Hi,
By default, each app runs in its own sandbox. When an app is constructed, all the IPC services it needs are declared. At runtime, the Supervisor and the Service Directory enforce that only those approved IPC services are accessed by the app. Approval is specified through “bindings”.
Binding is between Client and Server. CLient -Server can be 2 applications or 2 components in application which are 2 different process. This dictates the need for bindings.
Check this link (Application Definition .adef - Legato Docs) for various syntax and conditions to use them
We don’t recommend circular dependency to avoid deadlocks.
You can check this link for more information http://legato.io/legato-docs/latest/basicIPC.html
Regards,
Vasantha