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Re: What can you cache? [was: Byte ranges -- formal spec proposal ]

From: <Harald.T.Alvestrand@uninett.no>
Date: Mon, 22 May 1995 12:43:21 +0200
Message-Id: <199505221043.MAA08223@dale.uninett.no>
To: David - Morris <dwm@shell.portal.com>
Cc: http working group <http-wg%cuckoo.hpl.hp.com@hplb.hpl.hp.com>
Dave Morris writes:
> Surely, skew in relative seconds is preferable to guaranteed skew
> in interprestation of an absolute time based on local system
> clock.
> 
> Practically, system clocks can be skewed by minutes or more. Relative
> time skew is more likely to vary by seconds.  At least if the
> proxy adjusts the cache time remaining when providing a relative
> cache expires limit to a requestor (UA or cascaded proxy same
> issue)
> 
> Dave Morris 
IMHO, any node on the Internet that does not run some sort of network
time protocol is mismanaged, and does not deserve consideration when
writing protocol specifications.
(My laptop uses "netdate" everytime I insert an Ethernet card...we
don't need to run NTP on *every* host)

On the other hand, it is most certain that in the current always-overloaded
Internet, there is non-negligible delay between servers, and the server
has no way of calculating the delay in transfer of a query or a response
when "adjusting the relative timeout".

Let's use absolute time.

            Harald A
Received on Monday, 22 May 1995 03:45:22 EDT

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