Suprvisory channel in an optical network system

Abstract

There is provided an optical network element for use in a node of an optical network including a plurality of nodes which are interconnected so as to be capable of carrying traffic between selected nodes, comprising a local network management system including means for building up a supervisory connection between the network element and at least a network element of a further node of the optical network. The local network management system is installed to support an arbitrary network topology and to build up a survivable supervisory connection to at least one predetermined other node of the network so as the network element could be integrated in an optical network with arbitrary topology. An optical network and a method of providing a supervisory network are also provided.

1 . An optical network element for use in a node of an optical network that includes a plurality of nodes that are interconnected so as to be capable of carrying traffic between selected nodes, the optical network element comprising: 
 a local network management system having means for building up a supervisory connection between the optical network element of a first node of said plurality of nodes and at least a network element of a second node of said plurality of nodes of the optical network;    wherein the local network management system is supports an arbitrary network topology and builds up the supervisory connection to at least one predetermined other node of the plurality of nodes of the network so that the network element can be integrated in an optical network with arbitrary topology,    wherein the supervisory connection is a redundant connection through two or more paths, and    wherein the local network management system monitors the status of all paths of the redundant supervisory connection, and establishes an alternative route for a specific supervisory connection in the event of an impairment of the specific supervisory connection.    
     
     
         2 . The optical network element according to  claim 1 , wherein the local network management system provides self healing of the supervisory connection for an impairment of the supervisory connection.  
     
     
         3 . The optical network element according to  claim 1 , further comprising a software module associated with the network management system, that acts as a node manager and includes a software agents selected from the group consisting of: 
 a start-up manager,    a process, thread and session manager,    a supervisory channel manager,    a hardware devices manager,    a status, fault, and events monitor,    a database system manager,    at least one user interfaces, and    a system resources and functions manager, and any combinations thereof.    
     
     
         4 . The optical network element according to  claim 1  wherein the local network management system can be configured by standard software protocols.  
     
     
         5 . The optical network element according to  claim 1 , wherein the local network management system automatically discovers network elements of adjacent network nodes of said plurality of nodes and to exchanges Link State Advertisement with the adjacent network elements of the adjacent network nodes of said plurality of nodes.  
     
     
         6 . The optical network element according to  claim 1 , further comprising: 
 at least one back-plane including a plurality of electrical transmission lines running across the back-plane and a plurality of electrical terminals connected to the plurality of electrical transmission lines;    a plurality of line-card slices having line-card slice electrical terminals, wherein each line-card slice is attached to the back-plane, so that the line-card slice electrical terminals are electrically connected to the electrical terminals of the plurality of electrical terminals of the back-plane;    at least one optical receiver associated with at least one of the plurality of line-card slices for receiving optical signals from the network;    at least one opto-electrical converter integrated in or optically connected to the optical receiver with electrical terminals of the at least one opto-electrical converter and;    at least one optical transmitter associated with at least one of the plurality of line-card slices for transmitting optical signals to the network;    at least one electro-optical converter integrated in or optically connected to the optical transmitter with electrical terminals of the at least one opto-electrical converter; and    at least one supervisory card plugged to the back-plane capable of functions selected from the group consisting of transmitting supervisory signals, processing supervisory signals, and a combination thereof,    wherein at least one of the electrical terminals of said plurality of electrical terminals are switch terminals that provide selected and reconfigurable electrical interconnections among components of at the least one line-card slice selected from the group consisting of the receiver, the transmitter, the converter, and any combination thereof,    wherein the interconnections are accomplished by devices selected from the group consisting of an electrical switches and at least one electrical cross-connect, and    wherein the supervisory card is electrically connected via the electrical transmission lines of the back-plane to a one of said plurality of line-card slices by a connection selected from the group consisting of directly connection and a cross-connect.    
     
     
         7 . The optical network element according to  claim 6 , further comprising a node PC, that is plugged to the back-plane, that provides and/or receives an electrical supervisory signal, that is transmitted to or from the supervisory card.  
     
     
         8 . The optical network element according to  claim 7 , wherein the node PC is connected to the network as a standalone computer sub-system.  
     
     
         9 . The optical network element according to  claim 1 , wherein the supervisory connection provides at least a part of an in-band supervisory data by using electrical multiplexing and demultiplexing of the supervisory data with client's data, carried by the optical network.  
     
     
         10 . The optical network element according to  claim 1 , wherein the supervisory connection provides at least a part of an out-of-band supervisory data multiplexed onto or demultiplexed from one or more optical fiber links of the optical network by a device selected from the group consisting of a WDM coupler and a filter.  
     
     
         11 . An optical network that includes a plurality of nodes that are interconnected so as to be capable of carrying traffic between selected nodes, comprising: 
 a plurality of network elements according to  claim 1;     a network management system carried out by at least one of the local network management systems of the network elements; and    supervisory connections between predetermined network elements.    
     
     
         12 . The optical network according to  claim 11 , wherein the network management system provides establishment of a direct logical supervisory connection between any desired pair of nodes of said plurality of nodes interconnected by the supervisory connection.  
     
     
         13 . The optical network according to  claim 12 , wherein at least one of the direct logical supervisory connections are carried at least in part by a technique selected from the group consisting of time division multiplexing, statistical multiplexing, and a combination thereof, over a single physical supervisory connection between a pair of nodes.  
     
     
         14 . The optical network according to  claim 11 , wherein the network management system provides a function selected from the group consisting of: 
 hardware fault detection on all of the supervisory connections,    software error detection on all of the supervisory connections,    auto-recovery of the supervisory connections,    fault-tolerant supervisory connections, redundant supervisory connections,    automatic discovery of nodes of the optical network, and    any combinations thereof.    
     
     
         15 . A method of providing a supervisory network in an optical network having an arbitrary network topology that includes a plurality of nodes that are interconnected so as to be capable of carrying traffic between selected nodes, the method comprising: 
 automatically discovering the network topology; and    establishing of redundant supervisory connections between predetermined nodes of said plurality of nodes of the network;    monitoring the status of all paths of the redundant supervisory connection; and    establishing an alternative route for a specific supervisory connection in the event of an impairment of the specific supervisory connection.    
     
     
         16 . The method according to  claim 15 , wherein each node of the plurality of nodes of the network includes a local network management system, wherein the local network management system of each of said plurality of nodes communicates with the local network management system of adjacent nodes of said plurality of nodes and exchanges Link State Advertisements, so that each node of said plurality of nodes discovers all of the adjacent nodes of said plurality of nodes and by utilizing the exchanged Link State Advertisements a routing table is generated that is stored in at least one of the plurality of nodes.  
     
     
         17 . The method according to  claim 16 , wherein the node manager of each node of said plurality of nodes executes a single OSPF, wherein the OSPF in each node of said plurality of nodes communicates with the node manager of the adjacent nodes of said plurality of nodes so that the OSPF converges on the topology of the network.  
     
     
         18 . The method according to  claim 15 , further comprising monitoring the status of the supervisory connections and configuring alternative routes in the event of link failure.  
     
     
         19 . The method according to  claim 15 , further comprising: 
 sending supervisory data that is carried by the optical network for use in a supervisory management layer of the network in the form of messages through at least one available redundant connections from a sending end to a receiving end of the network;    giving each message a sequence number; and    19.3 discarding duplicate messages on the receiving end and passing only one of several arriving messages on to the supervisory management layer.    
     
     
         20 . The method according to claims  16 , wherein the network management is carried out by the node manager present in the local management systems in at least one node of the network.  
     
     
         21 . The method according to  claim 15 , further comprising carrying out a function on all supervisory connections, wherein the function is selected from the group consisting of hardware fault detection, software error detection, and a combination thereof.  
     
     
         22 . The method according to  claim 15 , further comprising carrying out a function on all supervisory connections, wherein the function is selected from the group consisting of auto-recovery and self-healing.  
     
     
         23 . The method according to  claim 15 , further comprising the steps of: 
 monitoring a status of each supervisory connection by sending keep-alive messages at predetermined intervals of time between the predetermined nodes and by resending reply-messages on receiving of a keep-alive message; and    closing down the supervisory connection between the predetermined nodes in the event that the reply-message in response to the keep-alive message is not received within a predetermined time period.    
     
     
         24 . The method according to  claim 23 , further comprising the step of automatically re-establishing a new connection between the predetermined nodes via an alternative connection path.  
     
     
         25 . The method according to claims  15 , further comprising storing information concerning the network status in the local network management system of at least one predetermined node, wherein the information is selected from a group consisting of predetermined information, real time information, and a combination thereof.  
     
     
         26 . The optical network element according to  claim 3 , wherein the at least one user interface is selected from the group consisting of GUI, console and TL1.  
     
     
         27 . The optical network element according to  claim 4 , wherein the standard software protocol is selected from the group consisting of OSPF, MPLS, and a combination thereof.  
     
     
         28 . The optical network element according to  claim 6 , wherein each line-card slice is connected to the back-plane by an attachment selected from the group consisting of direct attachment and a plug-in module.  
     
     
         29 . The method according to  claim 16 , wherein the local network management system includes at least one node manager.  
     
     
         30 . The method according to  claim 18 , wherein monitoring the status of the supervisory connections is accomplished by OSPF.