#PTP #InterDomain #MultiDomain

Every PTP message contains a domain number.  A PTP instance is configured to work in one, and only one, domain.  It is required to ignore messages with any other domain number.  The point of this complication is to allow different independent timing systems to inhabit the same network without confusing each other. For example, a management timing system and an experimental timing system.  The later might be used to test new PTP equipment. A device can have multiple PTP instances operating simultaneously, possibility operating in different domains.  However, from the point of view of PTP, they are different PTP instances. From a protocol point of view, domains are still independent in the upcoming revision, but we describe how multiple PTP domains can be used to accomplish certain goals in multi domain timing system.  One example is to transfer the time from one PTP domain to another.