Architecture

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This chapter offers a general description of Wireless Data Server's architecture, including its interactions with the calendar server and possible setups for connecting to the wireless network.

• Connecting to the calendar server
• Using an alternate content source
• Connecting to the wireless network

Wireless Data Server is an intermediary between the calendar server or other content server on one hand and the mobile network on the other. Wireless Data Server's calendar service translates and transmits data bi-directionally, "pulling" desired information from the calendar database, and "pushing" configurable reminders and notifications to the phone. It consists of three components: the server core, the smsnotify utility, and a plug-in for connecting to the Short Message Service Center (SMSC).

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Connecting to the calendar server

This section describes the two kinds of possible interactions between Wireless Data Server and calendar server: those that occur when a message originating from the mobile phone is sent through Wireless Data Server to the calendar server, and those that occur when a reminder or notification is sent from the calendar server through Wireless Data Server to the mobile phone.

Mobile-originated messages

When you start Wireless Data Server, it establishes a persistent connection to each node of each calendar server specified in wds.ini. It logs in as SYSOP for all nodes, using the encrypted passwords you set in wds.ini. See Chapter 2, "The calendar service," for details on setting up connections with the calendar server.

When Wireless Data Server receives a short message from the wireless network, it interprets the message and translates it into a syntax understood by the calendar server. Wireless Data Server then passes the request on to the calendar server, identifying the sender by the MSISDN of his or her phone. The calendar server handles it the same way as it handles a request from any other client connection. For more information, please see your calendar server's Administrator's Guide.

NOTE:

Because the requesting user is identified by the MSISDN of his or her phone when making requests through Wireless Data Server, each user must have a unique MSISDN set on the calendar server.

Mobile-terminated messages

When the calendar server sends a reminder or notification to a wireless device through Wireless Data Server, it follows a process similar to that for e-mail notifications, calling an external application for delivery of the calendar information. For wireless reminders and notification, the calendar server calls the smsnotify utility from the /users/unison/bin directory. This program passes the calendar information via SMTP to Wireless Data Server. Wireless Data Server then reformats the information and sends it by SMS over the wireless network to the mobile phone.

The model of Wireless Data Server's connection to the calendar server can be summarized as follows:

Figure 1.1 · WDS / calendar server interactions

For detailed configuration information, see Chapter 2, "The calendar service."

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Using an alternate content source

Wireless Data Server can push potentially any kind of information to users. For example, a subscription service could use Wireless Data Server to provide users with stock quotes, sports scores or horoscopes over the wireless network. When using alternate content sources, Wireless Data Server can only send information one way, from the content server to the user; calendar requests are the only mobile-originated messages that Wireless Data Server can process.

To use an alternate content source, you must send data to Wireless Data Server as plain text or Extensible Markup Language (XML) over SMTP. Certain information must also accompany this message, identifying the intended recipient and the type of data sent. For more details, see Chapter 3, "Using another content service."

Figure 1.2 · Sending other content through Wireless Data Server

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Connecting to the wireless network

Wireless Data Server can use either of two methods of connecting to the wireless network. For detailed configuration information, see Chapter 4, "Connecting to the wireless network."

Data Circuit-terminating Equipment (DCE)

Wireless Data Server can connect to the wireless network through a modem, using the Data Circuit-terminating Equipment (DCE) plug-in. This plug-in is provided along with the Wireless Data Server core. The modem and Short Message Service Center (SMSC) communicate over the wireless network.

Figure 1.3 · DCE installation

Short Message Peer to Peer (SMPP)

In this implementation, Wireless Data Server connects directly to the SMSC using the Short Message Peer to Peer (SMPP) protocol, through its SMPP plug-in.

Figure 1.4 · SMPP installation

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