Cabletron Systems HSIM-W87 manual

WAN Terms and Acronyms

PLB — Payload Loop Back, ESF loopback including the facilities datalink.

Point of Presence — The point between the carrier provided equipment and services and the customer provided equipment and services.

PPP— Point-to-Point Protocol, provides a method for transmitting datagrams over serial point-to-point links.

PRI — Primary Rate Interface, an ISDN service providing 23 “B” (Bearer) channels of 64 Kbps and one 64 Kbps “D” (Data) channel for signaling and control.

PVC — Permanent Virtual Circuit, a virtual circuit that provides the equivalent of a dedicated private line service.

Q.933-A — Q.933 Annex A, an ITU link management protocol specification used in Frame Relay.

RAI — Remote Alarm Indicator, is declared in C-bit Parity DS3 applications, after detecting the Yellow Alarm Signal on the alarm channel.

SDLC — Synchronous Data Link Control, layer 2 (link layer) protocol developed by IBM for SNA connectivity. Basis for HDLC.

SEFS — Severely Errored Framing Seconds, is a second with one or more OOF errors or a detected incoming AIS.

SNA — Systems Network Architecture, data communication network architecture developed by IBM in the 1970’s.

T1 — A Bell System term that refers to the physical carrier, or system of transmission media and regenerators, used to transmit a digital signal at 1.544 Mbps.

T1.617-D — T1.617 Annex D, an ANSI link management protocol specification used in Frame Relay.

TDM — Time Division Multiplexing, a technique in which separate data or voice signals are transmitted simultaneously over a single communications medium based on time interleaving.

Timeslot — A standard 64,000 bit/second channel. Synonymous with DS0 (Digital Signal, level 0).

HSIM-W87 User’s Guide C-5