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---- |
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In real-world deployments, redundancy and recovery mechanisms are critical to maintaining accurate time synchronization if one of the time synchronization sources fails. |
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This test is designed to measure any changes in the time error at the output of each Telecom Boundary Clock when the primary Telecom Grandmaster (T-GM) fails, and a switch to the secondary T-GM occurs. |
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[[~[~[Figure 95: Time Synchronization Source Failover - Test bed setup of both test runs~>~>image:487681444567646209_SourceFailover.png~|~|alt="Figure 95"~]~]>>attach:487681444567646209_SourceFailover.png||target="_blank"]] |
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Two separate Microchip TimeProvider 4500 units were used as T-GM-A and T-GM-B, with all T-BCs being directly connected to both T-GMs. T-GM-A acted as the primary Grandmaster, as each Boundary Clock was configured with local priorities to prefer and lock to T-GM-A for both PTP and SyncE. |
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We disconnected the GNSS from T-GM-A, causing the BCs to switch to T-GM-B. After measuring for 1000s, including the failover, the measurement was restarted, and the GNSS connection to GM-A was reestablished, with all T-BCs locking back to T-GM-A on PTP and SyncE. The Calnex Paragon neo, Paragon neo-A, and the Keysight Time Sync Analyzer were used to measure the PTP and SyncE output of all the T-BCs. |
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We executed two separate test runs with different T-BCs but using the same procedure. |
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For both runs, the two-way time error for all devices was within the class-level accuracy limit of 6C (±65 ns), as per ITU-T G.8271, throughout the failover from T-GM-A to T-GM-B and the switchover back from T-GM-B to T-GM-A. For the MTIE, all devices were well within the threshold of the “Holdover Performance Const. Temp. T-BC/T-TSC Class A/B”, as specified in ITU-T G.8273.2, Table 7-10/Figure 7-1. |
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{{container cssClass="tc-role-table"}} |
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|=Telecom Grandmasters|=Telecom Boundary Clocks|=Frequency/Phase Analyzers |
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|Microchip Time Provider 4500 (T-GM-A), |
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Microchip Time Provider 4500 (T-GM-B)|HPE MX304, |
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Cisco 8011-4G24Y4H-I, |
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Ericsson RAN Connect 6682, |
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ZTE ZXCTN 6120H-S, |
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Ciena 5164, |
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Raisecom iTN8800-A, |
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HPE ACX7024, |
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Microchip Time Provider 4500, |
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ZTE ZXR10 M6000-4SE, |
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Ericsson Router 6676|Calnex Paragon neo, |
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Calnex Paragon neo-A, |
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Keysight Time Sync Analyzer |
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{{/container}} |
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Table 75: Time Synchronization Source Failover - Devices under Test |
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|[[< Previous>>doc:Assisted Partial Timing Support - Delay asymmetry detectionmeasurement and compensation]]|[[Next ~>>>doc:Time Error Accumulation and Calculation for Class D Telecom Boundary Clocks]] |
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{{include reference="Main.EANTC Transport & Cloud Networks Interop Test Report 2026.Sidebar Nav"/}} |
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