Welcome to GdotWhat?

Your guide to Sync standards and how to interpret them

Various Standardization Development Organizations (SDOs) have been working at standards dealing with synchronisation.

Within Telecoms, the main group dealing with synchronisation is Question 13 in ITU-T SG15. Starting from end application requirements as defined for instance by 3GPP for mobile applications, over the years Q13 has delivered a number of Recommendations dealing with network synchronization solutions, network synchronisation performance requirements, clock performance, PTP (Precision Time Protocol) telecom profiles.

PTP (Precision Time Protocol) has been specified by IEEE 1588 WG. P1588 WG is working at several Amendments to the IEEE1588-2019 Standard.

Several other IEEE WGs are working at synchronisation. In particular, IEEE 802.1 WG has developed and is maintaining IEEE 802.1AS Standard, Timing and Synchronization for Time-Sensitive Applications. This is a PTP profile that can be used for Industrial Automation or Automotive applications.

The O-RAN Alliance has developed a number of synchronization specifications related to the open radio access network.

Right now, we mainly cover the ITU-T and O-RAN Standards. We will be adding material from other standards bodies in the near future.

An overview on O-RAN synchronization is available in the O-RAN Synchronization page. The starting point for learning about the ITU-T synchronisation standards is ITU-T Packet-Based Synchronisation - A Guide to the Synchronisation Standards.

Alternatively, you can search for the content you want using the search bar below, go directly to the topic you want from the list of featured pages or browse the table of contents to see what is available.

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Key:	Device Test	Network Test

What are you testing?	Standard	Technical Overview		Test Guide
	General	CX7006	PTP Profile Compliance: The key to network timing interoperability
		CX5013	Time and Time Error, A Guide to Network Synchronisation
			Interpretation of Time Error Results
Frequency Network Limits	G.8261.1			CX5018	Sentinel Field Test Plan for Frequency Synchronisation using PTP
SyncE Clock	G.8262	CX3002	Jitter and Wander in SyncE: Testing Jitter and Wander to ITU-T Standards	CX5001	G.8262 SyncE conformance testing: Proving SyncE compliance to ITU-T G.8262 using Paragon-X
SyncE Clock	G.8262	CX8010	The importance of measuring wander on high speed interfaces	CX5026	Testing EECs to ITU-T G.8262 using Paragon-100G
Time and Phase Network Limits	G.8271.1			CX5019	Sentinel Field Test Plan for TDD-LTTE/LTE-A Synchronisation using PTP
Time and Phase Network Limits	G.8271.2			CX4005	Sentinel Field Test Plan for TDD-LTE/LTE-A Synchronisation in Systems using Assisted Partial Timing Support and Partial Timing Support
Boundary and Slave Clock	G.8273.2	CX6001	Testing a T-BC to ITU-T G.8273.2	CX5008	T-BC Time Error: Testing Boundary Clocks to ITU-T G.8273.2 using Paragon-X
		CX6002	Measuring Time Error Transfer of G.8273.2 T-BCs	CX3003	PTP Time Error for T-BC: Testing Boundary Clocks to ITU-T G.8273.2 using Paragon-100G
				CX5020	T-TSC Time Error: Testing Time Slave Clocks to ITU-T G.8273.2 using Paragon-X
Transparent Clock	G.8273.3			CX5021	T-TC Time Error: Testing Transparent Clocks to ITU-T G.8273.3 using Paragon-X
Time-Aware Relay	IEEE802.1AS (gPTP)	CX7005	gPTP: Proving Time Accuracy for Automotive Systems	CX5030	Time Aware Relay: Time Error Testing using Paragon-X
Time-Aware Relay	IEEE802.1AS (gPTP)	CX7003	gPTP: Testing Synchronisation for Industrial TSN

Welcome to GdotWhat?

Your guide to Sync standards and how to interpret them

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