Could you explain stardard: GR-1244 to me?

Title: Clocks for the Synchronized Network: Common Generic Criteria Number: GR-1244-CORE Issue Number: 04 Issue Date: 2009/10/06 Replaces: GR-1244-CORE Issue 03 Addendum: n/a, Bulletin: n/a, Revision: n/a, Supplement: n/a, Volume: n/a Abstract: Issue 4 of GR-1244, Clocks for the Synchronized Network: Common Generic Criteria, replaces Issue 3, and is a component of FR-SONET-01, and FR-TRANSPORT-SYSTEMS-01. 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 Ethernet' applications. 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.

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 standards documents.