Clocks for the Synchronized Network: Common Generic Criteria
Document Number GR-1244
Issue Number 04
Issue Date Oct 2009
Replaces TR-NWT-001244 Issue01
ABSTRACT: The digital synchronization network consists of clocks connected by digital facilities. This document provides criteria that apply to
these various clocks deployed in telecommunications equipment such as transport Network Elements (NEs), Digital Switches, and Timing
Signal Generators (TSGs). Since these clocks can have a critical impact on network performance, GR-1244 may be of significant value to
telecommunications equipment manufacturers (including both synchronization-related component and system manufacturers) and
telecommunications service providers.
The updates in Issue 4 should significantly assist the reader's understanding of the criteria (and expected clock performance
characteristics) in areas such as holdover stability, wander generation, and phase build-out. Specific updates include:
- The equations for calculating fractional frequency offset and drift were corrected, and additional information on the use of
those equations was provided
- The temperature component of the holdover frequency stability requirement for stratum 3 clocks was changed to align with the
corresponding specification in ATIS-0900101
- Significant explanatory test was added regarding the holdover stability curves provided in Section 5
- Additional explanatory text was provided regarding the conditions under which the wander generation requirements apply
- The proposed value of one of the parameters used in defining test cases for testing a clock's phase build-out performance was
changed to reflect the long time constants of the filters used in stratum 2 and 3E clocks
- Additional information was provided regarding the applicability of various criteria to NEs/clocks used in SONET or "synchronous
In addition, minor corrections or clarifications were made in the text in various sections of the document, references to ANSI T1
standards were changed to reflect their reclassification as ATIS standards, and references to the ITU-T documents related to
synchronous Ethernet were added to a number of sections.
Issue 4 of GR-1244, Clocks for the Synchronized Network: Common Generic Criteria, replaces Issue 3.
GR-1244 replaced TR-NWT-001244.
When using GR-1244, you may want to refer to GR-57, GR-63, GR-82, GR-253, GR-378, GR-436, GR-454,
GR-474, GR-487, GR-496, GR-499, GR-820, GR-839, GR-1089, GR-2830, TR-NWT-000170, and various
Components of this product are:
Table of Contents:
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