ABSTRACT: GR-303 describes the Telcordia view of the overall system functions and performance levels required when a Digital Loop Carrier System (DLC) is integrated into a Local Digital Switch (LDS). It further describes a generic interface, one particular means of interfacing a DLC Remote Digital Terminal (RDT) with the LDS.

The proposed overall system requirements for Integrated Digital Loop Carrier (IDLC) systems are expressed in terms of functions, i.e., what the combination of RDT and LDS must do when connected together. These end-to-end system requirements are grouped into functional categories dealing with (1) Customer services, (2) Digital network interfaces, (3) Operations Systems interfaces, (4) Craft interfaces, and (5) Overall system capabilities. These proposed requirements do not specify or imply any specific supplier implementation. They are, therefore, termed generic system requirements.

This GR also defines optional features that might be offered in IDLC systems tailored to meet specific applications. Where appropriate, this GR defines the application(s) for which each option is intended. However, these intended applications should only be considered as possible guidelines, and by no means are exhaustive.

The Generic IDLC Interface, between the end components of the system, is defined in a layered structure. These include the physical layer corresponding to an electrical (DS1) or optical (OC-3) signal, the data link layer as a particular communication data link protocol, and the application layer as particular message sets for both operations and call processing. Section 12 of this GR deals with a DS1-based interface. Section 13 (formerly TR-NWT-000303, Supplement 1) provides the generic requirements for interfacing an RDT to an LDS via the Synchronous Optical Network (SONET) format.

The Generic IDLC Interface requirements are consistent with the end-to-end system requirements and comprise one particular means of accomplishing those system requirements. The Generic IDLC Interface requirements also contain options, both in implementation and tied to optional system features. These options are described so that the decision of an RDT supplier to either offer or not offer an option does not preclude the interconnection with another supplier's LDS. While this encourages the development of RDTs tailored for specific applications, it does require the LDS interface to be broad enough to handle a variety of combinations of RDT features. An Integrated Digital Loop Carrier (IDLC) system is a composite system that consists of an RDT and an Integrated Digital Terminal (IDT), which is an integral part of the LDS. The distinguishing characteristic of IDLC systems from Universal DLC (UDLC) systems is the absence of a Central Office Terminal (COT).

This document identifies features and functions that, in the Telcordia view, should be incorporated into IDLC systems to maximize the benefits of IDLC deployment.

Issue 4 of GR-303 includes changes to Sections 1, 3, 4, 5, 6, and 12, and includes additional requirements, text changes, and modification of some existing requirements.

This document replaces SR-3371 and TR-NWT-000303.

Issue 4 of GR-303, Integrated Digital Loop Carrier System Generic Requirements, Objectives, and Interface, replaces Issue 3.

The following documents were fully or partly replaced by GR-303: TR-NWT-000303, TR-NWT-000303-SUP01, TR-NWT-000303-SUP02, TR-TSY-000668, TR-TSY-000670, and TR-TSY-000673.

When using GR-303, you may need to refer to GR-57, GR-253, GR-303-IMD, GR-436,GR-454, GR-474, GR-478, GR-485, GR-499, GR-506, GR-507, GR-511, GR-512, GR-520, GR-528, GR-561, GR-677, GR-679, GR-818,GR-819, GR-20, TR-TSY-000821, GR-823, TR-TSY-000827, GR-828, TR-TSY-000829, TR-TSY-000830, GR-1089, GR-1230, GR-1244, GR-1400, GR-2833, MDP-326-140, SR-3581, ANSI T1, 401, ANSI T1.405, ANSI T1.508, ISO/IEC 9595 and 9596-1 and/or ITU-TG.711.

This GR also includes one or more Issue List Reports (ILRs) that details open or closed technical issues in the main document. The ILR(s) are automatically sent free of charge to the GR document purchaser.