For the current Apache VCL release (version 2.2.1), the system requires a minimum of two parallel networks, i.e.:
(1) A private network, providing interconnectivity between the VCL management node and the deployed target server(s) (the latter with the requested software being provided to the end user, running either real or virtual images). This private network allows the management node to manage the pool of server resources, and to load and tear down the images (OS plus applications/middleware) on the target server(s) that will be handed to an end user.
(2) A public network, providing outside users access to the main VCL GUI via the internet, to request hardware/software resources, and to then connect them directly to the allocated server(s).
This is enabled by installing two Ethernet NICs per target server, with a minimum bandwidth of 1 Gbs each.
For additional details, see https://cwiki.apache.org/confluence/display/VCL/Network+Layout
Note from above that under some possible operational modes, only one NIC is required (e.g., when accessing the IBM Smart Cloud). Under other circumstances (e.g., controlling blades) more than two NICs may be recommended.