SN2100 PTP sync Grandmaster

Infrastructure & Networking Switches and Gateways Ethernet Switches
1

I have two servers that I am trying to sync through the MSN2100 switch. I am doing the instructions in the manual as well as here:
https://mellanox.my.site.com/mellanoxcommunity/s/article/ieee-1588-ptp-on-spectrum-switches-running-onyx

I am able to sync to one PTP server, but am unable to sync to the other. I believe it is because of the “interface ethernet 1/# ip .” part. Both servers have a similar ip 192.168.1.XXX. I can only set one IP that will satisfy the IPs. When I try to set the other port’s IP, I get subnet overlap or already configured. If I set a separate IP, itll send the PTP to the port, but the server wont sync to it.

Both PTP servers are using linuxptp/ptp4l to sync to the switch.

Any help would be appreciated.

2

PTP can also be configured on a VLAN with trunks instead of layer-3 interfaces. You would need to configure the VLAN with an IP, configure the switchports as hybrid/trunk ports, add the VLAN to the truinks, enable PTP on the VLAN, and finally enable PTP on the interfaces.

3

So I started doing that, and it started working, but for some reason, the server connected to the grandmaster syncs to the switch instead of the grandmaster. The grandmaster and server (32 and 64 respectively) have a lower priority number than the PTP (128). Any idea why the ptp keeps getting selected as grandmaster? Assuming 'show ptp’s GMC identity field is the overall grandmaster

also, when i do “show ptp,” it shows that both ports are master. Shouldn’t one be master and one be slave?

4

Yes, the switchport attached to the GM clock should be master, and the other ports should be slave.

The PTP communication happens between each pair of devices, so on each side of each link, one will be master and one will be slave.

Yes, the GMC identity will be the address of the clock that time is originating from, not the neighboring clock.

A support case would be the best way to get help when deeper troubleshooting is required.

5

I dont have the GM clock directly connected to the switch due to constraints. With that, the server connected to the GM Clock/PTP time source should be the master while the switch and other server should be a slave but “show ptp” shows otherwise as both ports being master (thus one should be master and the other should be slave).

I am trying to understand why the GMC identity isn’t the GM Clock and is instead the clock identity in the switch

I followed the instructions for PTP switch interface here
https://docs.nvidia.com/networking/pages/viewpage.action?pageId=19807036

6

Update, it was a firewall issue on the server. Now the PTP server keeps toggling between grandmaster clock between itself and server 1. @chada1 is there any reason why? I tried using force-master as well as amt, but those seem to block the desired master instead.

I am hoping to get 00:21:32:FF:FE:01:B9:90 to be the master clock. It only identifies the server as GMC when its un-calibrated. I have the GMC have a lower clock class, accuracy, priority1 and 2, but it still isn’t syncing.

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