The MTV migration doc mentions using "Migration Network" here [1]. However, it doesn't tell which migration network is supported and will work from the additional network options available in OpenShift [2]. For example, a bridge network will not work for MTV because it is meant for communication between pods.  Also, there is a high probability that the users might use cnv-bridge for this purpose which also won't work. 

I think the documentation should be having instructions on how to configure the migration network (or at least links to the OpenShift doc that says how to configure the same) and the supported/tested network that can be used for this. 

[1]https://access.redhat.com/documentation/en-us/migration_toolkit_for_virtualization/2.4/html-single/installing_and_using_the_migration_toolkit_for_virtualization/index#selecting-migration-network-for-vmware-source-provider_mtv, https://access.redhat.com/documentation/en-us/migration_toolkit_for_virtualization/2.4/html-single/installing_and_using_the_migration_toolkit_for_virtualization/index#selecting-migration-network-for-virt-provider_mtv

 [2] https://docs.openshift.com/container-platform/4.13/networking/multiple_networks/configuring-additional-network.html