Liaison statement
For Information: Quality Experience Delivered (Broadband QED) project and Reply to Liaison

The Broadband Forum wishes to thank SG12 for informing us of your work on
harmonizing testing methodology across the industry. We look forward to
cooperating with SG12 on this endeavor.

To this end we would like to inform SG12 of three areas of testing related work
that the Broadband Forum currently has under way:

Quality Experience Delivered (Broadband QED) project -The QED project is
developing a new, Quality Attenuation (ΔQ) method to capture packet network
performance that may be applied to analysis of both deployed networks and in
laboratory testing.

Quality Attenuation (ΔQ) is an approach to systems performance analysis that
has applicability to broadband networks. It uses statistical distributions as a
proxy for quality of experience and application outcomes. ΔQ can decompose a
round trip time into separate constituent components, corresponding to various
sources of performance degradation (packet loss/delay), be they structural
(architecture/design), network dimensioning (link speeds etc.) or network
load/scheduling related. The component elements of ΔQ are composable i.e. they
are both additive within an individual link to give its resultant performance
and can be accumulated along the end-to-end digital delivery chain (e.g.
between user device or CPE and application server in the cloud data center). It
is this mathematical tractability that makes the technique so powerful for
reasoning about systems (network) performance and facilitates “performance by
design”.

This project will develop a comprehensive overview of Quality Attenuation and
its applicability to broadband networks. It will cover the theory, measurement
technique, use-cases and benefits of the approach.

The Broadband Forum is also progressing work on Application-Layer Testing
(ALT), which allows the evaluation of network and application performance in
laboratory testing under conditions which emulate the time-domain traffic
characteristics resulting from the behavior of multiple applications and
subscribers using a system under test. The project is defining an architecture
and requirements for ALT systems and data models to support specification of
unambiguous, reproducible tests that support these complex behaviors. It is
also identifying metrics and measurements where appropriate that directly
characterize application performance, as opposed to network performance. In
addition to application-specific metrics, ALT incorporates network QoS metrics
and measurements such as those currently specified for packet delay, delay
variation and loss. It will also support the metrics and measurements
associated with ΔQ when these are specified.

The Broadband Forum is also progressing work on performance measurement from
the IP edge to customer equipment using STAMP. This allows the measurement of
access and packet transport network performance.

We will keep you appraised of this work as it progresses.

Sincerely,

Lincoln Lavoie,
Broadband Forum Technical Committee Chair