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7<TITLE>Packet Flow when Using WBT</TITLE>
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11<H1 align="left">Packet Flow when Using WBT</H1>
12<H2>Description</H2>
13<P>
14The figure below shows the packet flow during download and upload when using WBT.<BR> <FONT color="red"><B>Note: Since half-duplex communications are used between parents and children, if an upload and download occur at the same time, the upload takes priority from the child's perspective.</B></FONT><BR>
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17<P><B>Packet flow during download</B></P>
18<P>
19The following figure shows the packet flow exchanged between parent and child during download.
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21<BLOCKQUOTE><IMG src="image_WBT_Download.GIF" border="0"></BLOCKQUOTE>
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24<P><B>Packet flow during upload</B></P>
25<P>
26An upload is essentially the same as a download, but the parent and child actions are reversed. For an upload, the child must notify the parent by sending block information using <CODE>WBT_PutUserData</CODE>. (If the upload occurs immediately after <CODE>RequestSync</CODE> and the blocks to upload will not change, the <a href="../command/WBT_GetBlockInfo.html"><CODE>WBT_GetBlockInfo</CODE></a> function may be called as the <CODE>RequestSync</CODE> receive callback.)<BR><BR> The following figure shows the packet flow exchanged between parent and child during upload.<BR>
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28<BLOCKQUOTE><IMG src="image_WBT_Upload.GIF" border="0"></BLOCKQUOTE>
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30<H2>See Also</H2>
31<P><CODE><A href="../list_wbt.html">WBT Function List</A><BR></CODE></P>
32<H2>Revision History</H2>
33<P>
342006/03/13 Initial version.</P>
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