Figure 1 - Download the logical structure of the service system
The content server is an entity that provides MIME content for mobile users. The download server receives the download request from the terminal and manages the transfer from the content server to the terminal browser. Content servers use WAP PUSH Business Load (Service Loading) trigger content download. The functions available to download the server are as follows: Device storage capability management Download Management content asynchronous delivery support for downloading services include ringtone downloads, photo download, screensaver download, short video download, etc. In addition, the download service has a standard OTA download server feature that can be used for download servers for the Java / Brew system. A typical download process is divided into MS-initiated downloads and downloaded by the network. The downloads initiated by the network are as follows: 1) Content Server uses WAP PAP protocol [WAP PAP] to PUSH Proxy for mobile users ( WAP Gateway) Sends a WAP PUSH SL [WAP SL] message. When the phone receives the SL notification message, there is a user's interrupt indication in the SL content type. In the PUSH SL message, the download application (DF Server Application) URL is indicated, and please refer to Section 4. 2) PUSH Proxy parses the MS address to complete some access control check (if required), then pass the PUSH SL content type to the MS browser (the X-WAP-Application-ID header indicates the WML User Agent). 3) The WML user browser performs SL content and establishes a connection with Pull Proxy to download the MMC document indicated in the SL content type. 4) MS should use the preset DF Server URL instead of Proxy: Download. In this event, if the DF Server address is not set, MS receives a message containing Proxy: Download, the MS browser should display an error message; the WML user browser performs WSP GET operations for the specified SL content type URL, Pull Proxy resolution This URL is also sent to the DF Server application. 5) In the GET response message, the DF Server constructs and transmits the MMC document containing the OPEN operation (indicating the MS browser to establish MMC session) and the READ operation (determined the currently available storage amount). The SATUS-URI attribute of the MMC document (see Section 5) is the resource related to DF Server. 6) DF Agent performs POST operations on the MMC status document according to the previous request. This document contains the session ID of the MMC-ID property (generated by DF Agent) and a valid storage amount in bytes. The MMC document issued by DF Server is a session that is identified by the MMC-ID property. 7) DF Server compares the size of the object to be downloaded and the mobile phone storage values. If the payment of the mobile phone is less than the download object, send the "Out of Memory" Status message to the content server (refer to Section 4.3), and send a disconnect operation to the DF Agent. Skip Step 8-12.8) If the phone has sufficient storage, the DF Server constructs and transmits the MMC document that contains Write and CommIT operations. However, the downloaded object will not be submitted to the permanent storage of the phone unless it has been successfully downloaded (refer to 5.2.4). Download status messages as the value of the Display.Message parameter is also included in the MMC document. The Status-URI attribute in the MMC document (see Section 5) is the resource related to DF Server. 9) DF Agent downloads the FUN object from the URL in the MMC document. 10) DF Agent Reports the MMC Operating Status to the DF Server.
