YateUCN as Network Time Server for Radio Equipment

LTE networks require accurate, secure, and reliable time services. We will use YateUCN linux server as a network time server with purpose to deliver exact hardware-based Network Time Protocol (NTP) timestamps to eNodeB equipment.

To enable hardware stamping, it needs to be supported by:

  • network interface card (NIC)
  • kernel
  • chrony (client/server for the Network Time Protocol)

To verify if NIC and kernel supports it, apply the command: ethtool -T interface_name

[root@yatebts_core ~]# ethtool -T enp1s0f1
Flag Meaning
SOF_TIMESTAMPING_TX_SOFTWARETransmit timestamp generated in kernel driver by NIC clock
SOF_TIMESTAMPING_RX_SOFTWAREReceive timestamp generated in kernel driver by NIC clock
SOF_TIMESTAMPING_TX_HARDWARETransmit timestamp generated in hardware by NIC clock
SOF_TIMESTAMPING_RX_HARDWAREReceive timestamp generated in hardware by NIC clock

chrony supports hardware stamping starting from Version 3.0 , chrony3.4-2 is build for Mageia 7.

  • We backported it to mga5 and mga6 and you can find it in the RAN repo of your delivered RAN equipment (LabKit or SatSite).
[root@yatebts_core ~]# urpmi.addmedia --update YateRAN https://repo.yatebts.com/unstable/mga5/x86_64

[root@yatebts_core ~]# urpmi.addmedia --update YateRAN https://repo.yatebts.com/unstable/mga6/x86_64

You can install it with:

urpmi.update Yate;urpmi chrony

You can verify the installed package (version) with command:

rpm -qa chrony

eNodeB equipment settings (SatSite or LTE LabKit)

  • Verify if chrony is the right version:
rpm -qa chrony
  • If yes, edit file: /etc/chrony.conf and comment line: "pool pool.ntp.org iburst" (add a # sign in front)
    * Add line: "server IP_of_UCN_server"
    * In the example below there are 2 UCN servers both as NTP servers for Radio Equipment.
[root@ybts-SatSite ~]# head -n 5 /etc/chrony.conf
# Use public servers from the pool.ntp.org project.
# Please consider joining the pool (http://www.pool.ntp.org/join.html).
#pool pool.ntp.org iburst
server 10.0.4.1
server 192.10.2.1
[root@ybts-SatSite ~]#
  • If no, install chrony and then edit the file
    * Restart chrony service (systemctl restart chrony)
    * To see logs (you need to enable them, last line of the chrony.conf file)
# Select which information is logged.
#log measurements statistics tracking
[root@ybts-SatSite ~]# head -n 5 /var/log/chrony/tracking.log
==================================================================================================
Date (UTC) Time IP Address St Freq ppm Skew ppm Offset L Co Offset sd Rem. corr.
==================================================================================================
2019-09-15 19:48:39 10.0.4.1 4 -7.077 0.059 -2.556e-06 N 1 2.706e-06 8.082e-07
2019-09-15 19:49:43 10.0.4.1 4 -7.084 0.053 -2.748e-06 N 1 2.930e-06 5.843e-07
[root@ybts-SatSite ~] #

References: