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Access to Assured and Accurate Time II: Assuredness of Reference Architectures

NIST and MITRE, with funding from DHS S&T, have been working towards the development of a Conformance Framework applicable to the question of providing the US critical infrastructure access to accurate and assured time.

A Conformance Framework that enables the assessment of assuredness, according to practices and technical definitions that are agreed upon, should allow manufacturers to effectively compare the characteristics of their products among themselves and with respect to the needs of their customers, both system integrators who in turn will provide time to end users, and direct users who need a reliable and accurate timing signal at their premises.

A first workshop, in June 2018, identified a paradigm solution for access to accurate and assured time (the Reference Architecture, featuring a competent processor and a number of diverse timing sources) and produced a set of attributes describing its resilience and the assuredness of the time it delivers.

We later identified three implementation levels for the Reference Architecture, with growing resilience:

  • Level 1- basic: one timing source, likely modernized and multi-constellation GNSS-based;
  • Level 2 – moderate: the same GNSS-based timing source of Level 1, with the addition of a local independent clock;
  • Level 3 and 4 - high: with additional and diverse timing sources (i.e. NTP, PTP over fiber, etc.)

each described by the appropriate set of attributes, and capable of operate in the presence of specific classes of threats.

This one-day workshop has two components: one designed to learn of the implementations of the Reference Architecture that are available on the market, the other designed to stimulate an open discussion of the Conformance Framework as a tool to understand the capabilities of commercial products, with inputs from manufactures and users alike.

“The goal of this workshop is to test the viability of a Conformance Framework as it has been developed so far by collecting feedback from the parties that should function within it, the timing equipment manufacturers and their customers.”


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Created November 23, 2018, Updated April 9, 2019