Ethernet has been the backbone of IT infrastructure for over 40 years, but are you aware that more and more time-sensitive applications are moving into this environment? When it comes to industrial manufacturing, or communication in a vehicle, it is essential to implement real-time processes that can be properly executed by their respective components, to keep a factory floor, or vehicle, running smoothly and according to expectations.
It's About Time and Sync
Think about a robot-based production line in an automotive manufacturing plant. What if for every 10th vehicle, the production line needed to restart due to a timing drift? What if a time-sensitive task missed the exact window of opportunity, causing a robot to drop a part at the wrong time? What if one machine got tangled with another?
To avoid such critical errors, it is vital to complete processes precisely at the right time, as all the following steps depend on one another. Steps need to be conducted within a limited amount of time to get the production done properly, but they also need to be completed in a safe and secure manner. Time-critical processes effect manufacturing plants, gas and oil, energy, post and parcel distribution, and many other areas. When it comes to the vehicle of the future, where sensors and connectivity related to navigation, cameras or brakes are involved, time-sensitive networking is essential for road safety and vehicle security.
The demand for real-time communication in Automotive manufacturing is steadily growing as more and more sensors are being utilized in the design. The goal is to equip a single network with time-sensitive networking (TSN) enabled components that have reserved resources for time-critical data transmission, enabling communication inside and outside the vehicle – and in all future industrial environments.
The IEEE 802.1AS Generalized Precision Time Protocol (gPTP) allows all devices in a common network to have a common time reference, time synchronization and non-negotiable time boundaries for end-to-end transmission latencies. It is necessary to have synchronized clocks in the whole environment, which also includes switches, to execute and operate the required processes in the exact timeframe required.
Timing is Everything
To support a common time base in a network, having one single time source is the standard. This can be a GNSS or a Radio based clock. Even if the clock doesn’t always have access to an outside signal, the time distribution is still reliable, as it is based on the IEEE 802.1AS gPTP protocol. The TSN Task Group of the IEEE 802.1 Committee has specified multiple profiles to support the ever-changing timing requirements for TSN networks.
Spirent understands these timing needs and has generated multiple timing profiles, which can be used in our emulators to support simulating devices using any of these relevant protocols in use today: Best Clock Master Algorithm, 802.1AS-Rev, Automotive, Avnu and Industrial Profiles, to support the growing number of devices being built today. This will enable device vendors and vehicle manufacturers to easily test and validate their implementations, because they can define which profile to use during device checkout, Industrial Automation Networks or In-Car-Networks.
TSN Standards in Place Today
Standard bodies including the IEEE (Institute of Electrical and Electronics Engineering) are constantly improving the quality of Time-Sensitive Networking standards. The list below includes just some of the various TSN standards that Spirent is testing today:
IEEE 802.1AS-Rev - Enhanced Generic Precise Timing Protocol: Adds support for Performance, Redundancy, Aggregation
IEEE 802.1Qbv - Time Aware Shaper: Achieves the theoretical lowest possible latency in engineered networks
IEEE 802.1Qbu & IEEE 802.3br – Packet Pre-emption: Reduces latency of time-sensitive streams in non-engineered networks
IEEE 802.1CB - Frame Replication & Elimination: Supports zero switch over time when a link fails or frames are dropped (aka: Seamless Redundancy)
IEEE 802.1Qcc - Enhanced Stream Reservation Protocol: Adds support class configurations, shaper and replication
IEEE 802.1Qci - Per Stream Filtering & Policing: Assigns flows to policer
IEEE 802.1Qch - Cyclic Queuing & Forwarding: Supports known latencies, no central controller needed, limits hops
IEEE 802.1Qcr - Asynchronous Traffic Shaping: Supports zero congestion loss for asynchronous traffic, and deterministic latency without using network topology information
Spirent, a market leader in communication testing, supports and participates in different setups for TSN + OPC UA Smart Manufacturing testbeds, and works with Standard Consortiums like SCI and the LNI 4.0 for Industrial Networks. TSN + OPC UA helps industrial companies improve overall device efficiency, enhance efficiency by reducing downtime, along with reducing total cost of ownership.
Recently, several pioneers including Spirent, helped a major market leader in IT and Industrial Infrastructure, establish a. The testbed simulated real-life smart manufacturing conditions to help companies enhance efficiency. Spirent test devices were used to generate TSN and non-TSN traffic to prove the benefits brought by new industrial network architecture and services.