Squid QoS with priority to hosts taking little bandwidth

Hello,

I have a quick Squid question. I have a network which has a Squid
proxy in it. I searched over the Internet, looked at Squid FAQ and
Wiki, looked on many forums and still couldn't find the solution to
this problem.

I would like to have users access the Internet through Squid based on
their usage. The more they use the proxy, the less bandwidth they will
be allocated. I tried using delay pools, but I couldn't find any acl
that would support measuring the quantity of data transferred over the
wire. I would like to say something like: OK, you transferred 1 MB,
now you link speed will not be 10KB/s as till now, but will be reduced
to 8KB/s. When you transfer 10 MB, you will be reduced to 7 KB/s. When
you transfer 20 MB, you will be reduced to 5 KB/s. I don't exactly
need such control, but general reduce of the allocated bandwidth to
that user (computer/IP/MAC/whatever other that describes the user).

The intention is that small objects and users that transfer small
amount of data (e.g. just browsing or downloading icons or small
pictures and such) should be given more bandwidth than users
transferring more data (e.g. users downloading DVD ISO images ~4 GB).
Is this possible using Squid? This would stop people from using
different sorts of download accelerators - the more they download (per
second, hour, day, month - whatever possible), the less bandwidth they
will receive and finally they will have download times that are
unacceptable or - better - that are acceptably long so other users
will not notice their limited download rates.

I am using Squid 2.6.

DT