Re: cache not up to date

From: Thomas Schmidt <>
Date: Thu, 27 Jun 1996 23:00:09 +0200

>Jean-Francois Micouleau <> wrote:
>> That's how squid handle IMS. IMS handling is now perfect by now,
>> in squid 1.1 it sould be better.
>I agree. The current IMS support are a tradeoff between functionality
>and implementation time. It is better than nothing, but far from the
>best possible implementation...
>> Henrik could you please explain what you plan for IMS ?
>Any comments are welcome. I will begin work on this in a few days.

Some weeks ago I posted a proposal how to handle IMS:

1 From requestor to page source through the cache hierarchy each cache
has to check, if it owns a modified version:
1.1 No, our page isn't more recent or we've no such page. Forward query
to next cache.
1.2 Yes, we've a modified page. Ask next cache in hierarchy, if it has a
more recent page than ours.

2. At last the request arrives the pages owner. It should also look for
modification. If its page is
2.2 not modified against the requests date it should return NOT-MODIFIED.
2.1 modified it should return this page.

3. From page source to requestor. If a cache
3.1 gets a full page it should forward it.
3.2 gets a NOT-MODIFIED it should
3.2.1 return this answer if check 1.1 applied
3.2.2 return its page if check 1.2 applied.

At last the requestor gets the most recent version of this page from the
closest possible site.

OK ?


|Thomas Schmidt    | Email: | Phone: +49-30-7829537|
|Leuthener Str. 4a |[Email:]    | Fax: +49-30-7828103  |
|D-10829 Berlin    |                                | Data: +49-30-7828103 |
Received on Thu Jun 27 1996 - 14:02:30 MDT

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