In the following scenario, we will check whether or not a client (C) can use an object (S) of a provider package (server). The user and provider packages are stored in different structure packages. For example, the provider could be part of the R/3 Enterprise Core, in the structure package ABA, while the user could be part of the Core Extension. Core Extensions include Add-Ons (delivered by SAP), partner developments, and customer developments.
To see exactly how the package check is performed in this case, see the
How the Package Check Works.