T1 ESF CSU ACE Appendix D. Glossary61204025L1-1B © 2004 ADTRAN, Inc 63pingAn internet protocol standard that provides loopback on demand for any device in an IP network. One device“pings” another by sending a loopback request to the device's IP address.point-to-pointType of communications link that connects a single device to another single device, such as a remote terminalto a host computer.PVCpermanent virtual circuit. A frame relay logical link, whose endpoints and class of service are defined by net-work management. Analogous to an X.25 permanent virtual circuit, a PVC consists of the originating framerelay network element address, originating data link control identifier, terminating frame relay network elementaddress, and termination data link control identifier. Originating refers to the access interface form which thePVC is initiated. Terminating refers to the access interface at which the PVC stops. Many data network custom-ers require a PVC between two points. Data terminating equipment with a need form continuous communionuse PVCs. See also DLCI.remote configurationA feature designed into ADTRAN DSU/CSU products that allow remote DSU/CSU to be configured from alocal DSU/CSU or VT100 compatible terminal.routerA device that supports LAN-to-LAN communications. Routers may be equipped to provide frame relay supportto the LAN devices they serve. A frame-relay-capable router encapsulates LAN frames in a frame relay framesand feeds those frame relay frames to a frame relay switch for transmission across the network. A frame-relay-capable router also receives frame relay frames from the network, strips the frame relay frame off each frame toproduce the original LAN frame, and passes the LAN frame on to the end device. Routers connect multipleLAN segments to each other or to a WAN. Routers route traffic on the Level 3 LAN protocol (e.g., the internetprotocol address). See also bridge.