Hello,
i have a squid box with 1 interface with theses configuration

ip:66.66.66.66
gateway:66.66.66.1 (my mikrotik)
dns: 66.66.66.1 (my mikrotik)

in same time this squid box is a parent proxy to my mikrotik web_proxy
parent: 66.66.66.66:808

all i want to do is that my client take all cached content from my squid unlimited because not everything reply it from squid to my mikrotik_proxy is stored in cache and analysed as TOS so puting cache hits from mikrotik unlimited not doing the job if the files not stored in the hdd.
best regards

Have squid apply a known DSCP value to the packets, mark those packets accordingly and exclude them from any QoS you're doing (or QoS them at a high priority with a high speed).

the squid has no limit from and to my mikrotik but the clients have limits so when i remove the limits from one of my customers he can get unlimited traffic from the squid cache. so what i need is to keep the clients limited but only marque the paquet going from my squid throw my mikrotik to my clients in unlimited mode.
best regards

it depends on the way you are limiting your clients

with simple qeue without any mangle or paquet marks.