On the Synchronous Ethernet for a Massive Networking Deployment: Insight Into a Tailored Cosimulated Testbed

Digital communications have a minimum synchronization requirement: the end user of a telecommunication system has to lock into the right bit rhythm sent by the other connection partner. Nevertheless, synchronization in the telecommunication context turns out to be broader than two connection partners locally linked: the suitable feed of a standard time, within many telecommunication domains, has vital importance for many applications to properly handle the demanded network functionalities. The time feed in multidomain scenarios makes a time path, which becomes a nested built-in network. Generally, the data distribution follows the time path in many telecommunication systems. However, the data path may not follow the time path for all scenarios and could partially follow some network branches, usually at the network border. To ensure efficient and controllable synchronization, we focus on the study of time paths. This article provides a first insight into a tailored cosimulated testbed, implemented to determine the time path behavior in terms of jitter and to supervise the drift from the primary reference clock (PRC) with more than 20 cascaded nodes, the maximum achievable cascaded depth within the current G.8262 standard. This cascading must meet the requirements of the International Telecommunication Union (ITU-T) standards G.8262/G.8261 in terms of long-term jitter (wander) and short-term jitter (jitter) to ensure a tolerable drift compared with the central clock. In particular, for Synchronous Ethernet (SyncE), the standard does not provide possible limits for the jitter beyond 20 synchronized nodes. The numerical results, with the extended number of nodes, show that this scenario remains feasible, the parameters being below the masks proposed by the standards.