Case13: T5000 G8275.1 PTP Clock syn failure due to “managment message”

Country/Region: G

Equipment: ncell-T5000

Version: V3.6

1. Issue Description: ITU-TG8275.1 PTP clock synchronize failed.

2. Achieve Network Topology and NE Information

GrandMaster                             -> BC#1                             -> BC#2                             -> BBU

ClockIdentity:                     Clock Indentity:                     Clock Indentity:                    Clock Identity:

0x84c807fffe1d4358         0x649d99fffeb80040         0x649d99fffeb83c50          0x003064fffe6b2846

3. Suggested Troubleshooting Methods:

3.1 Compare ptp configurations

3.2 Check logs

3.3 Capture packets

4. Troubleshooting Procedures:

4.1 Align configurations with ptp server.

Align the eNodeB ptp syn protocol G82.75.1 profile and ptp server setting.

☯ Upload ptp4l-slave.cfg to /root

☯In the directory /opt/bbu/bts/scripts/, backup the current get1588Info.sh, and upload the new get1588Info.sh (attached) in here

☯The configuration in PTP server as below picture:

Adjust the parameter as per below:

☯enable PTP manually with the command: ptp4l -i enp184s0f0 -m -H -s -2 -f ptp4l-slave.cfg

4.2 Capture packets

We can see an extract of the compatibility problem in the summary table below:

The BC#2 sends 8 sync message within a second: OK

The BC#2 sends 1 Announce message: OK

Followed by another set of 8 sync packet within a second: OK

The BC#2 sends 1 Announce message: OK

The BBU sends Delay Request message and the BC#2 responds with the Delay Response: OK

The BC#2 sends the first Sync message for the following seconds.

The BBU send a PTP Management message GET.

The BC#2 is not able to cope with that PTP Management message which may belong to the 1588 Profile but not to the G.8275.1 profile.

The BC#2 is not able to provide neither Sync nor Delay Response messages till the BBU stops during at least 3 seconds sending the PTP management messages.

At this point we come back to point 1 and the cycle repeat itself forever.

Customer Border clock source, according to 3GPP.

G.8275.1 not support “management” message.

5. Solution: Modify the configuration of file /opt/bbu/bts/scripts/get1588Info.sh. Add “-b 0” after “-d 24” at place which invoke pmc.

As below:

After modify and reboot.

Clock locked. Check the result in web GUI: 

check the result in system:

a: /opt/bbu/oam/log, tail -f get1588Info

b: login accelerator card, the result should be as below picture:

ssh root@192.168.2.24

sjnt1234

Troubleshooting Methods: Download