Hi Suhaas,
this dependents on the use case.
If your are only exposing a view component with no view component interface you can simply expose the view component in the interface definition:
<module-interface name="com.sap.wcf.GS.SimpleSearch">
<uiInclude name="SimpleSearch" />
<uiInclude name="SimpleSearchResult" />
</module-interface>
In this case no interface DC is necessary.
But if you offer a view component which expect some input data you need to define the inbound interface:
<module-interface name="com.sap.wcf.GS.AdvancedSearch">
<uiInclude name="AdvancedSearchView"
includeInterface="com.sap.wcf.ui.view.interf.searching.AdvancedSearchInbound" />
</module-interface>
In this example com.sap.wcf.ui.view.interf.searching.AdvancedSearchInbound will be part of an interface DC and for sure all other interface which might be used in the interface itself.
Regards Wolfgang