ITU-T G.8271 (General) One-Page Summary
Title: Time and phase and synchronization aspects in packet networks
Summary
General aspects and concepts for time distribution
Requirement categories (based on external standards, e.g. 3GPP)
Defines timing interfaces (e.g. 1pps) and associated serial time-of-day messages
Status
Current version: 4.1 Edition, August 2024, Amendment 1 to 2020 Revision
Download from: http://www.itu.int/ITU-T/recommendations/rec.aspx?rec=13383
Key Contents
Accuracy Classes:
Level of Accuracy | Time error requirements | Typical applications |
|---|---|---|
1 | 500ms | Billing, alarms |
2 | 100µs | IP Delay monitoring |
3 | 5µs | LTE TDD (≥ 3km cell) |
4 | 1.5µs | UTRA-TDD, LTE-TDD, NR TDD Synchronous Dual Connectivity NR Carrier Aggregation |
5 | 1µs | WiMAX-TDD (some configurations) |
6 | <500ns | Various radio co-ordination techniques |
Network Reference Model:
Serial Time-of-Day Messages:
Message types:
Time event message
Time announce message
GNSS status message