Saturday, September 16, 2006
VoIP's Terms in Wikipedia
VoIP - Voice over IP
Voice over Internet Protocol, also called VoIP, IP Telephony, Internet telephony, Broadband telephony, Broadband Phone and Voice over Broadband is the routing of voice conversations over the Internet or through any other IP-based network.
Protocols which are used to carry voice signals over the IP network are commonly referred to as Voice over IP or VoIP protocols. They may be viewed as commercial realizations of the experimental Network Voice Protocol (1973) invented for the ARPANET.
VoIP - Voice over IP
Mobile VoIP - Mobile Voice over IP
Mobile VoIP or 'mobile voice over Internet Protocol' is an extension of the voice over IP technology and service. It puts wings on the classic approach of VoIP.
Mobile VoIP is more than Voice over WiFi or VoWiFi. Using any broadband IP-capable wireless network connection mobile VoIP will be an application over other networks such as EVDO rev A (which is synchronously high speed - both high speed up and down), HSDPA or potentially WiMax. Mobile VoIP will enable further economic and mobility tradeoffs. For example, Voice over WiFi offers free service but is only available within the coverage area of the WiFi Access Point. High speed services from mobile operators using EVDO rev A or HSPDA with probably have better audio quality and capabilities for metropolitan-wide coverage including fast handoffs from mobile base station to another, yet it will cost more than the typical WiFi-based VoIP service.
By mid-2006, there are an estimated 70 million users of Skype - a PC to PC service for voice communications over the Internet Protocol and some 20 million users of gateway-to-gateway voice over IP services such as Vonage, and there are a billion users of mobile phone users around the world.
Mobile VoIP - Mobile Voice over IP
VoWLAN - Voice over Wireless LAN
VoWLAN (Voice over Wireless LAN) is the use of a wireless broadband network for the purpose of vocal conversation. In other words, it's just like VOIP but over a Wi-Fi network. VoWLAN can be conducted over any internet accessible device, including a laptop, PDA or the new VoWLAN units which look and function like cellphones. VoWLAN's chief advantages to consumers are cheaper local and international calls, free calls to other VoWLAN units and a simplified integrated billing of both phone and Internet service providers.
At this point VoWLAN is not popular because of a lack of wireless coverage area. So, many VoWLAN service providers have been distributing cellphones with dual wireless and GSM modes.
Although VoWLAN and 3G have certain feature similarities, VoWLAN is different in the sense that it uses a wireless internet network (typically 802.11) rather than a cellphone network.
VoWLAN - Voice over Wireless LAN
SIP - Session Initiation Protocol
The Session Initiation Protocol (SIP) is an application-layer control (signaling) protocol for creating, modifying, and terminating sessions with one or more participants. These sessions include Internet telephone calls, multimedia distribution, and multimedia conferences." (cit. RFC 3261). It was originally designed by Henning Schulzrinne (Columbia University) and is specified in the RFC 3261 of the IETF SIP Working Group. In November 2000, SIP was accepted as a 3GPP signaling protocol and permanent element of the IMS architecture. It is widely used as signaling protocol for Voice over IP, along with H.323 and others.
SIP clients traditionally use TCP and UDP port 5060 to connect to SIP servers and other SIP endpoints. SIP is primarily used in setting up and tearing down voice or video calls. However, it can be used in any application where session initiation is a requirement. These include, Event Subscription and Notification, Terminal mobility and so on. There are a large number of SIP-related RFCs that define behavior for such applications. All voice/video communications are done over separate session protocols, typically RTP.
A motivating goal for SIP was to provide a signaling and call setup protocol for IP-based communications that can support a superset of the call processing functions and features present in the public switched telephone network (PSTN). The SIP Protocol by itself does not define these features, rather, its focus is call-setup and signaling. However, it has been designed to enable the building of such features in network elements known as Proxy Servers and User Agents. As such, these are features that permit familiar telephone-like operations: dialing a number, causing a phone to ring, hearing ringback tones or a busy signal. Implementation and terminology are different in the SIP world but to the end-user, the behavior is similar.
SIP - Session Initiation Protocol
