Patent ID: 7333424
Filing Date: 2008-02-19
Classification: H04J,H04Q

Abstract:
1. An upper layer node which is used in a multi-layer network which comprises an upper layer network which performs switching and transfer in units of packets, and a lower layer network which accommodates the upper layer network and which comprises optical transmission fines and optical switches; the upper layer node being connected to the lower layer network which comprises a plurality of lower layer nodes which comprise obstruction restoration sections, and transmission lines; and the upper layer node comprising: a detection section which detects the occurrence of an obstruction upon a transmission line which the upper layer node accommodates; an advertisement section which advertises the result of detection by the detection section as obstruction information; a section which retains the topology information for the lower layer network; an updating section which updates the topology information which the upper layer node retains, according to obstruction information which has been advertised, or obstruction information which the upper layer node has detected; and an advertisement transfer section which advertises to other upper layer nodes obstruction information which has been advertised, wherein the updating section comprises a deferral section which defers the updating of the topology information for a time period T from the time instant that the detection section has detected the occurrence of an obstruction.