nt temperature and 63- 173 ns MTIE after 1000 S with the variable temperature. Of course, holdover tests should only be initiated following a period that allows the clock to settle down following setup. For accurate long-term tests, that should be up to 24 hours. Of all these tests, the most popular performance feature to test is the noise generation, with the cTE being the metric most operators are interested in. Table 12-2 outlines the parameters that define which class of clock the T-BC/T-TSC fits into, based on the noise generation results. Table 12-2 G.8273.2 Timing Classifications for Class of Boundary/Slave Clock Parameter Conditions Class A Class B Class C Class D Unfiltered TE for 1000 S 100 ns 70 ns 30 ns Unspecified max TEL 0.1-Hz LPF for 1000 S 1000 S averaged 50 ns 20 ns 10 ns Unspecified 0.1-Hz LPF, 1000 S constant temperature 40 ns 40 ns 10 ns dTEL MTIE Unspecified 0.1-Hz LPF, 1000 S variable temp 40 ns 40 ns Unspecified Unspecified dTEL TDEV 0.1-Hz LPF, 1000 S constant temperature Unspecified Peak-to-peak, 1000 S constant temperature 70 ns 70 ns Unspecified Unspecified Some additional tests that operators like to perform include testing the behavior of the clockClass variable, to confirm that the values being transmitted in the Announce message accurately reflect the state of the T-BC. Also popular is checking the PTP 2wayTE measurement during an event like a switchover in the control plane processors or a rearrangement in the network that changes the pre- ferred GM. This section covered the case for clocks supporting the FTS in G.8273.2, SO the next section looks at the PTS cases and the partial and assisted-partial versions of the T-BC and T-TSC clocks. Testing T-BC-A and T-TSC-A to G.8273.4 In the preceding section, G.8273.2 covered the cases of the PTP-aware clock with full on-path sup- port. This section, based on G.8273.4, covers the cases where there is only partial PTP support from the network, but a local time source is present to assist the clock. These test cases confirm the per- forman