Methods and apparatuses for improved Ethernet path selection using optical levels

Abstract

Methods and apparatuses are provided to employ an enhanced Loss of Signal (ELOS) function in network equipment (NE) such as an Ethernet switch that is coupled to an optical path by a transceiver (e.g., an SFP). Diagnostics such as optical path receive (Rx) level from the transceiver are used by the ELOS function to regenerate LOS status from the transceiver when either LOS or designated low Rx level conditions exist. By generating an enhanced LOS (ELOS) on a designated low Rx level, the ELOS function ensures a failing data path is removed before an undesirable amount of errors occur to enhance Ethernet path selection and improve Carrier Ethernet quality of service.

What is claimed is: 
     
       1. A method of enhanced monitoring for optical signal level degradation comprising:
 obtaining at least one diagnostic level from a small form-factor pluggable (SFP) transceiver connected to an optical path, the diagnostic level comprising at least a SFP loss of signal (LOS) assertion level of the SFP transceiver that is designated by a SFP transceiver manufacturer and corresponds to a signal level on the optical path at which the SFP transceiver asserts a LOS indication to a host network equipment (NE) device to which the SFP transceiver is connected; 
 determining at least one parameter corresponding to a low receive level threshold for an optical path, the low receive level threshold having a value that is above the SFP LOS assertion level by a designated amount; 
 receiving a Receive (Rx) level for the optical path from the transceiver; 
 determining if the received Rx level satisfies the low receive level threshold; 
 generating an enhanced LOS (ELOS) indication when the received Rx level reaches the low receive level threshold; and 
 asserting a LOS for the host NE device when the generation of the ELOS indication occurs, and asserting a LOS for the host NE device when the SFP transceiver asserts a LOS indication in response to detecting the Rx level at the SFP LOS assertion level. 
 
     
     
       2. The method of  claim 1 , further comprising selecting a diagnostic level of the SFP transceiver to be a reference diagnostic level, wherein the parameter is a margin designating a selected value above, below, or at the reference diagnostic level. 
     
     
       3. The method of  claim 2 , further comprising designating the reference diagnostic level and the margin such that the low receive level threshold corresponds to an alarm level of the SFP transceiver. 
     
     
       4. The method of  claim 2 , wherein at least one of the reference diagnostic level and the parameter is user-settable. 
     
     
       5. The method of  claim 2 , wherein:
 the obtaining the at least one diagnostic level comprises obtaining a Rx sensitivity of the SFP transceiver; 
 the determining at least one parameter comprises
 applying respective margins to the Rx sensitivity to generate values representing the low receive level threshold and a recovery threshold, respectively, and 
 storing the generated values; and 
 
 the determining comprises if the received Rx level satisfies the low receive level threshold or the recovery threshold, the ELOS being asserted when the received Rx level reaches the low receive level threshold and the ELOS being de-asserted when the received Rx level reaches the recovery threshold. 
 
     
     
       6. The method of  claim 5 , wherein the low receive level threshold is a value x dBm above the SFP LOS assertion level, and the recovery threshold is a value y dBm above the low receive level threshold, and y>x>SFP LOS assertion level of the SFP transceiver. 
     
     
       7. The method of  claim 1 , further comprising designating a parameter corresponding to a recovery threshold for the optical path, the recovery threshold being a value that is greater than the low receive level threshold. 
     
     
       8. The method of  claim 7 , further comprising de-asserting the ELOS when the received Rx level satisfies the recovery threshold. 
     
     
       9. The method of  claim 1 , further comprising performing a logical OR operation using the enhanced Loss of Signal (ELOS) generated when the received Rx level reaches the low receive level threshold, and a Loss of Signal provided by the SFP transceiver when the received Rx level reaches the SFP LOS assertion level. 
     
     
       10. The method of  claim 9 , further comprising transmitting an output of the logical OR operation to provide a LOS, alarm or fault indication to a network device in which the SFP transceiver is deployed. 
     
     
       11. The method of  claim 1 , comprising storing the parameter in a memory device that is not integral to the SFP transceiver. 
     
     
       12. A non-transitory computer-readable medium storing a program for enhanced monitoring of optical signal level degradation comprising:
 a first set of instructions for obtaining at least one diagnostic level from a small form-factor pluggable (SFP) transceiver connected to an optical path, the diagnostic level comprising at least a SFP loss of signal (LOS) assertion level of the SFP transceiver that is designated by its SFP transceiver manufacturer and corresponds to a signal level on the optical path at which the SFP transceiver asserts a LOS indication to a host network equipment (NE) device to which the SFP transceiver is connected; 
 a second set of instructions for determining at least one parameter corresponding to a low receive level threshold for an optical path, the low receive level threshold having a value that is above the SFP LOS assertion level by a designated amount; 
 a third set of instructions for receiving a Receive (Rx) level for the optical path from the transceiver and determining if the received Rx level satisfies the low receive level threshold; 
 a fourth set of instructions for generating an enhanced LOS (ELOS) indication when the received Rx level reaches the low receive level threshold; and 
 a fifth set of instructions for asserting a LOS for the host NE device when the generation of the ELOS indication occurs, and asserting a LOS for the host NE device when the SFP transceiver asserts a LOS indication in response to detecting the Rx level at the SFP LOS assertion level. 
 
     
     
       13. The non-transitory computer-readable medium of  claim 12 , wherein
 the first set of instructions comprises instructions for obtaining a Rx sensitivity of the SFP transceiver; 
 the second set of instructions comprises instructions for
 storing a parameter corresponding to a recovery threshold for the optical path, 
 calculating values representing the low receive level threshold and a recovery threshold using respective margins with the Rx sensitivity, and 
 storing the calculated values; and 
 
 the third set of instructions comprises instructions for determining if the received Rx level satisfies the low receive level threshold or the recovery threshold, the ELOS being asserted when the received Rx level reaches the low receive level threshold and the ELOS being de-asserted when the received Rx level reaches the recovery threshold. 
 
     
     
       14. The non-transitory computer-readable medium of  claim 13 , wherein the low receive level threshold is a value x dBm above the SFP LOS assertion level, and the recovery threshold is a value y dBm above the low receive level threshold, and y>x>SFP LOS assertion level of the SFP transceiver. 
     
     
       15. The non-transitory computer-readable medium of  claim 12 , further comprising a fourth set of instructions for generating a prompt via a user interface for the user to enter a user-settable value for the parameter and storing the user-settable value.