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Glossary of Terms

ADSL ADSL (Asymmetrical Digital Subscriber Line) technology enables existing phone lines to transmit data at a high bandwidth. ADSL technology is an "always on", continuous connection which allows you to use the same phone line for voice or fax while simultaneously using the internet. ADSL is asymmetric because it allows you to download data at a faster rate (up to 6Mb per second) than you can upload, which makes it useful for viewing video and other multimedia files.

ATM
Asynchronous Transfer Mode - a communications protocol which divides a stream of digital data into discrete packets, each of which consists of information plus an address. ATM can be used to transmit mixed voice, data and video information at varying rates.

Bandwidth
Measured in bits-per-second, the maximum amount of data that can flow through an Internet connection.

Capacity
The highest (reliable) transmission speed that can be carried on a channel, circuit or piece of equipment. Capacity may be expressed as raw speed or raw throughput.

Connection
A point-to-point dedicated or switched communications path.

Fixed voice
Telephone calls made to or from a static - rather than mobile - telephone. Hence, a home connection is a "fixed voice" connection.

Internet The Internet is a global system of telephone, cable and data networks. It is a network of networks. It enables commercial organisations, individuals, educational institutions and government agencies to communicate, exchange data and engage in a growing variety of commercial activities in an international, real-time environment.

IP
Internet Protocol - a connectionless, best effort packet switching protocol, which provides routing, fragmentation and reassembly through the data link layer.

ISDN
Integrated Services Digital Network. This is a digital data protocol which allows the carriage of various services - voice, data and video - on a single integrated network. Telstra's OnRamp service is an example of an ISDN service.

ISP
Internet Service Provider.

Multicasting
mechanism which efficiently delivers video, audio and data streams from one source to many receivers without huge bandwidth requirements on the network and applications server. The stream is duplicated at routers throughout the network and can be transmitted to a potentially unlimited number of receivers in a similar way to traditional television and radio broadcast.

PoP
A "point of presence" is a site which provides customers with a point at which to dial in to the Internet.

Point of Interconnect
The point at which calls are transferred from one network to another. Telstra operates 66 points of interconnect - one in each Call Collection Area.

PSTN
Public Switched Telephone Networks. The conventional network on which telephone calls are made.

Internet The Internet is a global system of telephone, cable and data networks. It is a network of networks. It enables commercial organisations, individuals, educational institutions and government agencies to communicate, exchange data and engage in a growing variety of commercial activities in an international, real-time environment.

Router
A special-purpose computer (or software package) that handles the connection between two or more computer networks. Routers look at the destination addresses of the packets of data passing through them and decide which route to send them on.

SS7
Signaling system 7. A signaling system, based on standards set by the International Telecommunications Union, for the transfer of messages between entities in telecommunications networks that enables the setting up, routing and clearing of calls and the transfer of other relevant information relating to the operation of these networks. Signaling System 7 is used for the transfer of such messages between different networks as well as within individual networks.

Switch
A device which allows the connection of circuits based on information provided by the device seeking to establish a circuit.

Unified Messaging
Refers to the combining of various types of messaging (such as e-mail, voice-mail, fax and paging) into a single unified suite. Typically unified messaging will allow you to read faxes as e-mail and hear e-mail read to you over the phone as if it was voice mail.

Virtual PBX
By deploying internet telephones and a computer server running software to control telephone calls a business may enjoy all the functions of a PABX (Private Automatic Branch Exchange) telephone system without having to own a PABX. The IP telephone solution is thus a "Virtual" PABX.

Virtual Private Networks (VPN)
Network resources provided to users, on demand, by public carriers such that the users view this partition of the network as a private network.

VLAN
A Virtual Local Area Network is a network of computers which function as if they were connected to the same network, even though they may be located in physically separate locations. VLAN's are configured using software, and can be mapped according to department, type of user, or primary application, rather than by geography. VLAN's offer flexibility to network administrators - workstations can move location without reconfiguration of their hardware.

VoIP
Voice over Internet Protocol - use of IP to allow telephony over the Internet. Internet telephony software compresses the user's voice and packetises it for transmission. These IP packets are treated as ordinary data which is then transmitted over the Internet like any other data packet.