Hierarchical caching for online media

A first cache device comprising:

• a processing unit including a processor,
• the first cache device being programmed to perform, with the processor, operations including,
• receiving, at the first cache device, a request to send a first asset to a second device;
• determining whether the first asset is stored at the first cache device;
• when the determining whether the first asset is stored at the first cache device indicates that first asset is not stored at the first cache device,
• obtaining, at the first cache device, the first asset,
• performing a comparison operation based on an average inter-arrival time of the first asset with respect to the first cache device and a characteristic time of the first cache device,
• the characteristic time of the first cache device being an average period of time between receipt of last requests for, and eviction of, assets cached at the first cache device, and
• determining whether or not to cache the obtained first asset at the first cache device based on the comparison;
• and
• sending the obtained first asset to the second device.

A method of operating a content distribution network, the content distribution network including a plurality of first cache devices, the plurality of first cache devices being divided into a plurality of hierarchy levels, the method comprising:

• performing a first caching operation for each of the plurality of first cache devices, respectively, such that, for each one of the plurality of first caching devices divided into the plurality of hierarchy levels, the first caching operation includes,
• receiving, at the first cache device, a request to send a first asset to a second device;
• determining whether the first asset is stored at the first cache device;
• when the determining whether the first asset is stored at the first cache device indicates that first asset is not stored at the first cache device,
• obtaining, at the first cache device, the first asset,
• performing a comparison operation based on an average inter-arrival time of the first asset with respect to the first cache device and a characteristic time of the first cache device,
• the characteristic time of the first cache device being an average period of time between receipt of last requests for, and eviction of, assets cached at the first cache device, and
• determining whether or not to cache the obtained first asset at the first cache device based on the comparison;
• and
• sending the obtained first asset to the second device.

A content distribution system comprising:

• a plurality of first cache devices,
• the plurality of first cache devices being divided into a plurality of hierarchy levels,
• each of the plurality of first caches devices being programmed to perform a first caching operation, respectively, such that, for each one of the plurality of first caching devices, the first caching operation includes,
• receiving, at the first cache device, a request to send a first asset to a second device;
• determining whether the first asset is stored at the first cache device;
• when the determining whether the first asset is stored at the first cache device indicates that first asset is not stored at the first cache device,
• obtaining, at the first cache device, the first asset,
• performing a comparison operation based on an average inter-arrival time of the first asset with respect to the first cache device and a characteristic time of the first cache device,
• the characteristic time of the first cache device being an average period of time between receipt of last requests for, and eviction of, assets cached at the first cache device, and
• determining whether or not to cache the obtained first asset at the first cache device based on the comparison;
• and
• sending the obtained first asset to the second device.