Chapter 6 -- Remote Access Service API

Chapter 6

Back in the old daysaround 1988I was working on a 16-bit MS-DOS application that required a consolidation of billing information from dozens of remote sites into a central location on a nightly basis. The sites were separated by hundreds of miles, many in locations so remote that physical transportation of diskettes to the central site was impractical . Furthermore, this happened long before the ubiquitous Internet and freely available e-mail. The solution back then was a polling program that called each remote site on a nightly basis and used a custom program to handle the Xmodem protocol required for binary file transfers.

Today things would be very different. While much of what I did could be handled in essentially the same way, using the Telephony API (TAPI) discussed in the next chapter, or using e-mail via the Messaging API (MAPI), which is also discussed in the next chapter, there is also a third way. Remote Access Service (RAS) allows two computers to be connected using standard phone lines. The connection does not result in a special-purpose link between the two machines, but rather in an extended wide area network (WAN). With this WAN established, all of the APIs that work on a local area network (LAN) are available, giving you the ability to simply copy files from one machine to another, though admittedly at a slower rate than a LAN connection. This ability to establish extended WAN connections allows a single code base to be used for both LAN-attached and remote sites. This flexibility allows seamless scalability from multiple remote sites, hooked only by phone wires, to massive WANs crossing the country or the globe.

The client side of RASwhere your computer dials into a server that is waiting to accept such connectionsis employed whenever a user makes a phone connection to the Internet. The server can be a Microsoft Windows 2000 server or any server that can provide a connection understood by RAS, such as the commonly used Point-to-Point Protocol (PPP) or Serial Line Internet Protocol (SLIP).

Like many aspects of Windows development, the naming of components related to this technology has not helped foster a coherent image for RAS, especially in how the names differ between what the developer sees and what the Windows 2000 user sees. On my Windows NT 4 server, the RAS client is accessed through the Accessories menu as Dial-Up Networking. In Windows 2000, the feature previously known as Dial-Up Networking is available on the Settings menu (and in Control Panel) as Network And Dial-Up Connections. Thus, even if you are a programmer who regularly uses RAS to connect to remote sites or to the Internet, you might not be aware of RAS under the new name .



Inside Server-Based Applications
Inside Server-Based Applications (DV-MPS General)
ISBN: 1572318171
EAN: 2147483647
Year: 1999
Pages: 91

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