Distributed control of telecommunication network for setting up an alternative communication path

Claim 1

A method for restoring a communication failure in a network, said network comprising a plurality of nodes (N2 - N8, N2' - N8') connected with each other by links (L0 - L5, L0' - L5'), each link including a plurality of paths for carrying a traffic of information, characterized by the steps of: providing a predetermined order for selecting the paths for each of said links included in said network; searching an alternative communication path upon a failure in communication occurring in said network; producing, at a first arbitrary node (N8, N8') included in said alternative communication path, a first path setup message containing at least information about the number of the paths to be selected in a link extending from said first node and forming said alternative communication path, for setting up said alternative communication path, and an identification code of the path that is to be first selected in a first link (L2, L2') that extends from said first node and forming a part of said alternative communication path; transmitting said first path setup message through said first link (L2, L2') to a second node (N4, N4') also included in said alternative communication path and located adjacent to said first node, said second node being connected to said first node by said first link; selecting, at said second node (N4, N4'), paths in a second link (L3, L3') that forms a part of said alternative communication path and exits from said second node at a side opposite to said first link, said step of selecting the paths in said second link being conducted to select a predetermined number of paths specified by said first path setup message according to said predetermined order of selection; effecting, at said second node (N4, N4'), a connection of said paths selected in said first link (L2, L2') to said paths selected in said second link (L3, L3'); producing a second path setup message at said second node such that said second path includes at least information about the number of the paths selected in said second link for setting up said alternative communication path and an identification code of the path that is first selected in said second link; and transmitting said second path setup massage from said second node along said second link to another node (N2, N2') included also in said alternative communication path and connected to said second node by said second link.

Claim 8

A method for restoring a communication failure in a network, said network comprising a plurality of nodes (N2 - N8) connected with each other by links (L0 - L5), each link including a plurality of paths, characterized in that said method comprises the steps of: providing a predetermined order of selection to each path in a link (L0 - L5); searching for an alternative communication path extending from a first end node (N8) to a second end node (N2) via an intermediate node by activating a path search process; deciding the transmission capacity necessary for said alternative communication path; effecting a connection, at said first end node (N8) and after said step of searching for said alternative communication path has been completed, between the paths (0003, 0002, 0004) included in a first link (L1) extending from said first end node (N8) and forming a part of an original communication path, and the paths (1001, 1002, 1003) included in a second link (L2) extending from said first end node and forming a part of said alternative communication path, said paths in said second link being determined based upon said transmission capacity of said alternative communication path; transmitting from said first end node (N8) a path setup message that contains information about the transmission capacity (200M) that is required for the alternative communication path, the number of the paths (3) included in said second link and used for said alternative communication path, and an identification of a reference path (1001) that is included in said second link and used for said alternative communication path, said path setup message being transmitted along said second link (L2), said reference path being the first path in said second link that is selected for said alternative communication path; identifying, in an intermediate node (N4) included in said alternative communication path and to which a path setup message is supplied via a third link (L2) that forms a part of said alternative communication path, the paths (1001, 1002, 1003) included in said third link (L2) and to be switched at said intermediate node (N4) for setting up said alternative communication path, based upon said path setup message supplied thereto, said path setup message containing information about the transmission capacity (200M) that is required for the alternative communication path, the number of the paths (3) included in said third link and to be used at said intermediate node for establishing said alternative communication path, and an identification of a reference path (1001) that is selected at first in said third link (L2) for establishing said alternative communication path; effecting a switching at said intermediate node (N4) for connecting those paths (1001, 1002, 1003) that are included in said third link and identified based upon said path setup message, to paths (2001, 2002, 2003) that are included in a fourth link (L3) that extends form said intermediate node (N4) and forming a part of said alternative communication path, said intermediate node further transmitting a modified path setup message via said fourth link (L3) such that said modified path setup message contains a reference path (2001) that is selected at first in said fifth link for said alternative communication path, in addition to the information indicative of the transmission capacity (200M) required for said alternative communication path and the number of the paths (3) used for the alternative communication path; identifying, in said second end node (N2) to which a path setup message is supplied via a fifth link (L3) that forms a part of said alternative communication path, the paths included in said fifth link (L3) and to be switched at said second end node for setting up said alternative communication path, based upon a path setup message supplied thereto, said path setup message containing information about the transmission capacity (200M) that is required for the alternative communication path, the number of the paths (3) included in said fifth link and to be used at said intermediate node for establishing said alternative communication path, and an identification of a reference virtual path (2001) that is included in said paths in said fourth link (L3) and is selected at first for establishing said alternative communication path; and effecting a switching at said second end node (N4) for connecting those paths (2002, 2001, 2003) that are included in said fifth link (L3) and identified based upon said path setup message, to paths (0002, 0003, 0004) that are included in a sixth link that extends form said second end node and forming a part of an original communication path.