 and introduces an informative Annex P on security. See the earlier section "PTP Security" for more details on changes to the security mechanisms. Profile isolation: New (optional) section (16.5) on the isolation of PTP Instances running under profiles conceived by different SDOs when they are both running over the same network. Pro- file isolation in 2008 was very rudimentary (mainly relying on domain number) but is now ex- panded to include a PTP header field sdoId (repurposed from the transportSpecific field). The sdoId is an organizational ID value that an SDO can obtain from the IEEE Registration Author- ity. By requiring the use of this value in their profiles, SDOs can isolate messages belonging to their profiles from those of other SDOs. See section 16.5, "Isolation of PTP Instances running under profiles specified by different standards organizations." Slave event monitoring: This (optional) feature allows for monitoring timing information from a PTP port in slave state. Some networks have deployed various application-specific methods that allow a similar capability. However, this feature defines an application-independent mech- anism. It includes the definition of three new TLVs to carry information away from the slave. SLAVE_RX_SYNC_COMPUTED_DATA one of these TLVs, allows the sharing of computed fields like the offsetFromMaster and meanPathDelay. Additional datasets to support this feature are also defined. This simplifies the implementation and deployment of monitoring timing in- formation from the slave. See section 16.11, "Slave Event Monitoring," for details. Performance monitoring options: Annex J introduces another (optional) mechanism to report metrics from the PTP instances running on the node. It defines new datasets, including the per- formance monitoring dataset (performanceMonitoringDS) and performance monitoring port dataset (performanceMonitoringPortDS). This allows management access to statistics and metrics from the PTP instance. including clock and port parameters. See Annex J, "Perfor