Link Discovery and Verification Using Loss of Light

Abstract

Systems and methods for link discovery and verification that minimize the need for line termination resources to generate and interpret packets. According to one aspect of the present invention, a method for operating a first node in a data communication network to verify connectivity to a second node includes sending a request for verification of connectivity to the second node that identifies an IP address of the first node, a port of the first node, and an IP address of the second node. The method also includes toggling a signal emitted by the port, and notifying the second node of a toggling mode of the port. Finally, the method includes receiving a first message from the second node indicating whether the second node detected the toggling. The request for verification of connectivity is sent on a control channel via a control message separate from the signal and the first message.

1 . A method for operating a first node in a data communication network to verify connectivity to a second node in said data communication network, said method comprising:
 sending a request for verification of connectivity to said second node, said request for verification of connectivity identifying an IP address of said first node and an IP address of said second node, said request for verification of connectivity further identifying a port of said first node;   toggling a signal emitted by said port of said first node;   notifying said second node of a toggling mode of said port to facilitate connectivity verification; and   receiving a first message from said second node indicating whether said second node detected said toggling, said request for verification of connectivity identifying said first node being sent on a control channel via a control message separate from said signal and said first message being sent on said control channel.   
   
   
       2 . The method of  claim 1  wherein if said first message indicates that said second node detected said toggling, said first message identifies a property which the second node assigns said port of said first node. 
   
   
       3 . The method of  claim 1  further comprising:
 simultaneous with toggling of said signal emitted by said port of said first node, toggling another signal emitted by another port of said first node.   
   
   
       4 . The method of  claim 1  further comprising:
 sending notifications from said first node to said second node as said signal toggles on and off to facilitate connectivity verification.   
   
   
       5 . The method of  claim 1  wherein said signal comprises a selected wavelength component of a WDM signal. 
   
   
       6 . The method of  claim 1  wherein toggling comprises:
 turning said signal on and off aperiodically.   
   
   
       7 . The method of  claim 1  wherein toggling comprises:
 turning said signal on and off in accordance with a pseudorandomly selected sequence of intervals.   
   
   
       8 . A method for operating a first node in a data communication network to verify connectivity to a second node in said data communication network, said method comprising:
 receiving a request for verification of connectivity from said second node on a control channel, said request for verification of connectivity identifying an IP address of said second node and an IP address of said first node, said request for verification of connectivity further identifying a port at said second node;   detecting toggling of a signal received at a port of said first node;   verifying a link to said second node by matching said toggling to a known toggling mode of said port at said second node; and   sending a message to said second node indicating whether said first node matched said toggling to said known toggling mode, said message being sent on said control channel.   
   
   
       9 . The method of  claim 8  wherein if said message indicates that said first node matched said toggling to said known toggling mode, said message identifies a property which said first node assigns said port at said second node 
   
   
       10 . The method of  claim 8  further comprising:
 simultaneously with detecting toggling of said signal received at said port of said first node, detecting toggling of another signal received at another port of said first node; and   verifying an additional link to said second node by matching said toggling of another signal to a known toggling mode of an additional port at said second node.   
   
   
       11 . The method of  claim 8  wherein verifying comprises:
 receiving messages from said second node indicating when a toggled signal transmitted by said second node has been turned on and turned off; and   matching said messages to on and off states of said signal received at said port of said first node.   
   
   
       12 . The method of  claim 10  wherein receiving messages comprises:
 receiving messages through a control channel.   
   
   
       13 . An apparatus for operating a first node in a data communication network to verify connectivity to a second node in said data communication network, said apparatus comprising:
 a processor that sends a request for verification of connectivity to said second node, said processor being arranged to toggle a signal emitted by a port of said first node, said request for verification of connectivity being arranged to identify an IP address of said first node, an IP address of said second node, and said port; and   a control interface that notifies said second node of a toggling mode of said port to facilitate connectivity verification, wherein said request for verification is sent on a control channel via a control message separate from said signal.   
   
   
       14 . The apparatus of  claim 13  wherein said control interface sends notifications from said first node to said second node as said signal toggles on and off to facilitate connectivity verification. 
   
   
       15 . The apparatus of  claim 13  wherein said signal comprises a selected wavelength component of a WDM signal. 
   
   
       16 . The apparatus of  claim 13  wherein said processor toggles by turning said signal on and off aperiodically. 
   
   
       17 . The apparatus of  claim 13  wherein said processor toggles by turning said signal on and off in accordance with a pseudorandomly selected sequence of intervals. 
   
   
       18 . An apparatus for operating a first node in a data communication network to verify connectivity to a second node in said data communication network, said apparatus comprising:
 a photodetector that detects toggling of a signal received at a port of said first node; and   a processor that receives a request for verification of connectivity at said second node and verifies a link to said second node by matching said toggling to a known toggling mode of a port at said second node, wherein said request for verification comprises identification of an IP address of said first node, an IP address of said second node, and a port over which connectivity verification is to be performed and wherein said identification of said IP address of said first node, said IP address of said second node, and said port is received on a control channel via a control message separate from said signal.   
   
   
       19 . The apparatus of  claim 18  wherein said processor receives messages from said second node indicating when a toggled signal transmitted by said second node has been turned on and turned off and matches said messages to on and off states of said signal received at said port of said first node. 
   
   
       20 . The apparatus of  claim 18  wherein said messages are received through a control channel. 
   
   
       21 . An apparatus for operating a first node in a data communication network to verify connectivity to a second node in said data communication network, said apparatus comprising:
 means for sending a request or verification of connectivity to said second node, said request for verification of connectivity identifying an IP address of said first node and an IP address of said second node, said request for verification of connectivity further identifying a port of said first node;   means for toggling a signal emitted by said port of said first node;   means for notifying said second node of a toggling mode of said port to facilitate connectivity verification; and   means for receiving a first message from said second node indicating whether said second node detected said toggling, said request for verification of connectivity identifying said first node being sent on a control channel via a control message separate from said signal and said first message being sent on said control channel.   
   
   
       22 . The apparatus of  claim 21  wherein if said first message indicates that said second node detected said toggling, said first message identifies a property which the second node assigns said port of said first node. 
   
   
       23 . The apparatus of  claim 22  further comprising:
 means for sending notifications from said first node to said second node as said signal toggles on and off to facilitate connectivity verification.   
   
   
       24 . An apparatus for operating a first node in a data communication network to verify connectivity to a second node in said data communication network, said apparatus comprising:
 means for receiving a request for verification of connectivity from said second node on a control channel, said request for verification of connectivity identifying an IP address of said second node and an IP address of said first node;   means for detecting toggling of an optical signal received at a port of said first node; and   means for verifying a link to said second node by matching said toggling to a known toggling mode of said port at said second node, wherein said request for verification comprises identification of an IP address of said first node, an IP address of said second node, and a port over which connectivity verification is to be performed and wherein said identification of said IP address of said first node, said IP address of said second node, and port information is received on a control channel via a control message separate from said signal.   
   
   
       25 . A computer program product for operating a first node in a data communication network to verify connectivity to a second node in said data communication network, said computer program product comprising:
 code that receives a request for verification of connectivity from said second node, said request for verification of connectivity identifying an IP address of said first node and an IP address of said second node;   code that detects toggling of a signal received at a port of said first node;   code that verifies a link to said second node by matching said toggling to a known toggling mode of a port at said second node, wherein said request for verification of connectivity identifying said IP address of said first node, said IP address of said second node, and said port of said second node is sent on a control channel via a control message separate from said signal; and   a computer-readable storage medium that stores the codes.   
   
   
       26 . A computer program product for operating a first node in a data communication network to verify connectivity to a second node in said data communication network, said computer program product comprising:
 code that is configured for sending a request for verification of connectivity to said second node on a control channel, said request for verification of connectivity identifying an IP address of said second node and an IP address of said first node;   code that toggles a signal emitted by a port of said first node;   code that notifies said second node of a toggling mode of said port to facilitate connectivity verification, wherein said request for verification comprises identification of said IP address of said first node, said IP address of said second node, and said port at said second node over which connectivity verification is to be performed and wherein said identification of said IP address of said first node, said IP address of said second node, and said port at said second node is received on a control channel via a control message separate from said signal; and   a computer-readable storage medium for storing the codes.