VoIP gateway

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A VoIP gateway is an electronic device or system that converts traditional telecommunication interfaces into IP telephony (VoIP) interfaces. So z. B. a VoIP gateway converts the ISDN interfaces of a telephone system into IP interfaces with Session Initiation Protocol (SIP). The user is thus able to swivel his existing telephone system in the direction of IP telephony without having to upgrade or renew the existing technology.

The gateway converts the conventional voice signals required for the send and receive voice communication into IP data packets . It can also be thought of as a kind of protocol converter.

The general term gateway comes from English, is ambiguous and means "gate way" or "entrance". There are a variety of these devices. The most common type of use is in telecommunications.

Technology and guidelines (coding)

Various network packets are forwarded by first decoding each individual packet into individual protocol layers and then encoding it again according to the recipient's protocol. The gateway thus represents a (virtual) node that belongs to both networks and handles the cross-network data traffic.

Gateways use different codes (guidelines) for data transmission. G.711 is one of many codings for IP telephony (VoIP) and is used in ISDN. The voice quality of a VoIP phone call with G.711 therefore corresponds to that of ISDN. In the classification of the Mean Opinion Score (MOS), G.711 achieved a value of 4.4. The MOS determines the subjective perception of the speech quality of a user. G.711 thus achieves a higher subjective voice quality than most other codecs, such as G.726 and G.729 . These have the advantage that a lower data transmission rate is required due to data compression .

Video conferencing

Video conferencing systems based on ISDN require several ISDN S0 interfaces because of the high data transmission rate required in order to be able to transmit the picture and sound information in sufficient quality. In the age of DSL flat rates, it is therefore advisable to convert these ISDN interfaces from the video conference system into IP interfaces in order to then transfer them via IP. When it arrives at the recipient, this information is converted back into ISDN interfaces using a second VoIP gateway and connected to the recipient's video conference system. In this way, video conferences can be carried out with the systems already in place, while at the same time reducing connection charges considerably.

Since the introduction of VoIP has already begun on a broad front, z. For example, when using Cisco call managers, there is sometimes the problem that existing devices with ISDN interfaces cannot be integrated. The required ISDN interfaces can thus be generated by using VoIP gateways.

Web links

Individual evidence

  1. ↑ Dimaweb mini dictionary - What is a VoIP gateway - description . Dimaweb website, accessed November 14, 2013