Distributed cache system for optical networks

Abstract

Caching techniques are described. An example network device positioned between an optical line terminal (OLT) and a service provider device includes a hot cache, a wide cache controller, and a control unit. The control unit is configured to receive, from a first service delivery platform, a request for digital content, and determine whether the requested digital content is stored on the hot cache. The control unit is further configured to, when the requested digital content is not stored on the hot cache, determine, using the wide cache controller, whether the requested digital content is stored on a wide cache of a second service delivery platform, receive, from the second service delivery platform, the requested digital content, and responsive to the request received from the first delivery platform, send the received digital content to the first delivery platform.

What is claimed is: 
     
         1 . A method comprising:
 receiving, by a service delivery platform and from a subscriber device communicatively coupled to the service delivery platform, a request that identifies digital content, the service delivery platform being positioned between the subscriber device and a network device such that the service delivery platform is positioned upstream of the subscriber device and downstream of the network device;   responsive to receiving the request, determining, by the service delivery platform, whether the digital content is stored on a wide cache of the service delivery platform and incrementing, by the service delivery platform, an impact rating (IR) of the digital content; and   if the digital content is not stored on the wide cache of the service delivery platform,
 forwarding, by the service delivery platform, the request to the network device; 
 receiving, by the service delivery platform, from the network device, the digital content identified by the request, wherein the digital content comprises received digital content, and wherein the received digital content comprises at least one of 1) digital content stored on a hot cache of the network device, and 2) digital content that is stored on another wide cache of another service delivery platform and that is sent from the another service delivery platform via the network device; 
 forwarding, by the service delivery platform, the received digital content to the subscriber device; and 
 if the incremented IR of the received digital content is greater than a threshold value, storing, by the service delivery platform, the received digital content to the wide cache. 
   
     
     
         2 . The method of  claim 1 , wherein the service delivery platform comprises an optical network unit (ONU). 
     
     
         3 . The method of  claim 1 , wherein the digital content comprises one or both of video data or audio data. 
     
     
         4 . The method of  claim 1 , further comprising:
 if the received digital content is stored on the wide cache, sending, by the service delivery platform, the requested digital content to the subscriber device.   
     
     
         5 . The method of  claim 1 , wherein the digital content comprises first digital content, the method further comprising:
 receiving, by the service delivery platform, from the network device, a backup request that identifies a second digital content;   determining, by the service delivery platform, whether the second digital content is stored on the wide cache; and   if the second digital content is stored on the wide cache, sending, by the service delivery platform, the second digital content to the network device responsive to receiving the backup request from the network device.   
     
     
         6 . The method of  claim 1 , wherein storing the received digital content to the wide cache further comprises:
 selecting, by the service delivery platform, at least one stored item of digital content that is currently stored on the wide cache; and   deleting, by the service delivery platform, the at least one stored item of digital content that was selected from the wide cache.   
     
     
         7 . The method of  claim 6 , wherein selecting the at least one stored item of digital content further comprises:
 selecting, by the service delivery platform, a stored item of digital content from a plurality of stored items of digital content, wherein the stored item of digital content that was selected has a lowest IR of all stored items of the plurality of stored items of digital content.   
     
     
         8 . The method of  claim 1 , further comprising:
 calculating, by the service delivery platform, the IR of the digital content based at least in part on one or more of: 1) a count of all requests for the digital content on a current day, 2) a sum of total hits associated with the digital content within a predetermined time window, 3) a size of all content currently stored on the wide cache, or 4) a factor to differentiate between two or more different types of digital content.   
     
     
         9 . The method of  claim 1 , wherein storing the received digital content to the wide cache further comprises:
 comparing, by the service delivery platform, a size of the received digital content with a size of a competing received digital content, wherein the received digital content and the competing received digital content share an equal IR; and   based at least in part on the comparison, selecting, by the service delivery platform, the received digital content to store to the wide cache.   
     
     
         10 . A service delivery platform being positioned between a subscriber device and a network device such that the service delivery platform is positioned upstream of the subscriber device and downstream of the network device, the service delivery platform comprising:
 a downstream optical network interface;   an upstream optical network interface   a wide cache; and   a control unit configured to:
 receive, via the downstream optical network interface and from a subscriber device communicatively coupled to the service delivery platform, a request that identifies digital content, the service delivery platform being positioned between the subscriber device and a network device such that the service delivery platform is positioned upstream of the subscriber device and downstream of the network device; 
 responsive to receipt of the request, determine whether the digital content is stored on a wide cache of the service delivery platform and increment an impact rating (IR) of the digital content; and 
 if the digital content is not stored on the wide cache of the service delivery platform,
 forward the request to the network device via the upstream optical network interface; 
 receive, via the upstream optical network interface and from the network device, the digital content identified by the request, wherein the digital content comprises received digital content, and wherein the received digital content comprises at least one of 1) digital content stored on a hot cache of the network device, and 2) digital content that is stored on another wide cache of another service delivery platform and that is sent from the another service delivery platform via the network device; 
 forward the received digital content to the subscriber device via the downstream optical network interface; and 
 if the incremented IR of the received digital content is greater than a threshold value, store the received digital content to the wide cache. 
 
   
     
     
         11 . The service delivery platform of  claim 10 , wherein the digital content comprises one or both of video data or audio data. 
     
     
         12 . The service delivery platform of  claim 10 , wherein the control unit is further configured to send the requested digital content to the subscriber device via the downstream optical network interface if the received digital content is stored on the wide cache. 
     
     
         13 . The service delivery platform of  claim 10 , wherein the digital content comprises first digital content, and wherein the control unit is further configured to:
 receive, via the upstream optical network interface and from the network device, a backup request that identifies a second digital content;   determine whether the second digital content is stored on the wide cache; and   if the second digital content is stored on the wide cache, send the second digital content via the upstream optical network interface to the network device, responsive to receipt of the backup request from the network device.   
     
     
         14 . The service delivery platform of  claim 10 , wherein to store the received digital content to the wide cache, the control unit is configured to:
 select at least one stored item of digital content that is currently stored on the wide cache; and   delete the at least one stored item of digital content that was selected from the wide cache.   
     
     
         15 . The service delivery platform of  claim 14 , wherein to select the at least one stored item of digital content, the control unit is configured to:
 select a stored item of digital content from a plurality of stored items of digital content, wherein the stored item of digital content that was selected has a lowest IR of all stored items of the plurality of stored items of digital content.   
     
     
         16 . The service delivery platform of  claim 10 , wherein the control unit is further configured to:
 calculate the IR of the digital content based at least in part on one or more of: 1) a count of all requests for the digital content on a current day, 2) a sum of total hits associated with the digital content within a predetermined time window, 3) a size of all content currently stored on the wide cache, or 4) a factor to differentiate between two or more different types of digital content.   
     
     
         17 . The service delivery platform of  claim 10 , wherein to store the received digital content to the wide cache, the control unit is configured to:
 compare a size of the received digital content with a size of a competing received digital content, wherein the received digital content and the competing received digital content share an equal IR; and   select the received digital content to store to the wide cache based at least in part on the comparison of the size of the received digital content with the size of the competing received digital content.   
     
     
         18 . The service delivery platform of  claim 17 ,
 wherein the control unit is further configured to determine an available storage capacity of the wide cache, and   wherein, to select the received digital content to store to the wide cache based at least in part on the comparison of the size of the received digital content with the size of the competing received digital content, the control unit is configured to determine that the size of the received digital content is less than the available storage capacity.   
     
     
         19 . The service delivery platform of  claim 10 , wherein the service delivery platform comprises an optical network unit (ONU). 
     
     
         20 . A computer-readable storage device comprising instructions that, when executed, cause one or more programmable processors of a service delivery platform to:
 receive, from a subscriber device communicatively coupled to the service delivery platform, a request that identifies digital content, the service delivery platform being positioned between the subscriber device and a network device such that the service delivery platform is positioned upstream of the subscriber device and downstream of the network device;   responsive to receiving the request, determine whether the digital content is stored on a wide cache of the service delivery platform and increment an impact rating (IR) of the digital content; and   if the digital content is not stored on the wide cache of the service delivery platform, forward the request to the network device;
 receive, from the network device, the digital content identified by the request, wherein the digital content comprises received digital content, and wherein the received digital content comprises at least one of 1) digital content stored on a hot cache of the network device, and 2) digital content that is stored on another wide cache of another service delivery platform and that is sent from the another service delivery platform via the network device; 
 forward the received digital content to the subscriber device; and 
 if the incremented IR of the received digital content is greater than a threshold value, store the received digital content to the wide cache.