today we continue our discussion on the design of streaming proxy. we were calculating the number of segments for continuous delivery. We were considering both th uniformly segmented media and the exponentially segmented media. We now review the tradeoff between the low proxy jitter and the high byte ratio and then the byte hit ratio versus the delayed startup ratio.In theory, we know the minimum number of segments that must always be cached in the proxy to guarantee a proxy jitter free delivery. In practice, this is difficult for each and every media object because cache size is limited. One way to overcome this is to determine if a media object is popular.  Popular objects are always cached to reduce network traffic and server load. If an object is popular enough all its segments can be cached in the proxy even larger than the prefetching length. On the other hand, if the objects are not popular enough, some segments may get evicted and only a few of it's segments cached. This can contribute to proxy jitter. Given a higher priority in reducing the proxy jitter, the proxy can choose to evict segments of the object whose cached data length is larger than its prefetching length so that the prefetching of its uncached segments can always be in time. If the popular objects get evicted by any chance, this would contribute to the byte hit ratio. Thus we can simulate the availability of all segments for media objects that are popular.