Frame Relay - A technique for transmitting data over a digital network cheaply and efficiently, in a series of frames. It can originate from one or many points of origin, and likewise can be sent to one or many. It is often deployed by multi-national companies to transmit data between Local Area Networks (LAN’s) on the same Wide Area Network (WAN).
G (VoIP A to Z)
Gatekeeper – an entity or software that manages a network or zone. Tasks of the gatekeeper include providing IP address information and translation, as well as other services, both to terminals and endpoints within this network, and to gatekeepers in other networks.
H (VoIP A to Z)
H.323 - this is the ITU-T recommendation for defining the protocols to carry voice and data communications over a packet network. More on H.323
I (VoIP A to Z)
IP – Click here
IP Address – Click here
ITU-T – The International Telecommunications Union Standardization Sector is responsible for developing and maintaining standards on behalf of the ITU. It is a group that are based in Geneva, Switzerland.
IP Centrex - Centrex refers to a ‘Central Exchange’. It is a type of switching that works from a central headquarters rather than from the customers’ premises. The equipment is managed by the Service Provider, who would typically provide a range of managed services.
IP Gateway - The purpose of an IP Gateway (or Media Gateway) is to translate data from one telecommunications network in order for it to pass on a different type of network. For example, an IP Gateway sits between the PSTN and an IP network in order to ensure that traffic can pass between these networks, ie. Converting a call from a PSTN phone into a format so it can be passed on IP.
IP Phone - A device used to make a call over IP (a voice over IP call). The phone will convert your voice stream into discrete packets to be sent over an IP network, as opposed to traditional telephones which run on circuit switched networks.
ISP - An Internet Service Provider is a company that offers access to the Internet through its facilities. A few years ago this type of activity was confined to major telecommunications providers, though nowadays there are many providers in the market offering this service, with different add-ons such as web hosting an e-mail services.
ISDN - Integrated Services Digital Network – this is a traditional type of network that runs on copper lines and allows digital signals to be carried with greater speed and efficiency than traditional analogue signals. ISDN used to be the alternative for businesses and individuals who wanted to transmit large volumes of data at greater speeds than their own phone lines allowed. However, it has been largely replaced by more modern broadband technologies.
ISUP - This refers to ISDN User Part. When a call is made on a traditional telephone system, a large number of exchanges may be involved in passing that call to its destination. ISUP messages are used by one exchange switch to signal to the next switch, carrying information such as calling party number. It is specified by the ITU-T under the Q.7XX series.
J-K (VoIP A to Z)
Jitter - An abrupt or unwanted variation in the characteristics of a signal. For example, the gap between successive pulses. This will cause a distortion in the sound noticeable by the person being called.
L- VoIP A to Z
LAN - Local Area Network – this is just a series of machines all connected onto the same mini-network. It may be telephones, PC’s, wireless devices and other peripherals. LAN’s are traditionally thought of as an corporate-type local network. However, nowadays, more and more people are setting up their own LAN’s in the home.
LCR - Least Cost Routing is a method used by telecoms service providers of routing their traffic to its destination at the lowest cost. This is usually in the form of a table displaying the cheapest to the most expensive carriers for that traffic. This information is then programmed into the switches and traffic is routed accordingly. In practice, most operators, except those at the true minimum cost end of the market, will route based on a mix of cost and quality, to ensure their customer satisfaction.
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