IP Performance Metrics (ippm)

Description of Working Group

The IPPM WG has developed a set of standard metrics that can be
applied to the quality, performance, and reliability of Internet data
delivery services. These metrics are designed such that they can be
performed by network operators, end users, or independent testing
groups. It is important that the metrics not represent a value judgment
(i.e. define "good" and "bad"), but rather provide unbiased quantitative
measures of performance.

Functions peripheral to Internet data delivery services, such as NOC/NIC
services, are beyond the scope of this working group.

The IPPM WG has produced documents that define specific metrics and
procedures for accurately measuring and documenting these metrics. This
is the current list of fundamental metrics and the existing set of
derived metrics.

- connectivity
- one-way delay and loss
- round-trip delay.
- delay variation
- loss patterns
- packet reordering
- bulk transport capacity
- link bandwidth capacity
- packet duplication

The working group will advance these metrics along the standards track
within the IETF. The WG will document the process of moving documents along
the standards track, based on draft-bradner-metricstest. As this process
is likely to be needed by other groups as well (in particular BMWG,
PMOL), the group will collaborate with other groups in order to ensure
that there
is consensus amongst all groups expected to use the process.

Additionally, the WG will produce Proposed Standard AS documents,
comparable to applicability statements in RFC 2026, that will focus on
procedures
for measuring the individual metrics and how these metrics characterize
features that are important to different service classes, such as bulk
transport,
periodic streams, packet bursts or multimedia streams. Each AS
document will discuss the performance characteristics that are
pertinent to a specified service class; clearly identify the set of
metrics that
aid in the description of those characteristics; specify the methodologies
required to collect said metrics; and lastly, present the requirements
for the common, unambiguous reporting of testing results. The AS
documents can also discuss the use of the metrics to verify performance
expectations,
such as SLA's, report results to specific user groups or investigate
network problems. The focus is, again, to define how this should be
done, not
to define a value judgment. The WG may define additional statistics for
its metrics if needed. Specific topics of these AS documents must be
approved by the Area Directors as charter additions.

The WG will work on documents describing how to compose and decompose
the results of its metrics over time or space.

The WG has produced protocols to enable communication among test
equipment that implements the one- and two-way metrics (OWAMP and TWAMP
respectively). OWAMP and TWAMP will be advanced along the standards
track. Further
development of these protocols will also be done inside the WG.

The metrics developed by the WG were developed inside an active
measurement context, that is, the devices used to measure the metrics
produce their own traffic. However, most metrics can be used inside a
passive context as well. No work is planned is this area though,
this may be changed with AD approval.

The intent of the WG is to cooperate with other appropriate standards
bodies and forums (such as ATIS IIF, ITU-T SG 12, 13 and 15, MEF) to
promote consistent approaches and metrics. Within the IETF process, IPPM
metrics
definitions will be subject to as rigorous a scrutiny for usefulness,
clarity, and accuracy as other protocol standards. The IPPM WG will
interact with other areas of IETF activity whose scope intersect with
the requirement of these specific metrics. The WG will, on request, provide
input to other IETF WG on the use of these metrics.

Goals and Milestones