Routing method for dynamic wdm optical networks with wavelength continuity restrictions

Abstract

The invention relates to a novel method for determining the set of routes that allow each network user to transmit. The method is more efficient than the existing methods, in terms of number of wavelengths, and due to the fixed routing strategy used, its implementation is simple, and its online operation is very fast.

1 . A routing method for a dynamic wavelength division multiplexing (WDM) optical network having wavelength continuity constraints, CHARACTERIZED in that the method comprises:
 obtaining, by means of a processor, the topology of said dynamic WDM optical network having wavelength continuity constraints, stored in a topology database, said dynamic WDM optical network being represented by N network nodes and L links connecting said N nodes;   obtaining, by means of said processor, a plurality of users of said network, wherein a user of said plurality is defined as a source node, a destination node, and a traffic load associated with said user;   obtaining, by means of said processor, a plurality of non-operational routes, said plurality of non-operational routes corresponding to said plurality of users; and storing said plurality of non-operational routes in a non-operational routes database, wherein said non-operational routes are stored in said non-operational routes database sorted from shorter to longer length and, for those of equal length, from lowest to highest traffic load;   storing, in an operational routes database, the routes having length equal to 1 and removing said route from said non-operational routes database;   calculating, by means of said processor, the cost of each link of said network using the information from said operational routes database;   calculating, by means of said processor, a cheapest route corresponding to the user of the first non-operational route of said non-operational routes database, using the information corresponding to the cost of each link;   storing said cheapest route in said operational routes database and removing said non-operational route corresponding to said user of said non-operational routes database;   repeating the above two steps until there are no non-operational routes in said non-operational routes database; and   transmitting information through said network using said routes stored in said operational routes database.   wherein said processor calculates the cost of each link   by the formula:
     =   
   wherein   is the traffic load of the link   and  ρ  is the average traffic load of said Network.   
     
     
         2 . The method of  claim 1 , CHARACTERIZED in that said non-operational routes are obtained by means of the Dijkstra algorithm. 
     
     
         3 . The method of  claim 1 , CHARACTERIZED in that said cheapest paths are obtained by means of the Dijkstra algorithm weighted by the cost of each link. 
     
     
         4 . The method of claim 1 , CHARACTERIZED in that the traffic load of each link  ,  , is obtained by the formula: 
       
         
           
             
               
                 ρ 
                 ℓ 
               
               = 
               
                 
                   ∑ 
                   
                     u 
                     ℓ 
                   
                 
                 ⁢ 
                 
                   ρ 
                   u 
                 
               
             
           
         
         wherein   is the set of users whose operational routes use the link   and ρ u  is the traffic load of a user u. 
       
     
     
         5 . The method of claim 1 , CHARACTERIZED in that said average traffic load,  ρ , is obtained by the formula 
       
         
           
             
               
                 
                   ρ 
                   ¯ 
                 
                 = 
                 
                   
                     
                       ∑ 
                       ℓ 
                     
                     ⁢ 
                     
                       ρ 
                       ℓ 
                     
                   
                   L 
                 
               
               .