We discuss the remaining three major modules in the HyperProxy design. Active prefetching helps with every subsequent access to a media object. It helps determine when to prefetch which segment.
In the case when no segment is cached, the prefetching of the Bs/Bt segment is considered.The new segment admission is marked with priority
If there are a few segments cached that number less than the Bs/Bt threshold, then the proxy jitter is unavoidable. The new segment admission is marked with priority.
IF there are more segments cached than the said threshold, the prefetching of the next segment starts at an offset Bs/Bt number of segments from this candidate. The new segment admission is marked with non-priority.
Bs is the encoding rate of the segment and Bt is the network bandwidth of the proxy server link.
Active prefetching of exponentially segmented object.
Next we consider the lazy segmentation strategy. When there is no cache space available and replacement is needed, the replacement policy kicks in and calculates the caching utility of each cached object. The smallest utility value items are evicted first.  If the object is fully cached, the object is segmented uniformly based on the average access duration at the time. Then a certain number of segments are retained and the rest are evicted.
The replacement policy uses a formula to determine the utility value and the eviction is based on the maintenance of two lists - the basic list and the priority list