Question about networking and topology setup

[Ertza Warraich]

Hi, can I know how the Raw nodes for the cluster Wisconsin d7525 connected? 

I am running some experiments for my academic project which I will be submitting for publication and I need some info on how these nodes are connected. 

Is there a single L2 switch between them, and is that switch shared with any other traffic as well? If I reserve 8 nodes, then the rest of d7525 nodes' which might be in use by someone else then their traffic will also be going through the same switch, right? Can it also experience any other traffic? I am trying to see can there be congestion in that switch and how many tenants/workloads might be using it?

Also, can I know the same for Clemson r7525 nodes as well? 

Thanks.

[Mike Hibler]

I will defer to the Wisconsin and Clemson admins for the final word on
this, but this is my understanding of the switch topologies.

The Wisconsin d7525 nodes are all connected to the same Dell Z9432F
switch. Unfortunately this switch is the core switch for the experiment
network, not only does it have a number of nodes directly connected,
but also is the aggregation point for four other switches and the dataset
storage server. So it is theoretically possible that traffic from all other
experiments could pass through this switch. That said, since the experiment
resource mapping tool favors intraswitch connections whenever possible, most
experiments will have their traffic confined to a single switch, so that
unless they are using multiple nodes types in their experiment or they are
using a remote dataset, their traffic will not traverse the Z9432.

The Clemson r7525 nodes are all connected to a Dell Z9264F switch.
I believe those are the only nodes/switches connected to that switch,
but traffic from other experiments using r7525 nodes will traverse this
switch.

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[Scott Groel]

For Clemson, Mike is correct. All R7525 nodes are connected to a single Dell Z9264 switch. This switch houses the 100G connections for the bluefield-2 adapters, as well as standard 25G Connections. You may have other traffic coming from experiments on other R7525 nodes, but there should be no other traffic traversing this switch. There is an 800Gbit pipe that connects from this Z9264 to our core Z9432 switch that is shared between all R7525 nodes.