[Swift-devel] coaster status summary

[Ioan Raicu]

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!

Here is their email address: ALCF Support <support at alcf.anl.gov>

Cheers,
Ioan

Mihael Hategan wrote:
> On Sat, 2008-04-05 at 08:25 -0500, Ioan Raicu wrote:
>   
>> 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.
>>     
>
> You are describing NAT. I understand what NAT is. I was looking for an
> independent source confirming this.
>
>   
>>  
>>
>> 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:
>>     
>>>> it would matter on a machine such as
>>>> the BG/P, as there is a NAT inbetween the login nodes and the compute nodes.
>>>>     
>>>>         
>>> wierd. is there a description of that somewhere?
>>>
>>>   
>>>       
>
>
>   

-- 
===================================================
Ioan Raicu
Ph.D. Candidate
===================================================
Distributed Systems Laboratory
Computer Science Department
University of Chicago
1100 E. 58th Street, Ryerson Hall
Chicago, IL 60637
===================================================
Email: iraicu at cs.uchicago.edu
Web:   http://www.cs.uchicago.edu/~iraicu
http://dev.globus.org/wiki/Incubator/Falkon
http://dsl-wiki.cs.uchicago.edu/index.php/Main_Page
===================================================
===================================================


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