Time sensitive Networking. This is the name of the IEEE 802.1 Task Group responsible for standards at Data Link Layer. This group provides the specifications that will allow time-synchronized, low latency, streaming services through IEEE 802 networks.
TSN is unique in that its streams are delivered with guaranteed bandwidth and deterministic latency. There are many features involved in the multiple standards currently under development. Some of the most relevant features and associated standards are:
- Synchronization: The synchronization is based on IEEE 1588-2008 protocol. A specific profile is defined at IEEE 802.1AS.
- Preemption: The concept of preemption is supported in TSN. A higher priority frame can interrupt the lower priority frame transmission to reduce the latency of time-sensitive streams (IEEE 802.1Qbu & IEEE 802.3br).
- Traffic shaper: to achieve the theoretically lowest possible latency in engineered networks, the Time-Aware Shaper functionality is introduced in TSN. This works with applications where time-critical data is sent on regular periodic intervals and it is based on adding time gates on each queue on a port.
- Redundancy: the high availability in TSN can be achieved by adding frame replication and elimination as defined in IEEE 802.1CB. Similarly as defined for HSR, the frames include a sequence number and they are replicated. Each copy is sent through a different path in the network.
- TSN is evolving and it is targeting different sectors, like Automotive, Industry, Broadcasting and Aerospace. This flexibility can be achieved through reconfigurable logic (FPGAs), HDL IPs and embedded software.