Hi,
ad 1) my network range is 152.6.0.0 255.255.0.0)do i need to define it within this range?
Yes, you should define the loopback address within your address range.
The loopback interface purpose is the fact it's always up. So it's available for the management purposes in the case physical interface(s) went down (as long as there is a route path to the loopback).
ad 2) can i define ine ip address to all routers on their loopback interface?
My understanding is the question was:
Can i define ONE ip address to all routers on their loopback interface?
No, each loopback interface has to have a unique IP address.
Regards,
Milan
