Optical Impairment Aware Path Computation Architecture in PCE Based Network

Abstract

An apparatus comprising at least one processor configured to implement a method comprising receiving a path computation request comprising at least one path computation constraint, and determining whether there is a path through an optical network that satisfies the path computation constraints. Also disclosed is an apparatus configured to process a data structure comprising a flags field comprising at least one flag having one of an active state or an inactive state, wherein each flag is representative of an optical quality constraint.

1 . An apparatus comprising:
 at least one processor configured to implement a method comprising:   receiving a path computation request comprising at least one path computation constraint; and   determining whether there is a path through an optical network that satisfies the path computation constraints.   
   
   
       2 . The apparatus of  claim 1 , wherein the method further comprises sending a reply comprising the path when there is at least one path through the optical network that satisfies the path computation constraints. 
   
   
       3 . The apparatus of  claim 2 , wherein the method further comprises sending a reply comprising an error message when there is not a path through the optical network that satisfies the path computation constraints. 
   
   
       4 . The apparatus of  claim 3 , wherein the method further comprises forwarding the request to a path computation element (PCE) associated with another optical network domain. 
   
   
       5 . The apparatus of  claim 4 , wherein the request forwarded to the PCE does not comprise the path. 
   
   
       6 . The apparatus of  claim 4 , wherein the reply comprises at least one path for the second optical network. 
   
   
       7 . The apparatus of  claim 3 , wherein the optical network comprises a plurality of layers, wherein determining whether there is a path through the optical network comprises analyzing less than all of the layers, and wherein the method further comprises forwarding the request to a path computation element (PCE) associated with at least some of the unanalyzed layers. 
   
   
       8 . The apparatus of  claim 7 , wherein the request forwarded to the PCE comprises the path that satisfies the path computation constraints for the analyzed layers. 
   
   
       9 . The apparatus of  claim 7 , wherein there is not a path through the optical network that satisfies the path computation constraints when there is not a path that satisfies the path computation constraints for all of the layers. 
   
   
       10 . The apparatus of  claim 3 , wherein the optical network comprises a plurality of layers, wherein determining whether there is a path through the optical network comprises analyzing all of the layers. 
   
   
       11 . The apparatus of  claim 10 , wherein the optical network comprises a plurality of network elements (NEs), and wherein the topology between the NEs is not identical in all of the layers. 
   
   
       12 . The apparatus of  claim 1 , wherein the path computation constraint are selected from the group consisting of: optical signal-to-noise ratio (OSNR), amplifier spontaneous emission (ASE), polarization mode dispersion (PMD), polarization-dependent loss (PDL), coherent optical crosstalk, incoherent optical crosstalk, effective pass-band, gain non-uniformity, gain transients, chromatic dispersion, and combinations thereof. 
   
   
       13 . The apparatus of  claim 1 , wherein the path is present in an optical quality constraint object. 
   
   
       14 . An apparatus configured to process a data structure comprising:
 a flags field comprising at least one flag having one of an active state or an inactive state, wherein each flag is representative of an optical quality constraint.   
   
   
       15 . The apparatus of  claim 14 , wherein the data structure further comprises a type-length-value (TLV) data structure for at least some of the flags having the active state. 
   
   
       16 . The apparatus of  claim 14 , wherein each flag is about one bit in length, is in the active state when the bit is a one, and is in the inactive state when the bit is a zero. 
   
   
       17 . The apparatus of  claim 14 , wherein the last flag in the flags field is a polarization mode dispersion (PMD) flag. 
   
   
       18 . The apparatus of  claim 14 , wherein the second-to-last flag in the flags field is an optical signal-to-noise ratio (OSNR) flag. 
   
   
       19 . The apparatus of  claim 14 , wherein the flags having active states have different meanings depending on whether the flag is in a request message or a reply message. 
   
   
       20 . The apparatus of  claim 14 , wherein the optical quality constraints are selected from the group consisting of: optical signal-to-noise ratio (OSNR), amplifier spontaneous emission (ASE), polarization mode dispersion (PMD), polarization-dependent loss (PDL), coherent optical crosstalk, incoherent optical crosstalk, effective pass-band, gain non-uniformity, gain transients, chromatic dispersion, and combinations thereof.