Re: [Linuxptp-devel] [PATCH v1 5/5] Implement the COMMON_P2P delay mechanism.

[Kishen M. <kis...@in...>]

On 12/1/23 10:07 PM, Richard Cochran wrote:
> On Thu, Nov 30, 2023 at 04:52:44PM -0800, Kishen Maloor wrote:
> 
>> CMLDS ptp4l process would be configured with
>> transportSpecific/domain=0x2/0.
> 
> Question about the spec:
> 
> How on earth is this going to work?
> 
> I mean, if the link partner is not also using CMLDS, then it won't
> reply because of the majorSdoId mismatch.

Yes, as we understand, that is indeed the case. IEEE 
1588-2019/16.6.3.1/Note 3 emphasizes this point and 16.6.3.2 specifies 
the wire protocol variations for CMLDS. So yeah, the link partner is
expected to run an instance of the service and they would interoperate.

> 
> Does the standard require that either ALL the nodes in a network use
> CMLDS, or none do at all?
> 

When the time-aware system supports multiple domains, IEEE 
802.1as-2020/11.2.17 mandates CMLDS and the COMMON_P2P DM.

Thanks,
-Kishen.