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LEI LIU ET AL.
© 2010 Taylor & Francis Group, LLC
Nox performs the wavelength assignment (WA). A new IA-R algo-
rithm, with the objective function code [41] 32770, is implemented in
the PCE for intra-/interdomain path computation. is algorithm,
which is developed based on Ref. [42], is able to compute a path with
minimum cost and satisfied OSNR inside each domain. e multi-
domain path computation is based on the backward recursive path
computation (BRPC) [49]. e destination domain PCE computes
a virtual shortest path tree (VSPT) from the domain ingress nodes
to the destination node and then sends the computed VSPT to the
upstream PCE to compute its own VSPT. e upstream PCE recur-
sively applies this procedure up to the source domain, obta ...