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ITU-T G.8271.2 (Network Limits - PTS) One-Page Summary

ITU-T G.8271.2 (Network Limits - PTS) One-Page Summary

Sept 10, 2025

Title: Network limits for time synchronisation in packet networks with partial timing support from the network

Summary

  • Defines the reference model for packet synchronization network assuming partial timing support

  • Defines network limits at each reference point

  • Describes different potential deployment scenarios for the network

Status

Key Contents

Network Reference Model:

With GNSS assistance (APTS):

Without GNSS assistance (APTS):

Network Limits:

Reference points A and B:

  • Max|TE| < 100ns

Reference point C, APTS:

  • Peak-to-peak pktSelected2WayTE < 1100ns

  • Selection window: 200s

  • Selection percentage: fastest 0.25%

Reference point C, PTS:

  • Maximum |pktSelected2WayTE| < 1100ns

  • Selection window: 200s

  • Selection percentage: fastest 0.25%

Reference point D, APTS and PTS:

  • Max|TE| < 1350ns

Example Deployment Scenarios:

GNSS backup using PTP (APTS):

Bridging between two full timing support networks:

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