Map Network Interfaces to VM Network Interfaces

A network interface is a virtual port on a router that:

  • provides entry and exit points for network traffic,

  • is mapped by virtualization software to physical network hardware, and

  • supports various functions such as WAN, LAN, and management connectivity.

Interface numbering

Network interfaces in Cisco Catalyst 8000V routers are functionally similar to those on hardware-based routers, and are named according to the Gigabit Ethernet (GE) numbering, which varies by version.

  • The interface port numbering begins at 1 and increases according to the number of supported vNICs. See VM Requirements for more details.

  • Gigabit Ethernet interface 0 is not supported.

  • Any interface can be designated as a management interface using Day 0 bootstrapping. For details, see Day 0 Configuration.

This chapter specifies how you can map the logical interface on Cisco Catalyst 8000V with the vNIC and the vNIC MAC address. The sections in this chapter explain how to add and delete network interfaces. They also describe the supported interface speed for Cisco Catalyst 8000V .

Supported network interface speeds

This table specifies all the network interface speeds that are supported for Cisco Catalyst 8000V

Cisco IOS XE release

Interface speed (Mbps)

Cisco IOS XE 17.15.1a and later

Up to 40,000

Cisco IOS XE 17.9.1 to Cisco IOS XE 17.14.x releases

Up to 25,000

Cisco IOS XE 17.4.1 to Cisco IOS XE 17.8.x releases

Up to 10,000

Interface mapping limitations and configurations

See this list to view all the guidelines and limitations for configuring and managing interface mapping in Cisco Catalyst 8000V.

  • Neither hot add nor hot delete operations for interfaces are supported in controller mode. If you wish to change interface mappings in controller mode, use the request platform software sdwan config reset command.

  • Removing a vNIC without updating the Cisco Catalyst 8000V network interface configuration may result in configuration mismatches upon reboot. In this situation, logical vNIC names and MAC addresses can be reassigned. As a result, GigabitEthernet interfaces might map to different physical interfaces on the hypervisor.

  • After adding or deleting network interfaces on the VM, verify the updated vNIC-to-interface mapping before changing network interface configurations.

Network interface mapping options in ESXi

Supported interface mappings in the ESXi hypervisor are:

  • Each Cisco Catalyst 8000V router interface maps to a unique host Ethernet interface.

  • Multiple Cisco Catalyst 8000V interfaces map to a single ESXi host Ethernet interface.

  • Cisco Catalyst 8000V interfaces map directly to a trunk interface on the ESXi vSwitch.

View interface mapping

Perform these steps to view the interface mapping in Cisco Catalyst 8000V.

Cisco Catalyst 8000V maps the GigabitEthernet network interfaces to the logical virtual network interface card (vNIC) name assigned by the VM. The VM in turn maps the logical vNIC name to a physical MAC address.

When you boot a Cisco Catalyst 8000V instance for the first time, the router interfaces are mapped to the logical vNIC interfaces that were added when the VM was created.

Procedure

To view the mapping between the interface on the router with the vNIC and the vNIC MAC address, run the show platform software vnic-if interface-mapping command.

Example:


Router# show platform software vnic-if interface-mapping
--------------------------------------------------------------------------
Interface Name        Short Name     vNIC Name                Mac Addr
--------------------------------------------------------------------------
GigabitEthernet2       Gi2        eth2 (vmxnet3)           0050.5689.0034
GigabitEthernet1       Gi1        eth1 (vmxnet3)           0050.5689.000b
--------------------------------------------------------------------------

The vNIC name shown in the display identifies a logical interface that the Cisco Catalyst 8000V instance uses to associate with the interface on the hypervisor. his logical vNIC name does not always correspond to the NIC name configured during VM installation. For example, 'eth1' in the display might not link to 'NIC1' from the VM setup process.

GigabitEthernet0 interface is no longer supported.

Add network interfaces

This topic provides high-level information about adding network interfaces to a VM. First, add vNICs on the VM to add GigabitEthernet interfaces on Cisco Catalyst 8000V.

To add a vNIC on the VM:

  • Add the vNIC through the virtual machine settings that are supported for the hypervisor. For details on adding vNICs, see the individual hypervisor documentation.

  • Interface hot add is not supported on Cisco Catalyst 8000V in controller mode. Use the request platform software sdwan config reset command to add an interface in this mode.

Remove a network interface

You might need to use a two-step hot remove procedure to remove a vNIC from the VM, depending on the hypervisor. Check if your hypervisor supports a two-step hot remove by looking for hypervisors with vNIC Two-Step Hot Remove Support = Yes.

Before you begin

Power down the VM before you remove an interface.

Procedure

Step 1

Run the clear platform software vnic-if interface GigabitEthernetinterface-number command.

Example:

Router# clear platform software vnic-if interface GigabitEthernet4

Clears the interface on the VM.

Here, the value for interface-number can be any number between 0 and 32.

Note

 

This command might not be supported on all Cisco IOS XE releases.

Step 2

Remove the vNIC from the hypervisor configuration.

his step depends on your hypervisor. Refer to your hypervisor's official documentation for instructions on how to remove a vNIC.

Step 3

Reboot the router.

Configure interface mapping for cloned virtual machines

Perform the steps mentioned in this task on the original VM first before cloning to prevent the interface mapping from becoming mismatched.

When you first install a Cisco Catalyst 8000V instance, a database that maps the vNIC name to the MAC address is created. This database is used to maintain a persistent mapping between the router interfaces and the vNIC-to-MAC address mapping in case you add or delete vNICs. The interfaces are mapped to the stored Universal Unique Identification (UUID) maintained by VMware.

The mapping between router network interfaces and vNICs applies only to the current VM where the router is installed. After cloning the VM, the stored UUID does not match the new UUID, resulting in interface mappings that do not align with the router configuration.

Before you begin

Ensure that the original VM includes the number of configured vNICs required on the cloned VM.

Procedure

Step 1

Enter the clear platform software vnic-if nvtable command on the original VM.

This command clears the persistent interface database on the original VM and updates the interface mapping to the hypervisor.

Step 2

Reboot the Cisco Catalyst 8000V.

Step 3

On the cloned VM, verify the interface mapping using the showplatformsoftwarevnic-ifinterface-mapping command.

Step 4

Configure the router interfaces on the cloned VM accordingly.

The router configuration on the cloned VM should match that of the original VM.