- From: David W. Morris <dwm@shell.portal.com>
- Date: Wed, 3 Jan 1996 13:58:29 -0800 (PST)
- To: HTTP Caching Subgroup <http-caching@pa.dec.com>
On Wed, 3 Jan 1996, Daniel W. Connolly wrote: > > What exactly is the test for freshness using deltas, and what are the > input parameters? Does the number of parameters increase with the First I must assume reasonable local integrity of the server's clock. Then, when a delta expiration arrives, an actual expiration is computed (and probably stored as an epoc time suitable to the server). This expiration now is tested just as a parsed and stored absolute time. When a cached entity is served, a new delta expiration is computed and provided in the response header. > themselves). The second caching proxy requests this resource at > 1:15. Does the first proxy re-write the Cache: header? Yuk. What > about latency? I don't believe re-writing the header is a big deal. Caching related header data is going to be processed and manipulated in any event. Latency is a much smaller issue than out of sync clocks. Latency will generally be in the rage of seconds (assume first byte in is approx sent time + minimum latency) while system clocks are easily minutes off. I assert that any document which won't still be servable over an interval >> latency shouldn't be marked cachable in the first place. Again, this problem is samller than clock differences and hence the result will more closely reflect what is desired by the information providers. Dave Morris
Received on Wednesday, 3 January 1996 22:13:56 UTC