GdotWhat?

 

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 has released several Amendments to the IEEE1588-2019 Standard, with various enhancements and addressing terminology updates (IEEE1588a, IEEE1588b, IEEE1588c, IEEE1588d, IEEE1588e, IEEE1588g). The group is currently working at a new client-server timing protocol, CSPTP (P1588.1) and is completing an Amendment dealing with calibration for asymmetries (P1588f).

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

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What are you testing?

Standard

Technical Overview

Test Guide

What are you testing?

Standard

Technical Overview

Test Guide

 

General

PTP Profile Compliance: The key to network timing interoperability

 

 

Time and Time Error, A Guide to Network Synchronisation

 

 

 

 

 

Frequency Network Limits

G.8261.1

 

 

Sentinel Field Test Plan for Frequency Synchronisation using PTP

SyncE Clock

 

G.8262

 

Jitter and Wander in SyncE: Testing Jitter and Wander to ITU-T Standards

G.8262 SyncE conformance testing: Proving SyncE compliance to ITU-T G.8262 using Paragon-X

  

The importance of measuring wander on high speed interfaces

Testing EECs to ITU-T G.8262 using Paragon-100G

Time and Phase Network Limits

G.8271.1

 

 

Sentinel Field Test Plan for TDD-LTTE/LTE-A Synchronisation using PTP

G.8271.2

 

 

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



Testing a T-BC to ITU-T G.8273.2

 T-BC Time Error: Testing Boundary Clocks to ITU-T G.8273.2 using Paragon-X

Measuring Time Error Transfer of G.8273.2 T-BCs

PTP Time Error for T-BC: Testing Boundary Clocks to ITU-T G.8273.2 using Paragon-100G

 

 

T-TSC Time Error: Testing Time Slave Clocks to ITU-T G.8273.2 using Paragon-X

Transparent Clock

G.8273.3

 

 

T-TC Time Error: Testing Transparent Clocks to ITU-T G.8273.3 using Paragon-X

Time-Aware Relay

IEEE802.1AS (gPTP)

gPTP: Proving Time Accuracy for Automotive Systems

 Time Aware Relay: Time Error Testing using Paragon-X

gPTP: Testing Synchronisation for Industrial TSN