Fiber optic synchronous digital hierarchy telecommunication network provided with a protection system shared on the network

Abstract

A fiber optic synchronous digital hierarchy telecommunication network provided with a protection system shared on the network is described, which comprises spans of pairs of optical fibers (N× 2 F) having network elements (N× 2 F-SDHNE) interposed therebetween, wherein the spares of pairs of optical fibers have a variable number N (N=1, 2, 3, . . . ) of pairs, and the network elements (N× 2 F-SDHNE) feature variable interconnection capability between said spans, so that several spans having number N of pairs of optical fiber even different can be connected to at least some of said network elements.

1 . A fiber optic network, including network elements comprising optical interfaces for receiving optical fibers, and fiber optic spans interposed between the network elements to form a ring, each network element being connected to adjacent network elements through said fiber optic spans allowing communication therebetween; 
 wherein said fiber optic spans comprise: 
 at least two spans having a first number of fibers; and  
 at least one span having a second number of fibers, the second number being different from the first number;  
   further wherein said network elements comprise: 
 at least one network element interposed between spans having said first number of fibers; and  
 at least one network element connected to a span having said second number of fibers.  
   
     
     
         2 . A network according to  claim 1 , wherein every network element realizes the following types of non-blocking connections: 
 cross-connection between fibers of the same span;    cross-connection between fibers of different spans, from any span towards any other span;    connections between said fibers and local ports for local data flows at a bit rate lower than the bit rate between the network elements.    
     
     
         3 . An optical ring network, comprising: 
 a plurality of network elements; and    plural fiber optic spans interposed between the network elements to form said ring, each network element being connected to adjacent network elements through said fiber optic spans allowing communication therebetween, wherein a non-blocking cross-connection is realized between fibers of a same span.    
     
     
         4 . An optical ring network, comprising: 
 a plurality of network elements; and    plural fiber optic spans interposed between the network elements to form said ring, each network element being connected to adjacent network elements through said fiber optic spans allowing communication therebetween, wherein a non-blocking cross-connection is realized between fibers of different spans from any span towards any other span.    
     
     
         5 . An optical ring network, comprising: 
 a plurality of network elements; and    plural fiber optic spans, each of a plurality of fibers, interposed between the network elements to form said ring, each network element being connected to adjacent network elements through said fiber optic spans allowing communication at a same bit rate therebetween, wherein non-blocking connections are makeable between said fibers and local ports for local data flows at a bit rate lower than said same bit rate between said network elements.    
     
     
         6 . A network according to  claim 1 , wherein said fiber optic spans further comprise at least one span having a third number of fibers, the third number being higher than the second number.  
     
     
         7 . A network according to  claim 1 , further wherein said at least one network element that is connected to a span having said second number of fibers is also connected to at least one span having said first number of fibers.  
     
     
         8 . A network according to  claim 1 , further wherein said at least one network element that is connected to a span having said second number of fibers is also connected to a further span having said second number of fibers.  
     
     
         9 . A network according to  claim 6 , further wherein said network elements comprise at least one network element connected to a span having said third number of fibers and to at least one span having said first number of fibers.  
     
     
         10 . A network according to  claim 6 , further wherein said network elements comprise at least one network element connected to a span having said third number of fibers and to at least one span having said second number of fibers.  
     
     
         11 . A network according to  claim 6 , further wherein said network elements comprise at least one network element connected to a span having said third number of fibers and to a span having said third number of fibers.  
     
     
         12 . A network according to  claim 1 , wherein said at least one network element that is connected to a span having said second number of fibers provides for a cross-connection capability between fibers of the same span.  
     
     
         13 . A network according to  claim 1 , wherein said at least one network element that is connected to a span having said second number of fibers provides for a cross-connection capability between fibers of different spans.  
     
     
         14 . A network according to  claim 3 , wherein said at least one network element that is connected to a span having said second number of fibers provides for a connection capability between said fibers and local ports for local data flows at a bit rate lower than the bit rate between the network elements.  
     
     
         15 . A network element for use in a fiber optic network including network elements and fiber optic spans interconnecting the network elements to form a ring, said fiber optic spans including at least two spans having a first number of fibers; and at least one span having a second number of fibers, with the second number being higher than the first number; said network element realizing the following types of non-blocking connections: 
 cross-connection between fibers of the same span;    cross-connection between fibers of different spans, from any span towards any other span;    connections between said fibers and local ports for local data flows at a bit rate lower than the bit rate between the network elements.    
     
     
         16 . A method for making a fiber optic network, the method comprising the step of interposing fiber optic spans between network elements to form a ring, wherein said network elements comprise optical interfaces for receiving optical fibers and wherein each network element is connected to adjacent network elements through said fiber optic spans allowing communication therebetween, wherein: 
 at least two of said spans have a first number of fibers, and at least one of said spans has a second number of fibers, the second number being different from the first number; and    said step of providing network elements comprises providing at least one network element interposed between spans having said first number of fibers, and providing at least one network element connected to a span having said second number of fibers.    
     
     
         17 . A method according to  claim 16 , wherein the step of providing network elements comprises providing network elements realizing the following types of non-blocking connections: 
 cross-connection between fibers of the same span;    cross-connection between fibers of different spans, from any span towards any other span; and    connections between said fibers and local ports for local data flows at a bit rate lower than the bit rate between the network elements.    
     
     
         18 . A method according to  claim 16 , wherein said fiber optic spans further comprise at least one span having a third number of fibers, the third number being higher than the second number.  
     
     
         19 . A method according to  claim 16 , further comprising connecting said at least one network element that is connected to a span having said second number of fibers also to at least one span having said first number of fibers.  
     
     
         20 . A method according to  claim 16 , further comprising connecting said at least one network element that is connected to a span having said second number of fibers also to a further span having said second number of fibers.  
     
     
         21 . A method according to  claim 18 , wherein said interposing step further comprises connecting at least one network element connected to a span having said third number of fibers also to at least one span having said first number of fibers.  
     
     
         22 . A method according to  claim 18 , wherein said interposing step further comprises connecting at least one network element connected to a span having said third number of fibers also to at least one span having said second number of fibers.  
     
     
         23 . A method according to  claim 18 , wherein said interposing step further comprises connecting at least one network element connected to a span having said third number of fibers also to a span having said third number of fibers.  
     
     
         24 . A method according to  claim 16 , wherein said first number of fibers is two and said second number of fibers is four.  
     
     
         25 . A method according to  claim 16 , wherein said at least one network element that is connected to a span having said second number of fibers provides for a cross-connection capability between fibers of the same span.  
     
     
         26 . A method according to  claim 16 , wherein said at least one network element that is connected to a span having said second number of fibers provides for a cross-connection capability between fibers of different spans.  
     
     
         27 . A method according to  claim 1 , wherein said at least one network element that is connected to a span having said second number of fibers provides for a connection capability between said fibers and local ports for local data flows at a bit rate lower than the bit rate between the network elements.  
     
     
         28 . A method according to  claim 16 , wherein said second number is higher than said first number.