Fig. 17. SI client-server interaction model.
The special feature of the SI client-server interaction model (Fig. 17) is the ability to use technological addresses defined at any network protocol layer (transport, network, data link or even physical layer) as an address of a data source (client) and destination (server).
SI software components insert these technological addresses into headers of outgoing data packages automatically. These addresses do not contain a technological address of the object requested by the user.
As we can see, this approach completely separates the service stratum managing access to communication services and information resources from the transport stratum managing data transmission.
Fig. 18. SI software components interaction model for a user-to-user session initiation.
To initiate a user-to-user communication session (Fig. 18) a calling user does not need to know the technological address of a called user. In this case, the service stratum is independent from the transport management stratum.
In case of an access to value-added services and information resources, their addresses have clear meaning for a calling user. SI server receives such an address from the software managing an information resource.
Fig. 19. Interaction model for session initiation between the user and an information resource.
A communication between the user and an information resource (Fig. 19) may be a simplex or duplex (interactive) data transmission process. As in the previous case, the user does not know technological (network-specific) addresses of the requested resource. The service stratum is also independent from the underlying transport stratum.
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