  Deterministic Networking (DetNet) is a rising technology that offers
deterministic delay \& jitter and zero packet loss regardless of failures in
large IP networks. In order to support DetNet, we must be able to find a set of
low-cost routing paths for a given node pair subject to delay-range
constraints. Unfortunately, the \textbf{Delay-Range} Constrained Routing (DRCR)
problem is NP-Complete. Existing routing approaches either cannot support the
delay-range constraints, or incur extremely high computational complexity.
  We propose Pulse$+$, a highly scalable and efficient DRCR problem solver.
Pulse$+$ adopts a branch-and-bound methodology and optimizes its pruning
strategies for higher efficiency. We also integrate Pulse$+$ with a
divide-and-conquer approach and propose CoSE-Pulse$+$ to find a pair of
active/backup paths that meet DetNet's delay-range and delay-diff constraints.
Both Pulse$+$ and CoSE-Pulse$+$ offer optimality guarantee. Notably, although
Pulse$+$ and CoSE-Pulse$+$ do not have a polynomial worst-case time complexity,
their empirical performance is superior. We evaluate Pulse$+$ and CoSE-Pulse$+$
against the K-Shorst-Path and Lagrangian-dual based algorithms using synthetic
test cases generated over networks with thousands of nodes and links. Both
Pulse$+$ and CoSE-Pulse$+$ achieve significant speedup. To enable reproduction,
we open source our code and test cases at [1].
