This RFE is opened regarding supportability of multi-NIC  in ROSA.

This feature is a crucial part of virt on ROSA. Without a bridge network, all VMs would need to be treated like Pods to be accessed from outside the cluster, which requires customers to handle these VMs differently from how they manage VMs on VMware.

With self-managed OpenShift, adding additonal NICs to worker nodes is supported.
  
With additional NICs, customers can separete the network into like service network for VMs, Day2 operation network like live migration newtork and  storage. 
This is not only a reference architecture for OCP-V on-premises by Red Hat[1], but also a common and sensible network design for enhancing security and preventing interference between different types of network traffic

[1] https://access.redhat.com/sites/default/files/attachments/openshift_virtualization_reference_implementation_guide_0.pdf

An extra NIC allows customers to bridge the VM IP addresses to the network outside the ROSA cluster, enabling them to continue using VM services hosted on those IP addresses. Without the network bridge feature, customers would need to convert their non-HTTP VM services into HTTP-based services through 'Ingress,' or expose their services using 'NodePort,' which would require changing both the original IP addresses and TCP ports.