Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Light-Hierarchy: The Optimal Structure for Multicast Routing in WDM Mesh
  Networks   Based on the false assumption that multicast incapable (MI) nodes could not
be traversed twice on the same wavelength, the light-tree structure was always
thought to be optimal for multicast routing in sparse splitting Wavelength
Division Multiplexing (WDM) networks. In fact, for establishing a multicast
session, an MI node could be crosswise visited more than once to switch a light
signal towards several destinations with only one wavelength through different
input and output pairs. This is called Cross Pair Switching (CPS). Thus, a new
multicast routing structure light-hierarchy is proposed for all-optical
multicast routing, which permits the cycles introduced by the CPS capability of
MI nodes. We proved that the optimal structure for minimizing the cost of
multicast routing is a set of light-hierarchies rather than the light-trees in
sparse splitting WDM networks. Integer linear programming (ILP) formulations
are developed to search the optimal light-hierarchies. Numerical results
verified that the light-hierarchy structure could save more cost than the
light-tree structure.

31
The categories of this paper are: ao-sci
37
The categories of this paper are: supr-con
11
The categories of this paper are: hep-lat
36
The categories of this paper are: cmp-lg
32
The categories of this paper are: atom-ph
35
The categories of this paper are: mtrl-th
28
The categories of this paper are: alg-geom
5
The categories of this paper are: gr-qc
33
The categories of this paper are: plasm-ph
20
The categories of this paper are: acc-phys
29
The categories of this paper are: funct-an
27
The categories of this paper are: comp-gas
18
The categories of this paper are: econ
34
The categories of this paper are: chem-ph
4
The categories of this paper are: cond-mat
17
The categories of this paper are: q-fin