s profile over a PTS network where the elements are PTP unaware, and are merely switch- ing PTP messages as IP, does not allow the accuracy of the distributed time to be controlled. How- ever, the more PTP-aware elements that are included in the network, the better the performance will be. Additional considerations and details on PTS versus APTS are covered in the G.8271.2 recom- mendation on network topology. This recommendation specifies the characteristics and behavior of the following clock types from G.8275: Telecom Grandmaster (T-GM): A 1588-2008 grandmaster ordinary clock with a single mas- ter-only port. Telecom Grandmaster (T-GM): Another grandmaster with the same characteristics, but that has multiple (master only) ports. Because of 1588-2008 rules, any clock with more than one port is a boundary clock, SO according to that rule, this device is a 1588-2008 boundary clock acting just like a (ordinary clock) T-GM. Telecom Boundary Clock-Partial (T-BC-P): A boundary clock with partial support from the network. The difference between the T-BC-P and the multi-port T-GM is that the T-BC-P can be a slave to another clock, whereas a T-GM can never be. Telecom Boundary Clock-Assisted (T-BC-A): A boundary clock with only partial support from the network but assisted by a local time reference (such as a GNSS receiver) as a primary source of time. A slave port recovering clock over the PTS network is only used as a reference upon failure of the local time source. Clock feature and performance characteristics of the T- BC-A are covered in G.8273.4. Telecom Transparent Clock-Partial (T-TC-P): An E2E TC as defined in 1588-2008 with only partial support from the network. Telecom Time Slave Clock-Partial (T-TSC-P): An ordinary slave clock (and therefore only one PTP port) with partial support from the network. Telecom Time Slave Clock-Assisted (T-TSC-A): An ordinary slave clock with partial support from the network but assisted by a local time reference (such as a GNSS receiver) as a primary source of time. A slave port