ACX7024 Device GNSS Configuration

SUMMARY

The ACX7024 device supports the G.8275.1 profile, Telecom Grand Master (T-GM) time management functionality for all devices on the network on 10G and 25G ports. Additionally, the system supports the following functionalities:

– Compliance to ITU-T G.8272 (Unified functional architecture for transport networks) PRTC Class A.

– Support for multiple constellations such as GPS, GLONAS, QZSS and Galileo.

– Support for multipath spoofing, jamming, interference detection and isolation mechanisms.

Use the following commands to configure the T-GM functionality:

– set chassis synchronization gnss-receiver <(0|1)> receiver-type <name>

– set chassis synchronization gnss-receiver <(0|1)> interface

Use the following commands to enable GM functionality:

– set protocols ptp clock-mode ordinary

– set protocols ptp profile-type g.8275.1

– set protocols ptp master interface <interface-name> multicast-mode transport ieee-802.3

– ptp-mode

– gnss-receiver

– show chassis synchronization gnss-receiver extensive

– show chassis synchronization extensive

– show ptp lock-status detail

In T-GM mode router functions as an ordinary clock and all PTP configured ports are in "Master only" state. Up to 512 master ports are supported on ACX7024.

Note:

A synchronous Ethernet (SyncE) input is not allowed when system is functioning as a T-GM. Use the following command to configure a wait-to-restore check for SyncE input:

set chassis synchronization source interfaces et-0/0/4 quality-level prc wait-to-restore 0

Configure GNSS Receiver

The Furuno TB-1 GNSS receiver is designed to operate with multiple constellations. When connected to an external GNSS antenna, the receiver contains all the circuitry necessary to automatically acquire GNSS satellite signals, track GNSS satellites, and acquire precise position and timing solutions. It provides 1 pulse-per-second (PPS) precision timing and stable 10-MHz frequency output.

To optimize the GNSS capability, establish a common time scale and coordinated system between all the systems. This coordinated system simplifies network synchronization, provides flexibility and resiliency.

Table 1 describes the steps to configure GNSS receiver on ACX7024 router.

Table 1: GNSS Receiver Configuration
Configuration Step	Command
Step 1: (Mandatory) Enable GNSS receiver and grandmaster clock functionality. Enable the GNSS receiver by using the `gnss-receiver 0 interface` statement at the `edit chassis synchronization` hierarchy level. By enabling the GNSS receiver, you establish communication between the ACX7024 router and the GNSS receiver. Configure the satellite constellation by using the `gnss-receiver 0 constellation` statement at the `edit chassis synchronization` hierarchy level. Various constellations are available. Through this configuration, you can configure the GNSS receiver to explicitly use a specific constellation or combination of constellations. For more information, see clock-mode, profile-type, transport-ieee-802.3, gnss-receiver, and ptp-mode.	1. Set clock mode. [edit protocols ptp] user@host# `set clock-mode ordinary` 2. Set G.8275.1 profile type. [edit protocols ptp] user@host# `set profile-type g.8275.1` 3. Set transport protocol as IEEE 802.3. [edit protocols ptp master interface `interface name` multicast-mode] user@host# `set transport ieee-802.3` 4. Set the GNSS receiver interface. [edit chassis synchronization gnss-receiver `number`] user@host# `set interface` 5. Configure the GNSS receiver type as TB-1. [edit chassis synchronization gnss-receiver `number`] user@host# `set receiver-type tb-1` 6. Set the GNSS receiver constellation. [edit chassis synchronization gnss-receiver `number`] user@host# `set constellation` 7.Set PTP mode for FPC and PIC. [edit chassis fpc 0 pic 0] user@host# `set ptp-mode`
Step 2: (Optional) Specify the position mode. TB-1 as timing receiver has two different position modes— position-fix-mode and survey-mode. The default position mode is survey-mode if no specific mode is configured. position-fix-mode: Use this mode when you know the accurate antenna location. survey-mode: Use this mode when you do not know the fixed location of the antenna. For more information about position mode, see gnss-receiver.	[edit chassis synchronization gnss-receiver `number`] user@host# `set position-mode`
Step 3: (Optional) Specify the cable delay compensation value. This configuration is used to compensate the delay introduced due to RF cable which is routed from Antenna to TB-1 RF input. You can also use this command to compensate the PPS cable delay by adding both RF cable and PPS cable delays. For long cable runs, this delay can be significant. The range is from -1000000 to 1000000 nanoseconds. For more information about cable delay compensation, see gnss-receiver.	[edit chassis synchronization gnss-receiver `number`] user@host# `set cable-delay-compensation value`
Step 4: (Optional) Specify the Signal-to-Noise Ratio (SNR) threshold value. The SNR is the ratio of the signal power to the noise power. GNSS receiver measures SNR value to indicate the signal strength of the received satellite signal and the noise density. You can configure the SNR threshold value. Satellites with the signal level equal to or above the threshold value can only be used for positioning. range: 0 - 99 dBHz For more information about SNR threshold, see gnss-receiver.	[edit chassis synchronization gnss-receiver `number`] user@host# `set snr-threshold value`
Step 5: Commit the configuration.	[edit] user@host# `commit`
Step 6: Verify the configuration. For more information about the operational commands, see show chassis synchronization gnss-receiver extensive, show chassis synchronization extensive, and show ptp lock-status detail.	[edit] user@host# `run show chassis synchronization gnss-receiver extensive` [edit] user@host# `run show chassis synchronization extensive` [edit] user@host# `run show ptp lock-status detail` [edit] user@host# `run show ptp clock detail`