  Many network applications, e.g., industrial control, demand Ultra-Low Latency
(ULL). However, traditional packet networks can only reduce the end-to-end
latencies to the order of tens of milliseconds. The IEEE 802.1 Time Sensitive
Networking (TSN) standard and related research studies have sought to provide
link layer support for ULL networking, while the emerging IETF Deterministic
Networking (DetNet) standards seek to provide the complementary network layer
ULL support. This article provides an up-to-date comprehensive survey of the
IEEE TSN and IETF DetNet standards and the related research studies. The survey
of these standards and research studies is organized according to the main
categories of flow concept, flow synchronization, flow management, flow
control, and flow integrity. ULL networking mechanisms play a critical role in
the emerging fifth generation (5G) network access chain from wireless devices
via access, backhaul, and core networks. We survey the studies that
specifically target the support of ULL in 5G networks, with the main categories
of fronthaul, backhaul, and network management. Throughout, we identify the
pitfalls and limitations of the existing standards and research studies. This
survey can thus serve as a basis for the development of standards enhancements
and future ULL research studies that address the identified pitfalls and
limitations.
