Red Hat Enterprise Virtualization uses networking to support almost every aspect of operations. Storage, host management, user connections, and virtual machine connectivity, for example, all rely on a well planned and configured network to deliver optimal performance. Setting up networking is a vital prerequisite for a Red Hat Enterprise Virtualization environment because it is much simpler to plan for your projected networking requirements and implement your network accordingly than it is to discover your networking requirements through use and attempt to alter your network configuration retroactively.

It is however possible to deploy a Red Hat Enterprise Virtualization environment with no consideration given to networking at all. Simply ensuring that each physical machine in the environment has at least one Network Interface Controller (NIC) is enough to begin using Red Hat Enterprise Virtualization. While it is true that this approach to networking will provide a functional environment, it will not provide an optimal environment. As network usage varies by task or action, grouping related tasks or functions into specialized networks can improve performance while simplifying the troubleshooting of network issues.

Red Hat Enterprise Virtualization separates network traffic by defining logical networks. Logical networks define the path that a selected network traffic type must take through the network. They are created to isolate network traffic by functionality or virtualize a physical topology.

The rhevm logical network is created by default and labeled as the Management. The rhevm logical network is intended for management traffic between the Red Hat Enterprise Virtualization Manager and virtualization hosts. You are able to define additional logical networks to segregate:

For optimal performance it is recommended that these traffic types be separated using logical networks. Logical networks may be supported using physical devices such as NICs or logical devices, such as network bonds. It is not necessary to have one device for each logical network as multiple logical networks are able to share a single device. This is accomplished using Virtual LAN (VLAN) tagging to isolate network traffic. To make use of this facility VLAN tagging must also be supported at the switch level.

The limits that apply to the number of logical networks that you may define in a Red Hat Enterprise Virtualization environment are: