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Chapter 15. The Networking Profiles > DUNP AND LAP COMPARED

DUNP AND LAP COMPARED

Because the methods used to access IP-based services in the DUNP and LAP are similar, we assert that a data terminal device that implements both profiles could be developed with little more effort than would be required to implement just one. Moreover, the user experience for both of the profiles on such a device could be quite similar, with applications providing the same user interface and procedures for both the DUNP and the LAP. This is an added benefit to the user, who thus can be concerned with only the task at hand (perhaps browsing or accessing a corporate application), rather than with the underlying method used to connect to the data network.

For either of these two networking profiles, the ultimate objective is to enable a connection between the PPP client function in the data terminal device and a PPP server function residing at the edge of an IP network.[6] The primary difference in the two profiles is the role that the Bluetooth link plays in enabling this connection. Figures Figure 15.4 and Figure15.5 highlight the differences and similarities in supporting IP communications using these two profiles, showing a typical protocol stack used in each. To connect, log in, and authenticate oneself to a PPP service, one may use a dialer application, like those used to connect to an Internet service provider over telephone networks. In the case of the DUNP, a modem connection is required to access the PPP server, and the Bluetooth link replaces a serial cable between the data terminal device and the gateway device that contains the modem service. In the case of the LAP no modems are involved, but the Bluetooth link is used as a substitute for a direct serial connection between the PPP client in the data terminal and the data access point that exports the PPP server function. Apart from this difference regarding the role of the Bluetooth link in the two profiles, the same applications and processes used to achieve IP connectivity with the DUNP can be reused in the LAP.

[6] Note that other protocols besides IP can be multiplexed over PPP. Thus the IP discussion here applies for other protocols, too, but we focus on IP as the most commonly used networking protocol.


  

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