A virtual machine (VM) is a software implementation of a computing environment in which an operating system (OS) or program can be installed and run. The VM typically emulates a physical computing environment, but requests for CPU, memory, hard disk, network, and other hardware resources. These are managed by a virtualization layer which translates these requests to the underlying physical hardware.

You can use an Open Virtualization Archive (OVA) file to deploy VM. The OVA file package simplifies the process of deploying a VM by providing a complete definition of the parameters and resource allocation requirements for the new VM.

You can also install Cisco IOS XRv 9000 Router using an .iso file and manually create the VM in the hypervisor.

A hypervisor enables multiple operating systems to share a single hardware host machine. While each operating system appears to have the dedicated use of the host's processor, memory, and other resources, the hypervisor actually controls and allocates only needed resources to each operating system and ensures that the operating systems (VMs) do not disrupt each other.

Installation of Cisco IOS XRv 9000 Router is supported on selected Type 1 (native, bare metal) hypervisors. Installation is not supported on Type 2 (hosted) hypervisors, such as VMware Fusion, VMware Player, or Virtual Box. The following table lists hypervisor versions supported in the latest Cisco IOS XR Software Release.

The features available in a hypervisor may differ depending on their type. Not all hypervisor features in a given version may be supported. The hypervisor versions listed are those officially tested and supported by Cisco IOS XRv 9000 Router. See the following sections for more information.

• VMware ESXi Support Information

The type of NIC and the maximum number of NICs supported by a hypervisor is dependent on the particular Cisco IOS XR release in use. Some Cisco IOS XR software versions and hypervisors also support the ability to add and remove NICs without powering down the VM. This feature is known as NIC Hot Add/Remove.

This table lists the supported NICs for each VM instance.

See the section Installation Requirements for KVM for information on physical NICs supported by the Cisco IOS XRv 9000 Router in KVM environments.

Cisco IOS XRv 9000 Router limitations are:

• Cisco IOS XRv 9000 Router interface bandwidth defaults to 1GB for all virtualized interfaces, irrespective of the hypervisor’s physical NIC bandwidth.

• When a Cisco IOS XRv 9000 Router is using virtualized interfaces or virtual functions (not physical pass-through), and that interface is directly connected to a physical router and the physical router’s connecting interface goes down, the change is not reflected on Cisco IOS XRv 9000 Router. This is because the Cisco IOS XRv 9000 Router is actually connected to the hypervisor’s vSwitch and the vSwitch uplink port is connected to the physical interface of the router. This is expected behavior.

• Cisco IOS XRv 9000 Router provides an MTU range of 64-9216 bytes but, Cisco advises you to use minimum MTU value of 68 bytes. However, VMWare ESXi vSwitches support maximum frame size of 9000 bytes.

Use Cisco Feature Navigator to find information about platform support and software image support. Cisco Feature Navigator enables you to determine which Cisco IOS XR software images support a specific software release, feature set, or platform. An account on Cisco.com is not required to access Cisco Feature Navigator.

To see if a feature is supported by a Cisco IOS XR release, to locate the software document for that feature, or to check the minimum Cisco IOS XR software requirements with your router, Cisco maintains the Software Advisor tool on Cisco.com. You must be a registered user on Cisco.com to access this tool.

Cisco IOS XR software release notes provide the following information:

• Platform support

• Memory recommendations

• New features

• Open and resolved severity 1 and 2 caveats

Release notes are intended to be release-specific for the most current release, and the information provided in these documents may not be cumulative in providing information about features that first appeared in previous releases. See Cisco Feature Navigator for cumulative feature information.

For more information, see the Cisco IOS XRv 9000 Router Release Notes page.

VMware supports various features and operations that allow you to manage your virtual applications and perform operations such as cloning, migration, shutdown and resume.

Some of these operations cause the runtime state of the VM to be saved and then restored upon restarting. If the runtime state includes traffic-related state, then on resumption or replaying the runtime state, additional errors, statistics, or messages maybe displayed on the user console. If the saved state is just configuration driven, you can use these features and operations without a problem.

This table lists not-supported VMware features and Operations: High Availability, in the latest Cisco IOS XR Software Releases.

Table 10. Not-supported VMware Features and Operations: High Availability

Entities	Status	Description
VM-Level High Availability	Not supported	To monitor operating system failures, VM-Level High Availability monitors heartbeat information in the VMware High Availability cluster. Failures are detected when no heartbeat is received from a given virtual machine within a user-specified time interval. VM-Level High Availability is enabled by creating a resource pool of VMs using VMware vCenter Server.
Host-Level High Availability	Not supported	To monitor physical servers, an agent on each server maintains a heartbeat with the other servers in the resource pool such that a loss of heartbeat automatically initiates the restart of all affected virtual machines on other servers in the resource pool. Host-Level High Availability is enabled by creating a resource pool of servers or hosts, and enabling high availability in vSphere.
Fault Tolerance	Not supported	Using high availability, fault tolerance is enabled on the ESXi host. When you enable fault tolerance on the VM running Cisco IOS XRv 9000 Router, a secondary VM on another host in the cluster is created. If the primary host goes down, then the VM on the secondary host will take over as the primary VM for Cisco IOS XRv 9000 Router.

Note	The Cisco IOS XRv 9000 Router does not support Active/Standby control plane redundancy.