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<TITLE>RE: [openib-general] ip over ib throughtput</TITLE>
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<P><FONT SIZE=2>Note however that the relevant IB limit is the max ***message size*** which happens to be equal to the ***IB*** MTU for the current IPoIB (that runs on top of IB UD transport service where IB messages are limited to a single packet).</FONT></P>
<P><FONT SIZE=2>A connected mode IPoIB (that runs on top of IB RC/UC transport service) would allow IB messages up to 2GB long. That will allow for much larger (effectively as large as you may ever dream of) ***IP*** MTUs, regardless of the underlying IB MTU.</FONT></P>
<P><FONT SIZE=2>Diego</FONT>
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<P><FONT SIZE=2>> -----Original Message-----</FONT>
<BR><FONT SIZE=2>> From: Hal Rosenstock [<A HREF="mailto:halr@voltaire.com">mailto:halr@voltaire.com</A>] </FONT>
<BR><FONT SIZE=2>> Sent: Wednesday, January 05, 2005 2:21 PM</FONT>
<BR><FONT SIZE=2>> To: Peter Buckingham</FONT>
<BR><FONT SIZE=2>> Cc: openib-general@openib.org</FONT>
<BR><FONT SIZE=2>> Subject: Re: [openib-general] ip over ib throughtput</FONT>
<BR><FONT SIZE=2>> </FONT>
<BR><FONT SIZE=2>> </FONT>
<BR><FONT SIZE=2>> On Wed, 2005-01-05 at 12:23, Peter Buckingham wrote:</FONT>
<BR><FONT SIZE=2>> > stupid question: why are we limited to a 2K MTU for IPoIB?</FONT>
<BR><FONT SIZE=2>> </FONT>
<BR><FONT SIZE=2>> The IB max MTU is 4K. The current HCAs support a max MTU of 2K.</FONT>
<BR><FONT SIZE=2>> </FONT>
<BR><FONT SIZE=2>> -- Hal</FONT>
<BR><FONT SIZE=2>> </FONT>
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