[PVE-User] Cluster network via directly connected interfaces?

[Frank Thommen]

Please excuse, if this is too basic, but after reading 
https://pve.proxmox.com/wiki/Cluster_Manager I wondered, if the 
cluster/corosync network could be built by directly connected network 
interfaces.  I.e not like this:

  +-------+
  | pve01 |----------+
  +-------+          |
                     |
  +-------+     +----------------+
  | pve02 |-----| network switch |
  +-------+     +----------------+
                     |
  +-------+          |
  | pve03 |----------+
  +-------+


but like this:

  +-------+
  | pve01 |---+
  +-------+   |
      |       |
  +-------+   |
  | pve02 |   |
  +-------+   |
      |       |
  +-------+   |
  | pve03 |---+
  +-------+

(all connections 1Gbit, there are currently not plans to extend over 
three nodes)

I can't see any drawback in that solution.  It would remove one layer of 
hardware dependency and potential spof (the switch).  If we don't trust 
the interfaces, we might be able to configure a second network with the 
three remaining interfaces.

Is such a "direct-connection" topology feasible?  Recommended? Strictly 
not recommended?

I am currently just planning and thinking and there is no cluster (or 
even a PROXMOX server) in place.

Cheers
frank