Colocation Defined
Colocation Glossary Index
For definitions associated with co-location and datacentres, please browse the glossary of terms below.
Packet
A sub-unit of a data stream; a grouping of information that includes a header (containing information like address destination) and, in most cases, user data.
Packet Switched Network
Network that does not establish a dedicated path through the network for the duration of a session, opting instead to transmit data in units called packets in a connectionless manner; data streams are broken into packets at the front end of a transmission, sent over the best available network connection, and then reassembled in their original order at the destination endpoint.
Packet Switching
A switching system that uses a physical communications connection only long enough to transit a data message; data messages are disassembled into packets and reassembled at the receiving end of the communication link; packets may travel over many diverse communications links to get to the common endpoint. This is most often contrasted with circuit switching in data communications, where all data messages transmitted during a session are transmitted over the same path for the duration of the session.
Pay-Per-View
In the cable television industry, the ability to view programming on a pay per play basis.
PBX
Originally PBX was Private Branch Exchange and PABX was Private Automated Branch Exchange, but only the latter now applies. This is a generic term for a switch, a telephone system, that is found inside a company's premises (as opposed to one serving the general public). Automation meant that employees could dial out themselves (by pressing a number, say 9) rather than having to request a line from the switchboard operator.
Peering
A relationship whereby two autonomous networks exchange traffic, generally using BGP protocol.
POTS
Plain old telephone services. A single line telephone service with no frills. You can simply make or receive one call at a time.
Primary Rate Access (PRA)
There are two types of ISDN connection- Basic Rate Access and Primary Rate Access.
With PRA, the user is presented with a minimum of 15 64kbps B channels and one 64kbps-signalling channel known as the D channel. In general PRA carries voice, data and image over optical fibre or digital microwave links. It is generally used by medium to large size organisations who use advanced telephone networks or videoconferencing.
Proprietary
A system or software design which means the system or software may only be compatible with other products from the same vendor.
Protocol
An agreed-upon format for transmitting data between two devices.
PTO
Public Telecommunications Operators.
PTT
Stands for Postal, Telegraph and Telephone company. This is a generic term for the traditional provider of the telephony and mail services in many countries.
Public Switched Telephone Network PSTN
A circuit-switched analogue network which makes connections for the duration of telephone call. These connections are usually used for voice but can also carry data between facsimile machines and computers (via a modem).
