LimitRange and ResourceQuota are both applied at namespace level - means a constraint in namespace A does not work in a namespace B.

The difference is that LimitRange is a constraint for individual (descrete) Containers and Pods of this namespace.

In contrast ResourceQuota is a constraint for the sum of all kinds of objects of the same namespace - a Pod is one kind of an object. Means the ResourceQuota for CPU is a constraint for all the Pods together within this namespace.