Re: 13.1.2 Warnings
Koen Holtman (koen@win.tue.nl)
Fri, 18 Oct 1996 00:28:20 +0200 (MET DST)
Ben Laurie:
>Jeffrey Mogul wrote:
>>
>> You've made a convincing case that the existing design for Warning
>> can yield bogus Warnings when HTTP/1.0 and HTTP/1.1 caches are
>> combined. (I believe we wrote the HTTP/1.1 caching rules so that
>> an HTTP/1.1 cache in the position of your cache "B" would remove
>> the Warning after doing a successful validation from cache "A",
>> but of course it's too late to apply that to the HTTP/1.0 caches
>> out there.)
>>
>> So please suggest a solution!
>>
>> I can see three options:
>> (1) Live with it. This can only happen when an HTTP/1.0
>> cache is a client of an HTTP/1.1 cache, and presumably
>> in somewhat unusual cases, so maybe it's a temporary
>> problem.
>
>Something you'd have to live with for a long time, I suspect. Not an
>acceptable option, IMHO.
I think (1) is the most acceptable solution of the three. At some
time, we need to add a note to the spec telling that 1.1 clients
should be aware that 1.0 caches could send erroneous staleness related
Warnings. The note should outline a method to deal with this.
It is not very bad if that method causes a few cache misses. Even if
chains with 1.0 caches in them will become common, responses with
Warnings won't, so the impact on overall efficiency should be small.
Koen.