In this section, we present data to demonstrate the benefits of shared caches and study the properties of the CRISP architecture, using four traces of Internet access from different user communities. Our two largest traces are taken from the access logs from a centralized proxy cache used by thousands of the AT&T technical community, and a 24-hour subset (Aug. 29, 1996) of the publicly available proxy traces from Digital Equipment Corporation [8]. These traces are labeled AT&T and DEC in the figures, and represent accesses from 3806 and 3636 clients respectively. The Medium trace was taken from a proxy used by 218 researchers from one AT&T Bell Labs center. The fourth workload, Small, was taken from a pilot CRISP cache used by a group of 23 volunteers. The trace periods range from 24 hours for the largest traces to several days for the Small trace.