Zend certified PHP/Magento developer

how to correctly configure squid delay pool

This is my squid.conf

delay_pools 1
delay_class 1 1
delay_access 1 allow localnet
delay_parameters 1 -1/-1 -1/-1
delay_access 1 deny all

I have a single local network and I want a single pool and my total bandwidth is 15 Mbit/s. What I want is that if any user consumes this bandwidth, bandwidth drops to 5 Mbit/s.
How I do this?

I know I need to modify this parameter. example:

delay_parameters 1 -1/-1 131072/1048576

But I don’t know what are the values that I should put (I don’t have a table of values to calculate the bandwidth for squid. If someone provides it I will be grateful)