The Organization Level Access – provides access to common transactions for any user logging on to SAP system in the affected instances. The Security / Basis team owns this layer since the transactions to be put in it are activities that support the general use of the SAP system. Some examples of these activities are access to print, online help, SAP office, etc. This avoids duplicating these same transactions in every job role throughout a landscape. Changes here affect all users, reducing the administrative load for the security team, and speeds up the response time to users. Examples of transactions that would be included at this level are: SU3, SU53, SU56, SP01, etc.
T1- Roles with common access like Spool, ESS etc
T2- Roles with Common transactions across Business
T3- Roles with Transactions according jobs in Business Area
T4- Roles with Job Specific access