🚀 go-pugleaf

In article <32A5C332.56D103BC@shani.net>, YOELK <jkrup@shani.net> writes:
>Yossi Cohen wrote:
>> 
>> ISPs in Europe or Asia pay, as far as I know, about $250K/Year
>> for a T1 line to the U.S. (for the line only, not for the internet
>> connection).
>> 
>> On the other hand, traffic could have been reduced by a significant
>> factor by using a large cache in the proxy http and ftp server. I know
>> 
>> that the academic network in the UK has a cache of 6 machines with
>> 16GB each and they reach 60% hit rate.
>> 
>> It is my guess that by using a huge cache, say 1TB (1000GB), it is
>> possible to get 90% hit rate, i.e. to save 90% of the international
>> lines cost. The cost of 1TB may be about $200k, so it seems a very
>> good investment.
>> 
>> Where am I wrong ?
>> 
>> Does anyone know of some research done in this field of knowing
>> how large should a cache be in order to reach 90% hit rate ?
>> 
>> Thanks,
>> Yossi
>> 
>> ifaa@aquanet.co.il
>
>Proxy would be great for speed up , but it might be good
>for censorship, if it is mandatory.
>
>Beware.
>
>----
>Yoel
>
Now, this can be done also by using some "filtering" of requests. No sweat.
So yes, this is true with caching, but this can be done with other means 
as well

There is another problem: Actuality!

You will always get a copy from the past, NOT the current version, from a chache.
HOW outdated a page is in the chache, depends on it's updating policy, but 
it by definition MUST be outdated.

If you are actually talking to a hidden cache, not the real address, this 
IMHO is a clear case of denial of service. If you're talking to a chache 
(ie proxy server) knowingly, this is ok, but there MUST be a way to 
enforce a direct connection to the real source of information.
(recently I had to do this to get to the current version of an 
phone/address directory after I had found out that the cached version 
gives me a outdated number, just a very simple example)


Apart from this: For MOST stuff, handled in a responsible way, caching 
has real virtues and should be considered in a reasonable and 
responsible way.

Uwe