| Glossary | 
  | PHY  | 
  | 
  | 
PHY | PHY as in physical specifications. OSI Physical Layer, which provides for transmission of  | 
  | cells over a physical medium connecting two ATM devices.  | 
ping | Packet InterNet Grouper. PING is a program used to test whether a particular network  | 
  | destination on the Internet is online (i.e. working) by repeatedly bouncing a "signal" off a  | 
  | specified address and seeing how long that signal takes to complete the round trip. No  | 
  | return signal - site is down or unreachable. Portion is returned - trouble with the connection.  | 
PLAR | Private Line, Automatic Ringdown. A leased voice circuit that connects two single  | 
  | instruments together. When either handset is lifted, the other instrument automatically  | 
  | rings.  | 
PPP | |
  | preestablished WAN communications path from the customer premises, through a carrier  | 
  | network (the telephone company), to a remote network  | 
PPPoDS0  | |
PRACK | Provisionable acknowledgement.  | 
Primary Rate Interface  | The ISDN equivalent of a T1. The Primary Rate Interface (delivered to the customer’s  | 
(PRI) | premise) provides 23B+D (N.America) or 30B+D (Europe) running at 1.544 Mb/sec and  | 
  | 2.048 Mb/sec, respectively.  | 
protocol  | Procedure or set of rules.  | 
PVC | Permanent Virtual Circuit. A PVC is a permanent channel connection between two ATM  | 
  | devices. PVC’s allow network transmissions to be started without having to first establish  | 
  | a connection with the end point ATM device. When a PVC is constructed, the end points  | 
  | of the connection will agree upon a path in which data will travel, and therefore agree upon  | 
  | the route that data will travel to reach its destination.  | 
Quality of Service (QoS)  | The measure of the telephone service quality provided to a subscriber.  | 
RADIUS | Remote Authentication   | 
  | software system. The software supports remote access applications, allowing an  | 
  | organization to maintain user profiles in a centralized database residing on an  | 
  | authentication server which can be shared by multiple remote access servers.  | 
robbed bit | A type of analog signaling that will occasionally steal information bits used for circuit  | 
  | signaling coding.  | 
router | A computer or internet working device that directs traffic and moves packets between  | 
  | networks. A hardware architecture used in LANs, MANs, WANs, the Internet and  | 
  | Intranets. A device that connects any number of LANs. Routers use headers and a  | 
  | forwarding table to determine where packets go, and they use ICMP to communicate with  | 
  | each other and configure the best route between any two hosts.  | 
Adit 3104 - Release 1.6  |