Con Frame:
<html>
<head>
<title>
</title>
</head>
<frameset rows="80%,20%" border=0 frameborder=no>
<frame src="top.html" noresize, scrolling=no>
<frameset cols="70%,*" border=0 frameborder=no>
<frame src="bottomSx.html" noresize, scrolling=no>
<frame src="bottomDx.html" noresize, scrolling=no>
</frameset>
</frameset>
</html>

Con iframe:
<html>
<head>
<title>
</title>
</head>
<body>
<table border=1 width=100% height=100%>
<tr height=70%>
<td colspan=2>
top</td></tr>
<tr>
<td width=70%>
<iframe src="top.html" name="top" width="100%" height="100%" frameborder="0" scrolling="auto"></iframe>
</td>
<td width=30%>Dx Bottom</td>
</tr></table>
</body>
</html>