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ChrisvT
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Precision Time Protocol over IPsec tunnel (PTP IEEE 1588)

Wed Apr 13, 2022 5:17 pm

Hi Folks,

I need some help figuring out the below.

I have some radio devices that use PTP and 2 x CRS328 switches that need to sync PTP with each other. I have added a very basic drawing for reference.
Schermafbeelding 2022-04-13 144938.png
The two CRS328 switches are in separate locations and I have configured PTP on them according to: https://help.mikrotik.com/docs/display/ ... e+Protocol
The CRS on the side of the MgmtServer should be the clock master(Grandmaster) and the other CRS located in a different city the slave.

The question is how can I get PTP to sync between the MikroTiks when they are not located on the same LAN?

Note I have tried adding an EoIP interface and adding it to the bridge on each switch but the slave does not sync.
The two switches can ping each other.
Running ROS 6.47.9

Thanks in advance.
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smyers119
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Re: Precision Time Protocol over IPsec tunnel (PTP IEEE 1588)

Wed May 04, 2022 7:09 am

ptp communicates using multicast. ptp is not meant to span across geographic locations. This is against best practice and you are not going to have good results.

"care must be taken when extending PTP. Varying latency across a WAN can compromise PTP accuracy as the PTP mean path delay is constantly changing it is recommended to use different PTP grandmasters in each site and not extend PTP across these sites"
 
ChrisvT
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Re: Precision Time Protocol over IPsec tunnel (PTP IEEE 1588)

Wed May 04, 2022 11:20 am

ptp communicates using multicast. ptp is not meant to span across geographic locations. This is against best practice and you are not going to have good results.

"care must be taken when extending PTP. Varying latency across a WAN can compromise PTP accuracy as the PTP mean path delay is constantly changing it is recommended to use different PTP grandmasters in each site and not extend PTP across these sites"
Hi smyers,

Thanks for your reply!
I found a usefull wiki link (https://en.wikipedia.org/wiki/Precision ... chitecture) that explains PTP in more detail.
Indeed our setup has changed and we have now placed the GM in the same location as the radios (although we haven't gotten PTP to work between the MikroTik and the radios yet).

Fingers crossed today is the day!

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