Voice over Internet Protocol (Voice over IP, VoIP) is one of a family of internet technologies, communication protocols, and transmission technologies for delivery of voice communications and multimedia sessions over Internet Protocol (IP) networks, such as the Internet. Other terms frequently encountered and often used synonymously with VoIP are IP telephony, Internet telephony, voice over broadband (VoBB), broadband telephony, and broadband phone.
Internet telephony refers to communications services—Voice, fax, SMS, and/or voice-messaging applications—that are transported via the Internet, rather than the public switched telephone network (PSTN). The steps involved in originating a VoIP telephone call are signaling and media channel setup, digitization of the analog voice signal, encoding, packetization, and transmission as Internet Protocol (IP) packets over a packet-switched network. On the receiving side, similar steps (usually in the reverse order) such as reception of the IP packets, decoding of the packets and digital-to-analog conversion reproduce the original voice stream. Even though IP Telephony and VoIP are terms that are used interchangeably, they are actually different; IP telephony has to do with digital telephony systems that use IP protocols for voice communication while VoIP is actually a subset of IP Telephony. VoIP is a technology used by IP telephony as a means of transporting phone calls.
VoIP systems employ session control protocols to control the set-up and tear-down of calls as well as audio codecs which encode speech allowing transmission over an IP network as digital audio via an audio stream. The codec used is varied between different implementations of VoIP (and often a range of codecs are used); some implementations rely on narrowband and compressed speech, while others support high fidelity stereo codecs.
There are three types of VoIP tools that are commonly used; IP Phones,Software VoIP andMobile Mobile
Internet telephony refers to communications services—Voice, fax, SMS, and/or voice-messaging applications—that are transported via the Internet, rather than the public switched telephone network (PSTN). The steps involved in originating a VoIP telephone call are signaling and media channel setup, digitization of the analog voice signal, encoding, packetization, and transmission as Internet Protocol (IP) packets over a packet-switched network. On the receiving side, similar steps (usually in the reverse order) such as reception of the IP packets, decoding of the packets and digital-to-analog conversion reproduce the original voice stream. Even though IP Telephony and VoIP are terms that are used interchangeably, they are actually different; IP telephony has to do with digital telephony systems that use IP protocols for voice communication while VoIP is actually a subset of IP Telephony. VoIP is a technology used by IP telephony as a means of transporting phone calls.
VoIP systems employ session control protocols to control the set-up and tear-down of calls as well as audio codecs which encode speech allowing transmission over an IP network as digital audio via an audio stream. The codec used is varied between different implementations of VoIP (and often a range of codecs are used); some implementations rely on narrowband and compressed speech, while others support high fidelity stereo codecs.
There are three types of VoIP tools that are commonly used; IP Phones,Software VoIP and
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ReplyDeleteWhat I could understand from here is:
ReplyDeleteIn old days if a computer was suppose to send from Bangalore to Darbhanga, we were sending as a whole unit thru a dedicated vehicle. On destination recipients was getting a product with some scratch (damaged one). So our public switched telephone network (PSTN) was sending analog signal thru dedicated line between source to destination but analog signal is highly prone to noisy signal so getting distorted too much at recipient end. So what they started rather than sending whole computer (Analog signal), let's send it's by parts (Digitalization of analog signal to discrete signal/ 0101...string). Idea was sending parts(bytes)in number of packets. Also parts were not send thru dedicated vehicle (a dedicated connection) but thru number of routes between Bangalore to Darbhanga.It was less expensive as we do not require a dedicated vehicle for whole unit. Recipients was doing same process but reverse i.e. assembling parts to get the computer as a whole unit. That's how we moved from PSTN to IP telephony for cost effective and quality delivery of audio signal. Now people started thinking that though it's ok to send parts
thru various routes to receive high quality deliverable s but whether it's OK to send sensitive item like computer
(Audio/voice signal) with same trasportation rules (Protocol) applicable for sending solid items like bycycle
(less senstive normal data). Definitely not. So they started thinking for special protocol
VoIP ( Session Control Protocol ) better suited than IP protocol. Here one session will be established between source and destibation via available routes.
all voice packets will be sent thru eatablished session. If we will send some packet via one session and some via other then obvoiusly not a user friendly conversation will take place between sender and receiver :-)