Whole block

It is the modularized layer structure which made the four following things one unit.
At present, it has only a module relevant to "SIP."
In the future, other things are due to be added.


B2BUA Layer

This layer defines a sequence required as operation of UA.
and it has responsibility about two or more transactions and dialogs.

UA Layer

This layer implements the function in the single functional unit.
It exists as a module (API) for B2BUA Layer to use it.

Stack Layer

This layer has responsibility to processing of a transaction level.

Transport Layer

This layer treats processing of the Socket level which adopted MINA.