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<FONT face=Tahoma size=2><B>From:</B>
rdma-developers-admin@lists.sourceforge.net
[mailto:rdma-developers-admin@lists.sourceforge.net] <B>On Behalf Of
</B>Michael Krause<BR><B>Sent:</B> Friday, May 27, 2005 7:25 AM<BR><B>To:</B>
Sukanta ganguly<BR><B>Cc:</B> openib-general@openib.org;
rdma-developers@lists.sourceforge.net<BR><B>Subject:</B> Re: [Rdma-developers]
Re: [openib-general] OpenIB and OpenRDMA: Convergence on common RDMA APIs and
ULPs for Linux<BR></FONT><BR></DIV>
<DIV></DIV><FONT size=3>At 06:40 AM 5/27/2005, Sukanta ganguly wrote:<BR>
<BLOCKQUOTE class=cite cite="" type="cite">Venkata,<BR> How will
that work? If the RNIC offloads RDMA and<BR>TCP completely from the
Operating System and does not<BR>share any state information then the
application<BR>running on the host will never be in the position
to<BR>utilize the socket interface to use the communication<BR>logic to send
and receive data between the remote node<BR>and itself. Some information
needs to be shared. How<BR>much of it and what exactly needs to be shared is
the<BR>question.</FONT></BLOCKQUOTE>
<DIV><BR>Ok. It all depends upon what level of integration / interaction
a TOE and thus a RNIC will have with the host network stack. For
example, if a customer wants to have TCP and IP stats kept for the off-loaded
stack even if it is just being using for RDMA, then there needs to be a method
defined to consolidate these stats back into the host network stack tool
chain. Similarly, if one wants to maintain a single routing table to
manage, etc. on the host, then the RNIC needs to access / update that
information accordingly. One can progress through other aspects of
integration, e.g. connection management, security interactions (e.g. DOS
protection), and so forth. What is exposed again depends upon the level
of integration and how customers want to manage their services. This
problem also exists for IB but most people have not thought about this from a
customer perspective and how to integrate the IB semantics into the way
customers manage their infrastructures, do billing, etc. For some
environments, they simply do not care but if IB is to be used in the
enterprise space, then some thought will be required here since most IT don't
see anything as being "free" or self-managed.<BR><BR>Again, Sockets is an
application API and not how one communicates to a TOE or RDMA component.
The RNIC PI has been proposed as an interface to the RDMA functionality.
The PI supports all of the iWARP and IB v 1.2 verbs.
<BR><BR>Mike<BR><SPAN class=724203916-27052005><FONT face=Arial color=#0000ff
size=2> </FONT></SPAN></DIV>
<DIV><SPAN class=724203916-27052005></SPAN> </DIV></BLOCKQUOTE>
<DIV dir=ltr><SPAN class=724203916-27052005>I'd like to add that RNIC-PI is
planning on explicitly defining some of these "obvious"
dependencies </SPAN></DIV>
<DIV dir=ltr><SPAN class=724203916-27052005>between the RDMA stack and the
primary IP stack. For example, the RDMA stack cannot maintain</SPAN></DIV>
<DIV dir=ltr><SPAN class=724203916-27052005>any connection in a state that
contradicts current IP stack routing. It has to adapt or break the
connection.</SPAN></DIV>
<DIV dir=ltr><SPAN class=724203916-27052005>We can't have an RNIC that has its
own ARP table that is not in sync with the host's ARP table.</SPAN></DIV>
<DIV dir=ltr><SPAN class=724203916-27052005></SPAN> </DIV>
<DIV dir=ltr><SPAN class=724203916-27052005><FONT face=Arial color=#0000ff
size=2>An iWarp RDMA stack gains the benefit of many pre-existing network
services (such as DNS, ARP</FONT></SPAN></DIV>
<DIV dir=ltr><SPAN class=724203916-27052005><FONT face=Arial color=#0000ff
size=2>and routing). But that also carries with it the need to not contradict
those exisiting services. So it is</FONT></SPAN></DIV>
<DIV dir=ltr><SPAN class=724203916-27052005><FONT face=Arial color=#0000ff
size=2>both a benefit and a restriction -- and a major divergence from an IB
RDMA stack.</FONT></SPAN></DIV>
<DIV dir=ltr><SPAN class=724203916-27052005></SPAN> </DIV>
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