integration (so far is already e.g. possible via PDA the use) of Skype into mobile telephones, like heise mobilely to infer heise mobilely: '' 3GSM: 3 Skype brings on UMTS mobile phone '', 15.02.2006 is. In Sweden the employment with UMTS data cards is already tested, with which associated tariff an unlimited Skype use permitted. SkypeOut is likewise possible.

Criticism

At Skype the use of prop. guessing eras minutes is unfavorable. The software is not compatible with other VoIP offers, which with the open standards SIP or H.323 works. Free SIP based VoIP Clients and server are however just as in the Internet available, for example X-Lite or Jajah as Softphone and SER (SIP express rout) as SIP Proxy. Prominently within the range of the VoIP servers is at present Asterisk; on a minutes support one works.

Skype does not become certified in many enterprise networks, since the assigned Peer ton Peer technology is classified of the responsible persons as safety-relevant doubtful. The moreover one the enterprise of Skype produces for permanent data traffic, which can amount in the month to some gigabyte, without also only one telephone call to have led by its P2P-Technologie.

If the assets of the account were not used more than 6 months, the assets run off, before it is completely used up. The registered accounts remain however further active.

Trivia

Skype is nationally forbidden in the united Arab emirates probably to prevent (in order a competition to the conventional Telefonie).

See also

• Gizmo
• OpenWengo
• Ekiga

Literature

• Thor Alexander: Internettelefonie: Everything over Skype. Approximately around the world free of charge telephone. Rhombos publishing house, 2005, ISBN 3-937231-52-8
• Salman A. Baset, Henning Schulzrinne: At analysis OF the Skype Peer ton Peer Internet Telephony Protocol (English, pdf)
• Markus Daehne: Skype ME from single user ton of Small Enterprise and Beyond. Syngress Media, U.S., 2005, 350 sides, English, ISBN 1-597-49032-6

Related links

• German Skype Website
• German Skype Blog

Sources

Articles in category "Skype"

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Related Websites

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