Synchronization Standard – Physical Interconnection for Ethernet-Based Timing Distribution
|Publication Date:||1 April 2009|
This standard addresses the interconnection between the Timing
Signal Generator (TSG) and Network Elements (NE) in an
The Ethernet signals considered here belong to the Fast Ethernet and Gigabit Ethernet categories. Both electrical (i.e., utilizing twisted-pair cabling) and optical (i.e., utilizing fiber-optic cabling) signals are considered. The relevant forms of Fast Ethernet included are 100Base-TX, 100Base-FX, 100Base-SX, and 100Base-BX. The relevant forms of Gigabit Ethernet included are 1000Base-T, 1000Base-LX, 1000Base- SX, and 1000Base-BX10.
Higher layer protocols, formats, and methods that make the Ethernet signal suitable for timing are not within the scope of this standard, but indicated in Annex A for information. These include Precision Time Protocol (PTP), Network Time Protocol (NTP), and Synchronous Ethernet. The standard does not preclude the development of enhancements or additional protocols provided the physical layer connectivity comply with the requirements provided herein.
Protection (e.g., lightning) is out of the scope of this document.
The standard does not render timing distribution methods based on prevailing twisted-pair cabling (e.g., DS1, composite-clock or CC) obsolete or irrelevant.