[Swift-devel] coaster status summary

[Mihael Hategan]

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?
> >
> >   
>