scope:

Purpose and Scope

This standard defines speed, accuracy, dependability, and availability parameters that may be used in specifying and assessing the performance of public frame relay data communication services. The defined parameters apply to end-to-end, point-to-point frame relay connections¹ and to specified portions of such connections when provided in accordance with the American National Standards specified in clause 2.

This standard also defines frame relay service classes with their associated delay and loss parameters, together with allocations to frame relay networks. The frame relay service classes may be used to describe the information transfer phase of data networks when providing national frame relay service (either permanent virtual connection service or switched virtual connection service). Three frame relay performance parameters - frame transfer delay, frame delay jitter, and committed frame loss ratio - are used to characterize the various frame relay service classes.

The performance parameters and frame relay service classes defined in this standard are intended to be used in the planning of national frame relay services. The intended users of this standard include frame relay service providers, equipment manufacturers, and end users. This standard may be used: (1) by service providers in the planning, development, and assessment of frame relay services that meet user performance needs; (2) by equipment manufacturers as performance metrics that will affect equipment design; and (3) by users in evaluating performance.

The scope of this standard is summarized in Figure 1. The frame relay performance parameters are defined on the basis of frame transfer reference events that may be observed at physical interfaces associated with specified boundaries. For comparability and completeness, frame relay performance is considered in the context of the 3x3 performance matrix defined in ANSI X3.102-1992. Three protocolindependent data communication functions are identified in the matrix: (1) access, (2) user information transfer, and (3) disengagement. Each function is considered with respect to three general performance concerns (or "performance criteria"): speed, accuracy, and dependability. An associated two-state model provides a basis for describing permanent virtual circuit (PVC) service availability.

The performance parameters defined in this standard describe the speed, accuracy, dependability, and availability of frame relay networks.

NOTES

0 The parameters defined in this standard may be augmented or modified based upon further study of the requirements of the services to be supported on frame relay networks.

0 The speed, accuracy, and dependability parameters are intended to characterize frame relay connections in the available state.

0 The parameters of this standard are designed to measure the performance of network elements between two section boundaries. However, users of this standard should be aware that the behavior of connection elements outside the pair of boundaries can negatively influence the measured performance of the elements between the boundaries. Examples are described in Annex F.

This standard is organized as follows:

- Clause 2 presents the normative references;

- Clause 3 defines a performance model and a set of frame transfer reference events (FEs) that provide a basis for performance parameter definition;

- Clause 4 defines frame-based speed of service, accuracy, and dependability parameters for the information transfer phase using the FEs defined in clause 3;

- Clause 5 defines quality of services classes for the information transfer phase;

- Clause 6 provides allocation rules for the objectives of the classes of clause 5;

- Clause 7 defines frame-based speed of service, accuracy, and dependability parameters for the access and disengagement phases using the FEs defined in clause 3;

- Clause 8 defines the PVC availability parameters using the primary parameters defined in clause 4;

- Annex A presents a test for judging traffic conformance for performance assessment purposes;

- Annex B defines bit-based accuracy and dependability parameters associated with the transfer of user information in frame relay services;

- Annex C provides a glossary of acronyms;

- Annex D provides information on sampling estimation of the PVC availability parameters;

- Annex E discusses the performance effects of network indications of congestion and makes general recommendations for controlling these effects;

- Annex F identifies effects of external connection elements on measured performance;

- Annex G presents relationships between Frame Relay and ATM performance for Frame Relay PVCs supported by an ATM network; and

- Annex H is the Bibliography.

¹ In the context of this standard, a frame relay connection (denoted hereafter, unless noted otherwise, by the term connection) refers to a virtual connection established between two specified end points.