Overview of VoIP-telephony network as an example SIPNET
On TV screens and in subway cars have lured advertising companies offering supposedly cheap international calls. Alas, it is a deception to neprosvyaschennyh – landline rapidly losing ground to mobile communications. Even cellular networks – the top high cost compared to the new trend of the Internet. VoIP is here. And it grows.
Mysterious Beast VoIP
VoIP is nothing like internet telephony. Simply put, this technology is broadcast live voice over internet from computer to computer: how to connect to a computer microphone and speakers, to install the program – and make calls to other computers to communicate voice on the phone.
VoIP stands for reduction Voice over Internet Protocol (Voice over IP). With VoIP-communication analog signal from a microphone is encoded into a digital data stream, which is then routed to the right destination. The remote computer is back scheme – a digital stream is decoded into an analog signal and is played through speakers or headphones.
Transmission of analog audio via the network was first produced back in 1993, but the commercialization of this technology arose only after ten years. Users are tired pound on the keyboard to communicate with loved ones alive are interested in live to hear your virtual interlocutor. Completely free of charge, whether he even on another continent. To do this, just something I had to install a small client software, and then phoning friends. With time, the VoIP-network users the opportunity to make calls from your computer directly to landlines – now with headphones you can hear not only the voice of a friend, and grandfather of the distant village. Learn more about voice over ip.
These calls are made is not free, but at very low rates. In any case, a call from VoIP to PSTN network is much smaller than the classic long-distance and international calls. VoIP systems have all the chances in the future “outdo” his old colleague – classic phone.
SIP – not only NET
SIP (Session Initiation Protocol) – a protocol to establish an interactive session between users, including the transmission of text, audio and video data. SIP was approved in November 2000 and is a “competitor” of another VoIP-Protocol – H.323. SIP clients use to communicate with port 5060 TCP and UDP (remember, if you konfigurirvat firewall). As such, SIP establishes a connection between users, but the transmission of audio and video is a Real-time Transport Protocol (RTP).
Incidentally, the same Skype uses its own unique protocol, so to use this network, you must only “native” software. SIPNET also supported any programs and devices that can work with SIP.
SIP is not Skype, Skype is not SIP
In just a couple of years on the Skype network learned at least all. The first successful commercial introduction, the global popularity, the frenzied pace of development. Users around the world for the first time were able to easily voice communication over the Internet. Most of Skype was entertaining people it as a free service – phone calls from computer to computer were new, about any landline calls, no one thought, even though this possibility.
Over time, Skype competitors began to appear, and the difference between them and the VoIP-forerunner was one thing, but substantial – on the technological level. The fact that the technology VoIP refers to the ability of users to connect to different protocols. For example, Skype uses a proprietary protocol and closed, and most of the other networks are built on an open protocol SIP.