Setting Up the RHEV Virtual Infrastructure - Getting Started with Red Hat Enterprise Virtualization - page 53

Logical networks
A logical network is mainly used to isolate network traffic by functionalities. You can run
your virtual workloads on a host with a single Network Interface Controller ( NIC ), but it
is not recommended to run your mission critical workloads for optimal performance. The
following are five different types of network traffic you need to consider during the design
phase of RHEV:
• RHEV-M network : This is the first logical network created by the RHEV hyper-
visor installer and attached to the specific NIC of your hypervisor host. It is
primarily used for manager and hypervisor heartbeat communication, and also for
live migration of virtual machines.
• Virtual machine networking traffic : This type of network traffic is primarily
used by your application and end user to access the application that runs on the
guest.
• Storage network : This network is primarily used in a scenario where network
storage such as NFS or iSCSI is used as data domains to segregate storage traffic.
• Live migration traffic : This type of network traffic allows you to dedicate NIC
and attach to the Logical Network for Live Migration traffic of virtual machines
across hosts.
• Display console : This is used to access the virtual machine console over the net-
work using the spice or VNC protocol for remote administration.
In addition to these networks, other networks can be defined and used to segregate virtual
machine traffic from the management networks, or isolate traffic between groups of virtual
machines in the same cluster as per the requirement.
The use of VLANs on logical networks also allows a single network interface to be associ-
ated with multiple, differently VLAN-tagged logical networks. If VLAN tagging is not
used, then each logical network must be associated with one individual physical NIC or
bonded device of the hosts. You can't create multiple logical networks on the same NIC.