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Global Navigation Satellite System (GNSS) capability is essential for the Grand Master (GM) clock functionality. A GNSS receiver receives signals from a navigation satellite constellation. The GNSS receiver gains precise phase and time information by processing these signals and delivers the information across the network.

Starting in Junos OS Evolved Release 23.1R1, the ACX7024 supports telecom grandmaster (T-GM) functionality using an external GNSS receiver as a source for time information. The GNSS receiver obtains and processes the signals from a navigation satellite constellation to deliver precise phase and time information across the entire packet network. The T-GM functionality can be used, for example, to provide required synchronization to base stations in a data network. With this feature, the ACX7024 devices can function as an edge T-GM by connecting to an external Furuno TB-1 GNSS receiver.

The Furuno TB-1 GNSS receiver supports the following timing standards:

The Furuno TB-1 GNSS receiver and the Telecom Grand Master (T-GM) functionality on the ACX7024 device provides several benefits including the following:

  • Multi-constellation receiver that supports:

    • GPS L1C/A



    • QZSS L1C/A

  • Time traceability to GPS or UTC

  • Coherent 10-MHz and 1- pulse per second (PPS) outputs

  • OCXO-based receiver

  • Anti-jamming and anti-spoofing support that includes multipath spoofing, jamming, interference detection and isolation mechanisms.

  • Supported on 10G and 25G ports.
  • Transmission of Ethernet Synchronization Message Channel (ESMC) and enhanced ESMC packets for synchronous Ethernet as per G.8264 standards.

For more information about the Furuno TB-1 GNSS receiver, see the TB-1 Operation Manual.