AVB/TSN can handle rate-constrained traffic, where each stream has a bandwidth limit defined by minimum inter-frame intervals and maximal frame size, and time-trigger traffic with an exact accurate time to be sent. Low-priority traffic is passed on best-effort base, with no timing and delivery guarantees. In contrast to standard Ethernet according to IEEE 802.3 and Ethernet bridging according to IEEE 802.1Q, time is very important in TSN networks. For real-time communication with hard, non-negotiable time boundaries for end-to-end transmission latencies, all devices in this network need to have a common time reference and therefore, need to synchronize their clocks among each other. This is not only true for the end devices of a communication stream, such as an industrial controller and a manufacturing robot, but also true for network components, such as Ethernet switches. Only through synchronized clocks, it is possible for all network devices to operate in unison and execute the required operation at exactly the required point in time. Although time synchronization in TSN networks can be achieved with GPS clock, this is costly and there is no guarantee that the endpoint device has access to the radio or satellite signal at all times. Due to these constraints, time in TSN networks is usually distributed from one central time source directly through the network itself using the IEEE 1588 Precision Time Protocol, which utilizes Ethernet frames to distribute time synchronization information. IEEE 802.1AS is a tightly constrained subset of IEEE 1588 with sub-microsecond precision and extensions to support synchronisation over WiFi radio (IEEE 802.11). The idea behind this profile is to narrow the huge list of different IEEE 1588 options down to a manageable few critical options that are applicable to Home networks or networks in automotive car or industrial automation environments. IEEE 802.1AS-2011 defines the Generic Precision Time Protocol (gPTP) profile which employs UDP messages to establish a hierarchy of clocks and synchronize time in a gPTP domain formed by devices exchanging time events. To account for data path delays, the gPTP prococol measures the frame residence time within each bridge (a time required for processing, queuing and transmission from ingress to egress ports), and the link latency of each hop (a propagation delay between two adjacent bridges). The calculated delays are then referenced to the GrandMaster (GM) clock in a bridge elected by the Best Master Clock Algorithm, a clock spanning tree protocol to which all from Clock Master (CM) and endpoint devices have to synchronize.