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If you won't take my word for it, when I have been on the machine and
have seen what I described first hand, then feel free to write tech
support for the BG/P!<br>
<br>
Here is their email address: ALCF Support <a class="moz-txt-link-rfc2396E" href="mailto:support@alcf.anl.gov"><support@alcf.anl.gov></a><br>
<br>
Cheers,<br>
Ioan<br>
<br>
Mihael Hategan wrote:
<blockquote cite="mid:1207473251.10063.1.camel@blabla.mcs.anl.gov"
type="cite">
<pre wrap="">On Sat, 2008-04-05 at 08:25 -0500, Ioan Raicu wrote:
</pre>
<blockquote type="cite">
<pre wrap="">I looked around for some docs on the networking structure, but couldn't
find anything.
There are several networks available on the BG/P: Torus, Tree, Barrier,
RAS, 10Gig Ethernet.
Of all these, we are only using the Ethernet network, which allows us to
communicate via TCP/IP (or potentially UDP/IP) between compute nodes and
I/O nodes, or between compute nodes and login nodes. For the rest of
the discussion, we assume only Ethernet communication. There is 1 I/O
node per 64 compute nodes (what we call a P-SET), and the I/O node can
only communicate with compute nodes that it manages within the same
P-SET (the 64 nodes). A compute node from one P-SET cannot directly
communicate with another compute from a different P-SET. This is
primarily because compute nodes have private addresses (192.168.x.x),
I/O nodes are the NAT between the public IP and the private IP, and the
login nodes only have a public IP. So, the compute nodes all have the
same IP addresses, 192.168.x.x, and they repeat for every P-SET, and the
I/O nodes handle their traffic in and out.
</pre>
</blockquote>
<pre wrap=""><!---->
You are describing NAT. I understand what NAT is. I was looking for an
independent source confirming this.
</pre>
<blockquote type="cite">
<pre wrap="">
Zhao, if you have any docs on the Ethernet network and the NAT that sits
on the I/O node, can you please send it to the mailing list?
Ioan
Ben Clifford wrote:
</pre>
<blockquote type="cite">
<blockquote type="cite">
<pre wrap="">it would matter on a machine such as
the BG/P, as there is a NAT inbetween the login nodes and the compute nodes.
</pre>
</blockquote>
<pre wrap="">wierd. is there a description of that somewhere?
</pre>
</blockquote>
</blockquote>
<pre wrap=""><!---->
</pre>
</blockquote>
<br>
<pre class="moz-signature" cols="72">--
===================================================
Ioan Raicu
Ph.D. Candidate
===================================================
Distributed Systems Laboratory
Computer Science Department
University of Chicago
1100 E. 58th Street, Ryerson Hall
Chicago, IL 60637
===================================================
Email: <a class="moz-txt-link-abbreviated" href="mailto:iraicu@cs.uchicago.edu">iraicu@cs.uchicago.edu</a>
Web: <a class="moz-txt-link-freetext" href="http://www.cs.uchicago.edu/~iraicu">http://www.cs.uchicago.edu/~iraicu</a>
<a class="moz-txt-link-freetext" href="http://dev.globus.org/wiki/Incubator/Falkon">http://dev.globus.org/wiki/Incubator/Falkon</a>
<a class="moz-txt-link-freetext" href="http://dsl-wiki.cs.uchicago.edu/index.php/Main_Page">http://dsl-wiki.cs.uchicago.edu/index.php/Main_Page</a>
===================================================
===================================================
</pre>
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