Networks created within the openstack platforms are not routed trough NTNU, thus in theory it is not important which subnet is selected. It might however be a problem if your virtual machine needs to contact external resources and you have provision your virtual machines within the same address range that is currently being use elsewhere, causing your local address range to overlap with the address range of another network. Because Because of this, it is common practice to use the address ranges specified in the RFC1918 (a.k.a IPv4 Private Address Space):
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