 and Synchronization for Time-Sensitive Applications in Bridged Local Area Networks." This specification facilitates the implementation of accurate time synchronization based on 1588/PTP and is commonly referred as generalized PTP or gPTP. The latest version of the profile is IEEE 802.1AS-2020. IEEE 802.1 IAS specifies a PTP profile using layer 2 to transport synchronized time over physical or virtual bridged LANs. It also allows synchronization over other media types such as Wi-Fi (IEEE 802.11). Chapter 7 discusses IEEE 802. 1AS in more detail along with the other important PTP profiles. The 802.1AS profile is one of the several key 802.1 standards that were designed for networked low-latency applications, most specifically audio-video (remember that the TSN group started out as AVB). As mentioned previously, they are brought together in the TSN profile (not a PTP profile) of IEEE Std 802. .1BA-2011. So, a TSN profile includes a PTP profile. Of course, this book is dedicated mainly to mobile applications, which (at least SO far) have made almost no use of the IEEE 802.1 PTP profile-therefore, it is of limited further interest. But it is worth looking at several TSN technologies that can be used in one of the TSN profiles or even as a standalone technology (see the TSN TG website, https://1.ieee802.org/tsn/ for much more details on these standards). TSN improves the real-time performance of time-sensitive network applications by adding two techniques: frame scheduling (IEEE 802.1Qbv) and frame preemption (IEEE 802.1Qbu). Frame scheduling is a technique that periodically allocates transmission time to different classes of traffic. The scheduler allocates each class of traffic a time slot during which it is allowed exclusive use of the Ethernet network, ensuring that the priority traffic can be granted guaranteed and uninterrupted transmission. This makes the path through the network much more predictable and deterministic. Frame preemption defines a mechanism to allow time-critical messages to interrupt ongoing tr