ÙDecision Stage
ØConsider the network graph G(N,E) with nodes N, n=|N|, and the set E of directional links (i,j), where i,j Є N.
ØThe CPN algorithm explores G(N,E) and collects QoS data about the parts of the network that are
being currently used, or which have been explored by SPs. This data
is available in one or more locations in the form of nxn link QoS matrices Qv with
elements:
vQv(i,j)=r where r≥0 is a real number
representing the QoS of link (i,j) which has been measured at some recent enough time, and
vQv(i,j)=unknown if a SP has not explored
the link for QoS metric v or if this happened so long ago that the value could be
inaccurate.
ØFrom the link matrices Qv we can compute:
vThe set of known (explored) paths P(i,j) from i to j, and
vThe path QoS matrices Kv, where Kv(i,j) is the known best value of the QoS metric v for any path going from i to j if such a path exists and
if the links on the path have known entries in the link QoS matrices.
Other entries in Kv are set to the value unknown.