Patent ID: 7551634

Claim:
A communication network system, comprising: plural lower hierarchy networks having plural first relay apparatuses that accommodate at least one terminal in a distributed arrangement, respectively, adjacent first relay apparatuses being connected by a line, respectively; an intermediate hierarchy network having plural second relay apparatuses, adjacent second relay apparatuses being connected by a line respectively, and connecting the plural lower hierarchy networks via the second relay apparatuses in edge positions to be connected with the first relay apparatuses in respective edge positions in the plural lower hierarchy networks by line; and an upper hierarchy network having, when a plurality of the intermediate hierarchy networks are present, plural third relay apparatuses, adjacent third relay apparatuses being connected by a line, and connecting the plural intermediate hierarchy networks via the third relay apparatuses in edge positions that are connected with the second relay apparatuses in the respective edge positions in the plural intermediate hierarchy networks by a line; wherein each of the first relay apparatuses in the plural lower hierarchy networks has a first routing table adopting a simple structure by holding routing information limited to routing information corresponding to own first relay apparatus, to routing information on the first relay apparatus coming into an adjacent state through the line and to routing information on the second relay apparatus in the edge position if coming into the adjacent state, first routing tables in the first relay apparatuses hold different routing information from each other; each of the second relay apparatuses in the intermediate hierarchy network has a second routing table that holds routing information on the second relay apparatus coming into an adjacent state through the line and routing information on the first relay apparatus in the edge position if coming into the adjacent state, second routing tables in the second relay apparatuses hold different routing information from each-other; the second routing table of each of the second relay apparatuses in the plural intermediate hierarchy networks further holds routing information for routing to the third relay apparatus in the edge position; and each of the third relay apparatuses in the edge positions in the upper hierarchy network has a third routing table to perform routing processing based on parameters for specifying a priority of a line in each section of the third relay apparatuses in an adjacent state that intervenes between two of the third relay apparatuses in the edge positions.