scope:

This document currently considers the following ATM technology that may be used to support voiceband services:

Digital Signal Processing Unit operating as a Cell Based Echo Canceller;

Interworking Unit (Between ATM and non-ATM Operating Domains);

Multiplexers;

Switches (with digital only interfaces);

Switches (with analog and digital interfaces); and

Transport systems that use ATM technology.

The document is written in the form of a Performance Requirements Document and each section that deals with a particular ATM functional technology operating arrangement is presented as a self standing section. The performance guidelines presented for each functional technology unit must be considered in the context of the end-to-end network of which it is a part. Such performance values will usually be similar to those performance values specified for equipment that does not use ATM technology. When units perform more than one function, the guidelines identified for each function should be met. The list of parameters for which requirements have been provided was obtained from T1 Technical Report No. 46 Table 1. The word "requirement" has a special meaning within the context of this document. As this is a Technical Report, and not a Technical Standard, it does not define requirements in the normal sense. Rather, the term "requirement" in this document should be interpreted to mean, the current recommended provisional value to be used until more formal guidance in the form of a public standard is made available.

The format used to present the requirements is consistent. The parameter is identified first. Parameter definitions are provided in Annex 1 to this document. A discussion section is provided as needed to provide information relevant to the parameter or the parameter threshold. Because each section is intended to be self standing, there will be instances where the same information is repeated in more than one requirements section. For those parameter thresholds that are configuration dependent, a reference is provided to the appropriate section where the pertinent information can be found.

This document assumes that the performance requirements of ITU-T Recommendation I.356 are met on an end to end basis. As a result, a network element can thus be considered to operate error free, from an embedded signal point of view, for any short duration test. Thus, the guidelines were generated on the assumption that there were no cell loss occurrences; no errored cells; no misinserted cells; and switches were adequately designed and traffic loading was controlled so as to ensure there were not lost cells due to CDV or traffic blocking. This assumption used in the generation of these requirements was not intended to imply that these considerations are not important. Rather, that these assumptions are valid for a typical laboratory test evaluation situation. It should be noted that in the context of an operating network, business forces may cause these assumptions to be invalid, however, the degradation which results should not occur due to poor technology, but rather due to provisioning methods and actual traffic loading conditions.

The test set up should not generate errored conditions, e.g. lost or misinserted cells, during compliance testing.

This document recognizes that the current set of guidelines are a subset of a total set of standard tests required to fully evaluate this ATM technology and thus they can be expected to evolve through the addition of new tests to evaluate other aspects of the technology. For example, the current suite of tests do not address how the ATM technology should react to: errored cells; lost cells; and misinserted cells.

This document assumes that these ATM technology devices interface at standard line rates, e.g. DS-1, DS-3, STS-1. The requirements for these interfaces can be found in other ANSI standards and thus these requirements are not contained within this document. Further, the guidelines provided in this document are not contained in the interface standards documents.