In this way, load balancing between different networks can be achieved. You must include one line for each of your neighbors. Use a value of 0 if your neighbor does not run ICP, or 7 if your neighbor runs the UDP echo service. This can help Squid to detect if the host is alive. You can specify the option default to use this host as a last resort in case you can't speak ICP with your parent cache.
Larger values give higher weights.
If you have a stand-alone cache, you should not include any of these directives. If you have only one parent cache, the overhead of the ICP protocol is unnecessary. Also, there are some domains you will always want to fetch directly rather than from your neighbors. Your own domain is a good example. Fetching objects belonging to your local web servers from a faraway cache is not efficient.