r. The slave port can decide to request traffic for either one-way or two-way traffic from the re- mote master port based on its requirements. The master must be able to support both methods. For two-way operation, the Delay_Req and Delay_Resp messages are used, but the Pdelay mes- sage set is not used, SO there are no P2P TCs allowed in this profile. Quality (clockClass) values have specific values within the range of 6-255 (depending on the clock type). When operating normally, a value of 6 is expected across the network. Local priority can be configured on each PTP port of a clock to act as a tiebreaker in the case where multiple paths to a grandmaster are available. This is used where the operator wishes to define a preferred path. Packet timing signal fail (PTSF) whereby the timing messages from the master are either lost (PTSF-lossSync) or outside the input tolerance of the slave (PTSF-unusable). There is a new port dataset member (portDS.SF) that indicates that the port (if the value is TRUE) has suffered a signal failure and is no longer capable of being considered as a candidate port in the decision to select the best master. Fixes the value of priority1 at 128 but allows the value of priority2 to be configured in the range of 0-255 for T-GM, T-BC-P, and T-BC-A clocks (default of 128) and fixed at 255 in T-TSC-A and T-TSC-P clocks. The aBMCA selects a port receiving the higher priority2 (lower value) to be the slave to a grandmaster if the clock quality is otherwise equal. Appendix I of G.8275.2 de- scribes possible use cases for the priority2 attribute. G.8275.2 is deployed as PTPoIP over an Ethernet, IP, and MPLS network with the unaware nodes between the master and slave port simply switching the frames like any other. Of course, the net- work should be designed to minimize any impact that this unaware switching has on the delivered timing accuracy-more on that in Chapter 9. G.8275.2 is straightforward to configure and deploy, although in a large network, the manual provi- sioning of the addresses of 