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Open Phone Abstraction Library
In the field of VoIP networking, the Open Phone Abstraction Library (OPAL) continues the open-source openh323 project to support a wide range of commonly used protocols used to send voice, video and fax data over IP networks rather than being tied to the H.323 protocol. Initially, from 2007, OPAL supported the H.323 and Session Initiation Protocol (SIP) protocols, but it has grown to include Asterisk IAX2. About OPAL implements a wide range of Voice over IP (VoIP) protocols for voice, video and fax data over IP networks. It is written in C++ and released under the Mozilla Public Licence. OPAL utilises the PTLib portable library that allows OPAL to run on a variety of platforms including Unix/Linux/BSD, MacOSX, Windows, Windows mobile and embedded systems. Opal was developed as a derivative of the OpenH323 library. Applications OPAL is used by the open source Video Conferencing Program Ekiga Ekiga (formerly called GnomeMeeting) is a VoIP and video conferencing applicatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Voice Over IP
Voice over Internet Protocol (VoIP), also called IP telephony, is a method and group of technologies for voice calls for the delivery of voice communication sessions over Internet Protocol (IP) networks, such as the Internet. The broader terms Internet telephony, broadband telephony, and broadband phone service specifically refer to the provisioning of voice and other communications services ( fax, SMS, voice messaging) over the Internet, rather than via the public switched telephone network (PSTN), also known as plain old telephone service (POTS). Overview The steps and principles involved in originating VoIP telephone calls are similar to traditional digital telephony and involve signaling, channel setup, digitization of the analog voice signals, and encoding. Instead of being transmitted over a circuit-switched network, the digital information is packetized and transmission occurs as IP packets over a packet-switched network. They transport media streams using special medi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Open-source Model
Open source is source code that is made freely available for possible modification and redistribution. Products include permission to use the source code, design documents, or content of the product. The open-source model is a decentralized software development model that encourages open collaboration. A main principle of open-source software development is peer production, with products such as source code, blueprints, and documentation freely available to the public. The open-source movement in software began as a response to the limitations of proprietary code. The model is used for projects such as in open-source appropriate technology, and open-source drug discovery. Open source promotes universal access via an open-source or free license to a product's design or blueprint, and universal redistribution of that design or blueprint. Before the phrase ''open source'' became widely adopted, developers and producers have used a variety of other terms. ''Open source'' gained ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Openh323
The OpenH323 project had as its goal the development of a full featured, open source ( MPL) implementation of the H.323 Voice over IP protocol. The code was written in C++ and, through the development effort of numerous people around the world, supported a broad subset of the H.323 protocol. The software has since been integrated into a number of open source and commercial software products. The project was forked into two new projects in October 2007. Each of these projects has a different focus: * The Open Phone Abstraction Library (OPAL) project continued the architectural development of OpenH323 with the goal of integrating additional VoIP protocols such as SIP and IAX2 changing the API considerably. * The H323Plus project continued the expansion of the support for H.323 as well as support for existing OpenH323 applications. History Initial work commenced on OpenH323 in 1998, although the underlying abstraction library (then called PWLib, now called PTLib) had been in existen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Internet Protocol
The Internet Protocol (IP) is the network layer communications protocol in the Internet protocol suite for relaying datagrams across network boundaries. Its routing function enables internetworking, and essentially establishes the Internet. IP has the task of delivering packets from the source host to the destination host solely based on the IP addresses in the packet headers. For this purpose, IP defines packet structures that encapsulate the data to be delivered. It also defines addressing methods that are used to label the datagram with source and destination information. IP was the connectionless datagram service in the original ''Transmission Control Program'' introduced by Vint Cerf and Bob Kahn in 1974, which was complemented by a connection-oriented service that became the basis for the Transmission Control Protocol (TCP). The Internet protocol suite is therefore often referred to as ''TCP/IP''. The first major version of IP, Internet Protocol version 4 (IPv4), is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Session Initiation Protocol
The Session Initiation Protocol (SIP) is a signaling protocol used for initiating, maintaining, and terminating communication sessions that include voice, video and messaging applications. SIP is used in Internet telephony, in private IP telephone systems, as well as mobile phone calling over LTE (VoLTE). The protocol defines the specific format of messages exchanged and the sequence of communications for cooperation of the participants. SIP is a text-based protocol, incorporating many elements of the Hypertext Transfer Protocol (HTTP) and the Simple Mail Transfer Protocol (SMTP). A call established with SIP may consist of multiple media streams, but no separate streams are required for applications, such as text messaging, that exchange data as payload in the SIP message. SIP works in conjunction with several other protocols that specify and carry the session media. Most commonly, media type and parameter negotiation and media setup are performed with the Session Description ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IAX2
Inter-Asterisk eXchange (IAX) is a communications protocol native to the Asterisk private branch exchange (PBX) software, and is supported by a few other softswitches, PBX systems, and softphones. It is used for transporting VoIP telephony sessions between servers and to terminal devices. The original IAX protocol is deprecated and has been superseded by a second version, commonly called IAX2. The IAX2 protocol was published as an informational (non-standards-track) RFC 5456 by discretion of the RFC Editor in February 2010. Basic properties IAX is a VoIP protocol that can be used for any type of streaming media including video, but is mainly designed for IP voice calls. IAX uses a single User Datagram Protocol (UDP) data stream between endpoints for both the session signaling and the media payloads. Thus it uses only a single UDP port number, typically 4569. This feature provides benefits for traversing network address translators on network boundaries, as it simplifies fir ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Voice Over IP
Voice over Internet Protocol (VoIP), also called IP telephony, is a method and group of technologies for the delivery of speech, voice communications and multimedia sessions over Internet Protocol (IP) networks, such as the Internet. The terms Internet telephony, broadband telephony, and broadband phone service specifically refer to the provisioning of communications services (voice, fax, Short Message Service, SMS, voice-messaging) over the Internet, rather than via the public switched telephone network (PSTN), also known as plain old telephone service (POTS). Overview The steps and principles involved in originating VoIP telephone calls are similar to traditional digital telephony and involve signaling, channel setup, digitization of the analog voice signals, and encoding. Instead of being transmitted over a circuit-switched network, the digital information is packetized and transmission occurs as IP packets over a packet-switched network. They transport media streams using spec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mozilla Public Licence
The Mozilla Public License (MPL) is a free and open-source weak copyleft license for most Mozilla Foundation software such as Firefox and Thunderbird The MPL license is developed and maintained by Mozilla, which seeks to balance the concerns of both open-source and proprietary developers; it is distinguished from others as a middle ground between the permissive software BSD-style licenses and the General Public License. So under the terms of the MPL, it allows the integration of MPL-licensed code into proprietary codebases, but only on condition those components remain accessible. MPL has been used by others, such as Adobe to license their Flex product line, and The Document Foundation to license LibreOffice 4.0 (also on LGPL 3+). Version 1.1 was adapted by several projects to form derivative licenses like Sun Microsystems' Common Development and Distribution License. It has undergone two revisions: the minor update 1.1, and a major update version 2.0 nearing the goals of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
OpenH323
The OpenH323 project had as its goal the development of a full featured, open source ( MPL) implementation of the H.323 Voice over IP protocol. The code was written in C++ and, through the development effort of numerous people around the world, supported a broad subset of the H.323 protocol. The software has since been integrated into a number of open source and commercial software products. The project was forked into two new projects in October 2007. Each of these projects has a different focus: * The Open Phone Abstraction Library (OPAL) project continued the architectural development of OpenH323 with the goal of integrating additional VoIP protocols such as SIP and IAX2 changing the API considerably. * The H323Plus project continued the expansion of the support for H.323 as well as support for existing OpenH323 applications. History Initial work commenced on OpenH323 in 1998, although the underlying abstraction library (then called PWLib, now called PTLib) had been in existen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ekiga
Ekiga (formerly called GnomeMeeting) is a VoIP and video conferencing application for GNOME and Microsoft Windows. It is distributed as free software under the terms of the GNU GPL-2.0-or-later. It was the default VoIP client in Ubuntu until October 2009, when it was replaced by Empathy. Ekiga supports both the SIP and H.323 (based on OPAL) protocols and is fully interoperable with any other SIP compliant application and with Microsoft NetMeeting. It supports many high-quality audio and video codecs. Ekiga was initially written by Damien Sandras in order to graduate from the University of Louvain (UCLouvain). It is currently developed by a community-based team led by Sandras. The logo was designed based on his concept by Andreas Kwiatkowski. Ekiga.net was also a free and private SIP registrar, which enabled its members to originate and terminate (receive) calls from and to each other directly over the Internet. The service was discontinued at the end of 2018. Features Feature ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
