Futurewei Technologies USA Stewart Bryant Ltd The purpose of this memo is to explain the challenges and limitations of existing (standardized) bounded latency queuing mechanisms for desirable (large scale) MPLS and/or IP based networks to allow them to support DetNet services. These challenges relate to low-cost, high-speed hardware implementations, desirable network design approaches, system complexity, reliability, scalability, cost of signaling, performance and jitter experience for the DetNet applications. Many of these problems are rooted in the use of per- hop, per-flow (DetNet) forwarding and queuing state, but highly accurate network wide time synchronization can be another challenge for some networks. This memo does not intend to propose a specific queuing solution, but in the same way in which it describes the challenges of mechanisms, it reviews how those problem are addressed by currently proposed new queuing mechanisms.