Method of allocating bandwidth in an optical network

Abstract

Proposed is a method for allocating bandwidth in an optical network. A bandwidth grid containing first bandwidth slots of a lower bandwidth and higher bandwidth slots of a higher bandwidth is provided. A set of requests for respective data transmission connections with respective data rates and respective shortest path metrics is provided. Shorter distances, over which a data signal may be transmitted transparently at the respective data rate within the lower bandwidth, and longer distances, over which a data signal may be transmitted transparently at the respective data rate within the higher bandwidth, are provided. Bandwidth slots of the lower bandwidth for those of the data transmission connections, whose respective shortest path metric is smaller than their respective shorter distance, are allocated. Finally, bandwidth slots of the lower or the higher bandwidth are allocated for the further data transmission connections, using respective numbers of necessary OEO regenerations.

The invention claimed is: 
     
       1. A method of allocating bandwidth in an optical network, comprising:
 generating a bandwidth grid containing first bandwidth slots of a lower bandwidth and second bandwidth slots of a higher bandwidth which is twice the lower bandwidth, wherein one of said second bandwidth slots represents a same bandwidth on said bandwidth grid as two of said first bandwidth slots, 
 providing a set of requests for respective data transmission connections with respective data rates and respective shortest path metrics, 
 providing for said data transmission connections respective shorter distances, over which a data signal may be transmitted transparently at the respective data rate within said lower bandwidth, and respective longer distances, over which a data signal may be transmitted transparently at the respective data rate within said higher bandwidth, 
 allocating bandwidth slots of said lower bandwidth for those of said data transmission connections whose respective shortest path metric is smaller than or equal to their respective shorter distance, and 
 allocating bandwidth slots of said lower bandwidth or said higher bandwidth for the further of said data transmission connections whose respective shortest path metric is greater than their respective shorter distance, using respective first and second numbers of necessary optical-electrical-optical regenerations for transmitting data signals at the respective data rates via said further data transmission connections using said lower bandwidth or said higher bandwidth respectively. 
 
     
     
       2. The method according to  claim 1 , wherein the step of allocating bandwidth slots of said lower bandwidth or said higher bandwidth for said further data transmission connections comprises:
 determining a necessary allocation of bandwidth slots of said higher bandwidth for said further data transmission connections, 
 in case an allocation of bandwidth slots of said higher bandwidth for said further data transmission connections is not feasible, determining a link of said optical network with the greatest number of said further data transmission connections, for which bandwidth slots of said higher bandwidth cannot be allocated, and 
 allocating bandwidth slots of said lower bandwidth or said higher bandwidth for said further data transmission connections on said link, using said respective first and second numbers of necessary optical-electrical-optical regenerations for transmitting data signals at the respective data rates via said further data transmission connections within said lower bandwidth or said higher bandwidth respectively. 
 
     
     
       3. The method according to  claim 1 , wherein said step of allocating bandwidth slots of said lower bandwidth or said higher bandwidth for said further data transmission connections further comprises:
 determining for said further data transmission connections said respective first and second numbers of necessary optical-electrical-optical regenerations. 
 
     
     
       4. The method according to  claim 3 , wherein the step of allocating bandwidth slots of said lower bandwidth or said higher bandwidth for said further data transmission connections on said link further comprises:
 allocating bandwidth slots of said lower bandwidth for a first subset of said further data transmission connections, and 
 allocating bandwidth slots of said higher bandwidth for a second subset of said further data transmission connections, 
 wherein for data transmission connections of said first subset, respective differences between said respective first and said respective second numbers of necessary optical-electrical-optical regenerations are smaller than for data transmission connections of said second subset. 
 
     
     
       5. The method according to  claim 3 , wherein said step of allocating bandwidth slots of said lower bandwidth or said higher bandwidth for said further data transmission connections on said link further comprises:
 allocating bandwidth slots of said lower bandwidth for that of said further data transmission connections, for which respective differences between said respective first and said respective second necessary numbers of necessary optical-electrical-optical regenerations are smallest. 
 
     
     
       6. The method according to  claim 5 , further comprising:
 determining a necessary allocation of bandwidth slot of said higher bandwidth for the remaining of said further data transmission connections on said link, and 
 in case an allocation of bandwidth slots of said higher bandwidth for the remaining of said further data transmission connections on said link is feasible, allocating bandwidth slots of said higher bandwidth for the remaining of said further data transmission connections on said link. 
 
     
     
       7. The method according to  claim 6 ,
 in case, an allocation of bandwidth slots of said higher bandwidth for the remaining of said further data transmission connections on said link is not feasible, returning to said step of determining that link of said optical network with the greatest number of said further data transmission connections, for which bandwidth slots of said higher bandwidth cannot be allocated. 
 
     
     
       8. The method according to  claim 3 , wherein said respective first and second numbers of necessary optical-electrical-optical regenerations are determined for said further data transmission connections using
 said respective data rates, 
 said shortest path metrics, 
 a predefined modulation method, and 
 a maximum bit error rate, which shall not be exceeded at a receiving end of the respective data transmission connection. 
 
     
     
       9. The method according to  claim 1 , further comprising determining a first reach over which said data signal may be transmitted transparently with properties of a link over which said data signal is to be transmitted and a chosen modulation format, wherein a transparent transmission is one in which said data signal is not regenerated by means of optical-electrical-optical conversion. 
     
     
       10. The method according to  claim 1 , wherein an allocation of bandwidth slots is carried out using messages of a Resource Reservation Protocol. 
     
     
       11. The method according to  claim 1 , comprising:
 allocating bandwidth slots of said lower bandwidth or said higher bandwidth for the further of said data transmission connections, whose respective shortest path metric is greater than their respective shorter distance and smaller than or equal to their respective longer distance, using respective first and second numbers of necessary optical-electrical-optical regenerations for transmitting data signals at the respective data rates via said further data transmission connections within said lower bandwidth and said higher bandwidth respectively. 
 
     
     
       12. The method according to  claim 1 , wherein the step of providing said set of requests for respective data transmission connections comprises determining said respective shortest path metrics for said data transmission connections.