Methods and systems for fast restoration in a mesh network of optical cross connects
First Claim
1. A method that restores communication in a mesh network between a first end node and a second end node, comprising:
- transmitting a communication signal over a first communication path comprising the first end node, the second end node and one or more first intermediate nodes;
detecting an error condition at at least one of the first end node and the second end node, said error condition being not adjacent to said at least one end node; and
said at least one end node initiating rerouting the communication signal over a second communication path based on the detected error condition in order to restore communication, the second path having been chosen before the error condition was detected, to carry the rerouted communication sisal and the second path including the first end node, the second end node, and one or more second intermediate nodes, wherein the second intermediate nodes are disjoint from the one or more first intermediate nodes;
the second path further including one or more transmission lines each having a plurality of channels, at least one said channel being assigned, after the error condition is detected, to carry the communication signal.
1 Assignment
0 Petitions
Accused Products
Abstract
The present invention provides methods and systems for restoring communication in a fiber optic network by placing error detection circuitry at the add/drop ports of the network nodes of the network. If the error detection circuitry detects an error condition for a communication signal traversing a normal communication path within the network, the communication signal is rerouted along a restoration communication path that is node and span disjoint from the first communication path. By requiring a restoration path to be node and span disjoint from the normal communication path, error detection circuitry need only be placed at the end nodes of the normal communication path. By allowing each node in the restoration path to dynamically choose the particular channels that can accommodate a particular communication signal at the time of the restoration, efficient use of available resources is gained. The result is a cost effective network that restores communication in times competitive to that of SONET rings.
49 Citations
41 Claims
-
1. A method that restores communication in a mesh network between a first end node and a second end node, comprising:
-
transmitting a communication signal over a first communication path comprising the first end node, the second end node and one or more first intermediate nodes; detecting an error condition at at least one of the first end node and the second end node, said error condition being not adjacent to said at least one end node; and said at least one end node initiating rerouting the communication signal over a second communication path based on the detected error condition in order to restore communication, the second path having been chosen before the error condition was detected, to carry the rerouted communication sisal and the second path including the first end node, the second end node, and one or more second intermediate nodes, wherein the second intermediate nodes are disjoint from the one or more first intermediate nodes; the second path further including one or more transmission lines each having a plurality of channels, at least one said channel being assigned, after the error condition is detected, to carry the communication signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
-
-
11. A mesh network having a first end node and a second end node, comprising:
-
a first communication path that transmits a communication signal, the first communication path including the first end node, the second end node and one or more first intermediate nodes; an error detecting device in at least one of the first end node and the second end node for detecting the occurrence of an error in any portion of said first communication path; and a predetermined second communication path that is chosen, before the error detecting device detects an error condition, to transmit the communication signal in the event that the error detecting device detects an error condition, the predetermined second path comprising the first end node, the second end node, and one or more second intermediate nodes, wherein the second intermediate nodes are disjoint from the one or more first intermediate nodes; the second path further including one or more transmission lines each having a plurality of channels, and at least one said channel being assigned, after the error condition is detected, to carry the communication signal. - View Dependent Claims (12, 13, 14, 15, 16, 17)
-
- 18. A method for rerouting communications between first and second nodes of a mesh network upon a failure in a first path between the first and second nodes, the method comprising rerouting the communications over a second path that was chosen prior to a failure, to carry the communications in the event of a failure, the second path being node and span disjoint from the first path and the communications in the second path being carried over at least one assigned channel in at least one transmission line between at least one pair of nodes of the second path, said rerouting including assigning said at least one channel after said failure occurred.
-
22. A method for use in a mesh network comprising nodes interconnected by links, the method comprising:
-
establishing a first communication path from a first node to a second node, the first communication path including at least two of said links and at least one intermediate node; directing communications traffic from the first end node to the second end node over the first path; and responsive to a failure in the first path, rerouting the traffic to a second communication path that had been identified prior to said failure as being the path over which the traffic would be rerouted in the event of a failure in the first path, the second path including at least two of said links and at least one intermediate node, the second path being node and span disjoint from the first path, and the traffic over the second path being directed over at least one assigned channel within a multichannel link of the second path that was assigned subsequent to said failure. - View Dependent Claims (23, 24, 37)
-
-
25. A method for use in a mesh network comprising nodes interconnected by transmission lines, at least two of the transmission lines being capable of carrying communication traffic in a plurality of channels, the method comprising:
-
establishing a first communication path between a first node and a second node, the first communication path including at least two of the transmission lines and at least one intermediate node; directing communications traffic from the first end node to the second end node over assigned channels of the transmission lines in the first path; and responsive to a failure in the first path, rerouting the traffic over assigned channels in the transmission lines of a second communication path between the first node and the second node, the second communication path having been chosen prior to said failure as being the path over which said communications traffic would be directed in the event of a failure in the first path, the second path having at least one intermediate node, the second path having no intermediate nodes or transmission lines in common with the first path, and at least one of the channels in the transmission lines of the second path being assigned subsequent to said failure. - View Dependent Claims (26, 27, 38)
-
- 28. A node for use as a first node in a mesh network of a type in which communications signals between said first node and a second node of said network over a first path through said network are rerouted over a second path through said network upon a failure in said first path, said second path having been identified prior to said failure as being the path over which said communications signals would be rerouted in the event of a failure in said first path, the second path being node and span disjoint from the first path, said first node being arranged to initiate, after said failure in said first path, an assignment of channels, within links connecting pairs of nodes in the second path, to carry said communications signals.
- 31. A method for use by a first node in a mesh network of a type in which communications signals between said first node and a second node of said network over a first path through said network are rerouted over a second path through said network upon a failure in said first path, said second path having been identified prior to said failure as being the path over which said communications signals would be rerouted in the event of a failure in said first path the second path being node and span disjoint from the first path, said method comprising initiating, after said failure in said first path, the assignment of channels, within links connecting pairs of nodes in the second path, to carry said communications signals.
- 34. A computer-readable medium on which are stored instructions that, when executed by one or more nodes in a mesh network, carry out a method for rerouting communications between first and second nodes of the network upon a failure in a first path between the first and second nodes, the method comprising rerouting the communications over a second path identified prior to said failure as being the path over which said communications would be rerouted in the event of a failure in the first path, the second path being node and span disjoint from the first path and the communications in the second path being carried over at least one assigned channel in at least one transmission line between at least one pair of nodes of the second path, said rerouting including assigning said at least one channel after said failure occurred.
Specification