The best way to understand how Partitions and CSS work is through an example. This example illustrates how a company can restrict call routing for a certain group of users. In this organization we have three types of users. From within the lab environment, only internal calls can be made. Normal employees are not allowed to dial international numbers.
Management can call any number.
These three partitions are used to categorize the possible call destinations. IP phones from Employees will be assigned to CSS 2. IP phones from Management will be assigned to CSS 3. In the figure below we have three IP Phones and one Gateway with two Route Patterns. It is also possible to restrict call routing based on different types of users and location.